QOS static routing / Dynamic Routing .. - Okay eigrp bgp, vrf, spanning tree, trunking

port sharing VLAN Port Channel --> On going - LACP Port Mapping Port Security VRF Stacking Subnets VLAN Concepts BGP Static routes Eigrp STP STP multipath

1. Cisco switch Stack 3750 stack. 2. Port-channel. 3. Vlan & VTP modes. 4. STP. Routing - Static routes. ,BGP on MPLS.,EIGRP.,MPLS-VRF.,Sub netting.

Firewall- Nat & types of Nat.,Basic idea on ACL.

Port Mirroring Port Mirroring is used on a network switch to send a copy of network packet seen one switch port to a network monitoring connection on another switch port. Generally referred as the SPAN ( Switch port Analyzer) Layer 3 Switch High Performance devices. Layer 3 switch very little differ from routers. A layer 3 switch support the routing protocols Both inspect the incoming & outgoing packet and dest Layer 2 switch, frames are based on the MAC address information, Layer 3 switch frames are based on the network-layer information. Layer 2 switching does not look inside a packet for network-layer information. Layer 2 switching is performed by looking at destination MAC address within a frame. Layer 2 switch maintain the MAC address table. Layer 2 switch broadcast the frames and received the information. Layer 3 switching operates at the network layer. It examines packet information and forward packets based on their network- layer destination address. VRF : 1. Virtual Routing and forwarding is used on the MPLS network. 2. VRF is maintain the multiple routing table on the single router. 3. Virtual routing and forwarding is a technology included in IP ( Internet Protocol) network routers that allow multiple instances of the routing table to exist in a router and work simultaneously. 4. Increases functionally by allowing network paths to be segmented without using multiple devices. 5. VRF acts like a Logical router , but while a logical router may include many routing tables. 6. Virtual routing and forwarding is a technology implemented in the IP network routers that allow multiple instances of a routing table to exist on the same router in the same time 7. Multi protocol Label Switching ( MPLS) VPN technology. 8. Virtual Network enable administrator to split a physical link into multiple virtual link completely isolated one from the others. Virtual Link will be dedicated to traffic from a specific application or customer. MPLS functionally based on P ( Provider) router, PE ( Provider Edge) router and CE ( Customer edge) router. One PE router can hold and manage multiple virtual routing. If you are running in a private environment , you can use MPLS VPN to separate services.

The Route distinguisher (RD ) is a number which help identify a VPN in a provider network and allow for overlapping IP space. The Route target (RT) indicates the VPN membership of a route and allow VPN routes to be imported or exported into or out of your VRF Spanning Tree 1. STP is the link layer network protocols that ensure a loop free topology. 2. Basic functionally of the STP is prevent bridge loop and ensuring broadcast radiation. a. Select Root Bridge We need to select the root bridge with the smallest bridge ID, Each bridge has a unique identifier and configure the selected ID . Based on the priority value the bridge b. Determine the least cost paths to the root bridgec. Bridge Protocol Data Unit ( BPDU ) BPDU frame using the Bridge ID and MAC address of the port itself and Source and Destination address. i. BPDU exchange regularly and enable switch keep track of network changes and start and stop forwarding at ports as required. ii. BPDU are exchanged regularly ( every 2 sec) 3, Blocking ,Listening Switch process BPDU and awaiting new possible information., Learning ,Forwarding ,Disabled Spanning tree protocol is a link management protocol that provide path redundancy while prevening undesirable loops in the network. Multiple active paths between stations cause loops in the network. If the loop exists in the network topology, the potential exists for duplication of message. Election of the Root Switch 1. The election of a unique root switch for the table 2. The election of a designated switch for every switched LAN segment. 3. The removal of loops in the switched network BPDU 1. The Unique switch identifier ( MAC address) associated with each switch. 2. The path cost to the root 3. The port identifier with each switch.

BPDU One switch is elected as the root switch. The shortest destination to the root switch calculated for each switch. Blocking, Listening, Learning, Forwarding, Disabled. VTP VTP ( VLAN Trunking Protocol) Cisco proprietary Layer 2 messaging protocol that manage the addition, deletion and renaming of VLAN on a network wide basis. VTP reduce the administration in a switch network. VLAN information distributed to all switches by VTP domain. VTP Operation on three mode 1. Server In the VTP mode , create, modify the VLANS 2. Client VTP client is works like Server, but not able to create , delete 3. Transparent The switch does not participate in VTP, A VTP transparent switch will not advertise its VLAN configuration and does not synchronize. VTP sends message between trunked switches to maintain VLAN on these switch Port Security 1. Port security can do based on the MAC address 1. MAC blocking 2. MAC learning Stacking The term Stack refers to the group of switch that have been set up in the way. 1. Stackable switch is always single management interface 2. Switch stack has up to nine stack members connected through their stackwise port. A switch stack always has one stack master. 3. The stack member number (1 to 9 ) identifies each member in the switch stack. 4. Collectively use the Cisco switches. A switch stack is a set of up to nine Catalyst 3750 switches connected through their StackWise ports. One of the switches controls the operation of the stack and is called the stack master. The stack master and the other switches in the stack are stack members.

A switch member are eligible stack masters. If the stack master becomes unavailable, the remaining stack members participate in electing a new stack master from among themselves. The switch with the high priority value become the stack master. Switch running the cryptographic version of the SMI or EMI (Standard multiplayer image) or EMI software. Manage the switch stack through a single IP address. Port Channel Port channel support 2 , max 8 interfaces. The best way to use 2, 4 or 8. The load balancing is based on layer 2/3 or 4. Port channelling is make a communication between router & Switch. Etherchannel EtherCannel is a port trunking technology used primarily on cisco switches. It allow grouping several physical Ethernet link to create one logical Ethernet link for the fault-tolerance and high-speed link between switchs, router and servers. A limitation of Etherchannel is that all the physical ports in the aggregation group must reside on the same switch. Firewall A firewall is a program or hardware device that filters the inbound and outbound traffic. Three method of controlling the traffic. 1. Packet Filtering - Packets are analyszed against a set of filters. Packets that make it through the filters are sent to the requesting systems and all others are discarded. 2. Proxy Service Information from the internet is retrieved by the firewall and then sent to the requesting system and vice versa. 3. State full Inspection It does not examine the content of each packet but instead compares certain key parts of the packet to a database of trusted information. Inbound and outbound are monitored for specific characteristic, then incoming information is compared to these characteristic. If the comparison yeald the reasonable match, the traffic allowed thought, otherwise its discarded Security Level. PIX have very simple mechanisms to control traffic between interface. The ASA allow traffic pass from trusted to untrusted , but not the reverse. The traffic can pass from interface with high security levels to interfaces with lower security levels. ASA block the lower level to high level.

Security level 100The highest possible level, it is used by the inside interface by default.

Using the trusted-untrusted terminology, this level is considered the most trusted.

Security level 0The lowest possible level, it's used by the outside interface by default,

making it the most untrusted interface. Traffic can pass from this interface to other interfaces only if manually configured to do so.

Security levels 199 Can be assigned to any other interface on the PIX. On a three-

pronged PIX firewall, the inside is typically 100, the outside is 0, and the third interface could be 50. Traffic from interfaces between 1 and 99 can pass through to the outside (0), but it is prevented from passing to the inside (100). This is because the interface has a lower security level setting than the inside. Cisco 6500 Super Wiser Engineer 32 Static Routing Vs Dynamic Routing. Static routing is not really a protocol, simply the process of manually entering routes into the routing table via a configuration file that is loaded when the routing devices starts up. Static route is a route that is created manually by the network adminstrator. Dynamic route are created by routing protocol. http://www.trainsignaltraining.com/free-video-training/free-ccna-training-videos-static-routing-andrip/ Static routing administrative distance is one. IGRP default administrative distance is 100 Static routing is manually entering the route based on the best path consideration. Dynamic routing is Dynamic routing protocols are software application that dynamically discover network. A router will learn routes to all directly connected network. It will learn routes from other routers that run the same routing protocols. The router will then sort through its list of routes and select the best path. EIGRP ( Enhanced Interior Gateway Routing Protocol) 1. It is link state routing protocol. 2. Cisco Preparatory routing protocol & Distance vector routing protocol. 3. Routing optimisation is based on the Diffusing update algaritham (DUAL)

4. Distance Vector Routing Protocol Bellman Ford algorithm to find shortest paths. The exchange a vector of distance to all destination. No future topology information exchange. 5. Link state routing protocols Based on the algorithm find the shortest path. They work by exchanging a description of each node and its exact connections to its neighbours. 6. EIGRP allows for equal cost load balancing, incremental routing updates and formal neighbour relationship 7. EIGRP reduces bandwidth usage. Its updates only when topology changes occur. 8. Support of Variable Length subnet Masks (VLSM) 9. Using Hello messages, EIGRP sessions establish and maintain neighbor relationships with neighboring routers. 10.EIGRP format packet ( hello / ACk, Updates, Queries, Replies, Request ) 11.EIGRP administrative distance is 120 12.EIGRP only send the updated information if any network changes. 13.EIGRP Default hop count is 224 14.IGRP default hop count s 111 15.EIGRP use reduce the bandwidth 16.EIGRP will learn the successor and feasible successor. 17.EIGRP maintain three database Neigbor DB, toptoplogy DB, IP routing table 18.EIGRP default hold time is three times of Hello packets. 19.RTP ( Reliable Transport Protocol) is responsible for guarabteed 20.Default hello interval is 5 second. 21.Update, query & replay packet , replay Acknowledgement oriented. 22.Hello, ACK are NON Acknowledgment oriented. 23.EIGRP DUAL a. Tracks all routs advertised by neighbour. b. Select the loop free successor and select the feasible successor. c. If successor is fails , select the feasible successor. 24.DUEL is used to select the best path OSPF

1. Its is link state routing protocol. Generate routing update when any network changes. 1. Response quickly as the network changes. 2. Send triggered update when network changes occurs 3. Send periodic update, link-state refresh, and such every 30 min 2. Neighbour Table, Topology table, Routing table Link state data structure. 3. Digistra algoritham calculate the all possible routes. 4. OSPF Area - Characteristics 2. Minimizes routing table entry. 3. Localization impact of any topology changes. 4. Details LSA flooding stop at the area boundry. 5. Require hierarchical network design. 6. Area border router (ABR) 7. OSPF select the DR ( Designated Router) and BDR ( Backup Designated router) 8. OSPF protocol that builds three tables : Neigbour table, LS topology table and routing table. 9. OSPF protocol have five type of packet, hello, database description, Link state Request( LSR), Link State Update (LSU) and ACK. 1. Hello Builds adjucent between neighbours. 2. Database Description ( DBD) check for database syncronization between router. 1.

IGRP.. It is distance vector routing protocol. Its use metric as a bandwith

Cisco switch Stack 3750 stack. Catayst 3750 switch that run cisco IOS software relase 12.2 Ling Aggregation Control Protocol ( LACP ) and Port Aggregation Protocol ( PAgP) is a Cisco proprietary protocols that run on Cisco Switch. PAGP cannot be enabled on cross-Stack ether channels.

LACP is supported on cross stack etherchannels from Cisco IOS. LACP packets only with partnet interfaces with the active or passive mode configuration. We can configure up to 16 ports form a channel. Eight of the port are in active mode and other eight are in standby mode. New method for collectively utilizing the capabilities of a stack of switch. Switch intelligently join to create a single switch unit with a 32 gbic Switch can be added to and deleted from a working stack without affecting performance. Switch are united into a single logical units using special stack interconnected cables that create bidirectinoal closed loop path. Layer 2 and Layer 3 forwarding layer 2 forwarding is done with a distribution layer. Layer 3 is done in a centralized manner. Cisco Catalyst 3750 series switch has a single IP address and is managed as a single object. The single IP management applies to active fault detection, VLAN creation , Modification and deletion , Security and QoS controls. Cisco stackwise technology units up to nine individual cisco 3750 switch into a single logical units. This single stack will allow share the same network topology, MAC address and routing information. Bi-directional flow To efficiently load balanced the traffic. On line stack adds and remove. Physical sequential linkages A break of the any one cable will result in the stack bandwidth being reduced to half of its full capability. Subsecond Failover within microsecond of a brakage of one part of the path Single Management IP address Master Switch Election 1. User Priority network manager can select the which switch as a master. 2. H/w and S/W priority 3. Default configuration. 4. Uptime 5. MAC address Shared network Topology information - The master switch is responsible for collecting and maintaiing correct routing information. It send periodic update to all subordinate switchs. The master switch is responsible for routing control and processing.

Subordinate switch activity Switching Mode Fast forwards Fast forwards offers the lowest level of latency by immediately forwarding a packet after receiving the destination address. In Fastforward mode, latency is measured first bit received to first bit transmitted (FIFO) Fragment Free Fregment free switching filters out collision fragments, the majority of packet errors before forwarding begins. Store and Forward. - Complete packet are stored and checked for error prior to transmission. In Sore and forward mode, Latency is measured last bit received to first bit tranmitted or LIFO ( Last in Fast out) What is administrative distance ? Adminsitrative distance is the feature that routers use in order to select the best path when there are two or more different routes to the same distinaiton from two different routing protocol. AD define the reliability of a routing protocol. AD distance is the first criterion that a router used to determine which routing protocol to use if two protocols provide route information for the same destination. The smallest administrative distance value is more reliable protocol. Administrative distance is used to select the best path when there are two or more different routes to the same distance from two different routing protocols.

Route Source Connected interface Static route Enhanced Interior Gateway Routing Protocol (EIGRP) summary route External Border Gateway Protocol (BGP) Internal EIGRP IGRP OSPF Intermediate System-to-Intermediate System (IS-IS) Routing Information Protocol (RIP)

Default Distance Values 0 1 5 20 90 100 110 115 120

Exterior Gateway Protocol (EGP) On Demand Routing (ODR) External EIGRP Internal BGP Unknown*

140 160 170 200 255

Clock rate The clock rate interface command has been enhanced for the synchronous serial port Subnet A subnet is a identifiable separate part of a organization network. Class Address Class A addresses begin with 0xxx, or 1 to 126 decimal. Class B addresses begin with 10xx, or 128 to 191 decimal. Class C addresses begin with 110x, or 192 to 223 decimal. Class D addresses begin with 1110, or 224 to 239 decimal. Class E addresses begin with 1111, or 240 to 254 decimal. MPLS Multiprotocol Label Switching is a mechanisam is high performance telecommunication network which directs and carries data from one network node to the next. MPLS is a highly scalable, Protocol agnostic, MPLS is an efficient encapsulation mechanisam. MPLS was originally presented as a way of improving the forwarding speed of routers but is now emerging as a crucial standard technology that offers new capabilities for large scale IP network. MPLS terminology, the packet handled nodes or router are called Label switched router (LSR) Is the telecommunication network. MPLS is the standard technology for speeding up network traffic flow and make it easy to manage MPLS VRF ( Virtual Routing and forwarding ) is a technology that allow multiple instances of a routing table VRF is the key element in the Cisco MPLS VPN technology.

ACL

Empty ACL permit all traffic Standard IP 1?99 ,1300 ?1999 Extended IP 100?199, 2000 ?2699 access-list acl_collector permit icmp any any access-list acl_collector permit ip any any Router( config) # access-list ACL# permit | deny conditions Standard Access Control list (ACL) are Cisco IOS based commands used to filter packets on cisco router based on the source IP address of the packet. Extended access control list have the ability to filter packet based on source and destination IP address. Numbers between 1 and 99, or any number between 1300 and 1999 can be used in a Standard ACL.

CISCO PIX Firewall BASIC PIX Device Manager ( PDM ) PIX firewall provide wide range of security NAT , Content Filtering, URL filtering, IPSec VPN, DHCP Server / Client, Static NAT NAT NAT is a way to map a range of global address to an inside or peimeter (DMZ) address. 1. Static NAT One to one basis 2. Dynamci NAT Nap a unregistered IP address to a pool of registered IP 3. Overloading is the form of dynamic NAT but maps multiple unregistered IP address to one single registered IP address. This is know as PAT or single address NAT. NAT Terms.. Inside Local Address An IP address assigned to a host inside a network. Inside Global Address A legitimate IP address assigned by the NIC or service provider that represents one or more inside local IP address to the outside world. Outside Local Address

Outside Global Address - x

ARP and RARP Address Translation ARP maps IP address into MAC address. And ARP maps MAC address into IP address BGP. BGP is a protocol for exchanging routing information between gateway hosts in a network of autonomous systems. The routing table contains a list of known routers, the address they can reach and a cost metric associated with the path to each router. Learns multiple paths via internal and external BGP speakers. Picks the best path and installs in the forwarding table. Best path is sent to external BGP neighbour. Classless Inter Domain routing ( CIDR) BGP Introduction Used for carrying routing informaton between AS's path vector Protocol Incremental Runs over TCP - 179 Conveys Informatoin about AS BGP- General Operation Learns multiple paths via internal and external BGP speakers Picks the best path and installs in the IP forwarding table. Policy applied by influencing the best path selection. Load balancing - BGP does NOT load balancing traffic; it choose & installs a "Best " route BGP Relationship with IGP - BGP carries full internet routing table - IGP are used to carry next hop and interior network information. Autonomous System (AS) - Collection of network with same routing policy. - Single routing protocol BGP Path Selection Algoritham - Do not consider path if not route to next hop. - Sortest algoritham path VLAN Creation To define a VLAN on the cisco device, we need a VLAN ID, a VLAN name, Ports Step 1 Get the current configuration Step 2 - Create a vlan using VLAN X , where X is the ID Step 3 Name the VLAN < VLAN Name> Step 4 Create the VLAN with the network range Step 5 End configuration mode by END Step 5 : save conf by wr mem

1. VLANs are broadcast domains defined within switches to allow control of broadcast, multicast, unicast and 2. VLAN are defined on the switch in an internal database know as the VTP database. After vlan has been created, port are assigned to the VLAN Router Configuration Tutorial 1. User EXEC 2. Privileged EXEC 3. Global Config. 4. Interface Config. 5. Set up RIP.. RIP default behavior is send to ver 1 updateds, but to acceptable from ver 1 and 2. Sending update every 30 seconds Invalid after 180 Sec, Hold down 180 , flushed after 240. Difference between RIP V1 & V2 ? RIP V1 Classful routing protocol RIP V2 Classless routing protocol RIP V1 Subnet mask are NOT included in the routing update. RIP V2 Subnet mask are included in the routing update. Cisco 6509 Switch Details. Supports all Catalyst 6500 modules, including all:

Supervisor engines Switch fabric modules Fast Ethernet modules Gigabit Ethernet modules 10 Gigabit Ethernet modules Voice modules Flex Wan Modules ATM modules Multi Gigabit services modules (content services ,firewall, intrusion detection, IPSec/VPN, network analysis, and SSL acceleration) The Cisco Supervisor engine 720 offer a strong set of security features. The supervisor engine 720 builds on the proven Cisco Express forwarding ( CEF) architecture, by supporting centralized forwarding ( CEF) and distributed forwarding ( dCEF) There are three flavore, PFC3A, PFC3B, PFC3BXL MSFC3 The MSFC3 is an integral part of the supervisor engine 720, providing high performance multiplayer switching and routing intelligence.

What is the difference between gateway and firewall? A network gateway joins two network together through a combination of hardware and software. A network firewall guards a computer network against unauthorized incoming or outgoing access. Network firewall may be hardware devices or software programs. What is the difference between router ACLs and Firewall ACLs? Router are designed to route traffic, not stop Firewall are designed to examine and accept / reject traffic. Both ACL are do the same job. Depending upon our requirement we do our ACL configuration. Can traceout command work across the firewall? If No then why? If Yes then why? Firewall A firewall filters both inbound and outbound traffic. What different types of firewall are there ? 1. 2. 3. 4. Packet filters Circuit level gateways Application level gateways Stateful multiplayer inspection firewalls

Packet filtering firewalls work at the network level of the OSI model, or the IP layer of TCP/IP. A router is a device that receives packets from one network and forwards them to another network. In a packet filtering firewall each packet is compared to a set of criteria before it is forwarded. Most routers support packet filtering. http://www.vicomsoft.com/knowledge/reference/firewalls1.html#1 circuit level gateways work at the session layer of the OSI model, or the TCP layer of TCP / IP. This is useful for hiding information about protecting networks. Circuit level gateway are relatively inexpensive and have advantage of hiding information. Application level gateway also called proxies are similar to circuit level gateway expect that they are application specific. The can filter packet at the application layer of the OSI model. Stateful multiplayer inspection firewall. They filter packets at the network layer.

What is IP Spoofing? Many firewall examine the source IP address of packet to dertmine if they are legitimate.

IP spoofing This is useful technique , since many system define which packet may and which packets may not pass based on the sender IP address. Routing Funcion The routing function is responsible for learning the logical topology of the network and then make decision based on the knowledge Switching Function It is concerned with moving data across the router. It is responsible for forwarding the datagram. Protocol Update Timer Technology RIPv1 Every 30 seconds for entire routing table. Distance vector. RIPv2 Every 30 seconds for entire routing table. Distance vector. OSPF Incremental with only the network change. However, 30 minutes after the last update was received, a compressed version of the table is propagated. Link state. EIGRP Incremental updates with network change only. Advanced distance vector, sometimes called enhanced distance vector or a hybrid routing protocol. IGRP Updates every 90 seconds with incremental updates as needed. Distance vector. BGP-4 Incremental with only the network change. Path vector, sometimes referred to as a type of distance vector routing protocol. IS-IS Incremental with only the network change. However, the router that originated the LSPmust periodically refresh its LSPs to prevent the remaining lifetime on the receiving routerfrom reaching 0. The refresh interval is 15 minutes. This means that approximately 15 minutes after the last update was received, a compressed list of all the links the router has knowledge of is sent to all routers. Link state.

Distance Vector Routing Protocols Versus Link-State Routing Protocols Distance Vector Link-State Sends its entire routing table at periodic intervals out of all interfaces (typically, this is based in seconds). Sends triggered updates to reflect changes in the network. Typically involves updates sent using a broadcast address to everyone on the link. Uses a metric based on how distant the remote network is to the router. (IGRP does not conform to this as a proprietary solution.) Has knowledge of the network based on information learned from its neighbors. Includes a routing table that is a database viewed from the perspective of each router. Uses the Bellman Ford algorithm for calculating the best path. Does not consume many router resources, but is heavy in the use of network resources. Maintains one domain in which all the routes are known. Has a hierarchical design of areas that allow for summarization and growth. For effective use, the addressing scheme should reflect the hierarchical design of the network.

Link State Routing Protocols Sends incremental updates when a change is detected. OSPF will send summary information every 30 minutes, regardless of whether incremental updates have been sent in that time. Typically involves updates sent to those routers participating in the routing protocol domain, via a multicast address. Is capable of using a complex metric, referred to by OSPF and IS-IS as cost. Has knowledge of the network based on information learned from every router in the area.

Has a topological database that is the same forevery router in the area. The routing table that is built from this database is unique to each router. Uses the Dijkstra algorithm. Uses many router resources, but is relatively low in its demand for network resources. Is not restricted by addressing scheme.

Involves slower convergence because information of changes must come from the entire network (but indirectly). Each routing table on every intervening router must be updated before the changes reach the remote end of the network.

RIP V1

OSPF

Is a simple protocol to design, configure, and maintain. Does not require a hierarchical addressing scheme. Does not pass the subnet mask in the routing update and therefore is not capable of classless routing or VLSM. Is limited to a 15-hop diameter network. Does not acknowledge routing updates; just repeats them periodically (every 30 seconds). Has a routing table that is sent out of every interface every 30 seconds (by default). Can transmit information about the network in two messages: the routing update and the triggered update. Uses hop count as a metric, the number of routers to process the data.

Is a complex protocol to design and, in some instances, to configure and maintain. If full benefits of the protocol are to be harnessed, should use a hierarchical IP addressing scheme. Carries the mask in the update and therefore can implement VLSM, summarization, and classless routing. Is unlimited in the diameter of the network, although it is suggested that an area not exceed more than 50 networks. Acknowledges updates. Involves updates sent as required (when changes are seen) and every 30 minutes after no change has been seen. Has protocols for discovering neighbors and forming adjacencies, in addition to protocols for sending updates through the network. These protocols alone add up to nine message types. Uses cost as a metric. Cost is not stated in the RFCs, but it has the capacity to be a complex calculation, as seen in Ciscos implementation.

Layer 3 Routing Versus Layer 3 Switching

It is important to understand the difference between Layer 3 routing and Layer 3 switching. Both terms are open to some interpretation; however, the distinction between both can perhaps be best explained by examining how an IP packet is routed. The process of routing an IP packet can be divided into two distinct processes:

Control planeThe control plane process is responsible for building and maintaining the IP routing table, which defines where an IP packet should be routed to based upon the destination address of the packet, which is defined in terms of a next hop IP address and the egress interface that the next hop is reachable from. Layer 3 routing generally refers to control plane operations. Data planeThe data plane process is responsible for actually routing an IP packet, based upon information learned by the control plane. Whereas the control plane defines where an IP packet should be routed to, the data plane defines exactly how an IP packet should be routed. This information includes the underlying Layer 2 addressing required for the IP packet so that it reaches the next hop destination, as well as other operations required on for IP routing, such as decrementing the time-to-live (TTL) field and recomputing the IP header checksum. Layer 3 switching generally refers to data plane operations.

7200 Router

7200 enable an integrated solution for routing and security including Qos , multicast and miltiprotcol traffic across the vpn. Utilizing the VPN acceleration module (VAM2) , the cisco 7301 and cisco 7200 series VPN routers deliver IPsec encryption scalability to 145 MBps for the most demanding head end , site- to site VPN. Security feature on 7200 Router Control Plane Policing (CPP), Committed Access Rate (CAR) ,Voice & Video Enabled IPSEC (V2PN) , Connected Engine Network module (NM CE) What is ICMP ? ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP. It used the echo test / replay to test whether a destination is reached and responding. It also handles both control and error messages. What is a bandwidth? Every line has a upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth. What is the Frame Relay? Frame Relay is a packet switching technology. It will operate in the data link layer. What are the 3 most common LAN architectures? The 3 most common types of LAN architectures* are:

Ethernet Token Ring ArcNet

How does the nomenclature "10base2" describe Ethernet cable? An Ethernet LAN is often described in terms of three parameters: transmission rate, transmission type, and segment distance. "10base2" means:

10 - transmission rate or through put of 10Mbps

base - transmission type is baseband rather than broadband network (i.e., the signal is placed directly on the cable, one signal at a time) 2 - the maximum segment distance in meters times 100; in this case 200 meters (actually only 185 meters)

What are the key characteristics of 10Base2 Ethernet. A 10Base2 Ethernet LAN conforms generally to the IEEE 802.3 standard. Also known as Thinnet Ethernet, it has the following key characteristics:

Transmits at 10 Mbps Uses Thinnet coaxial cable Supports a maximum of 30 nodes per segment Uses local bus topology Minimum distance between computers is 0.5m (not including drop cables) Maximum length of segment is 185m Up to 5 segments can be connected (but only 3 can accommodate nodes) Connected with BNC connectors (T-connectors) Used primarily for smaller workgroups or departments

What is Token Ring? What IEEE standard does it conform to? Token ring is a relatively expensive LAN architecture that is strongly influenced by IBM. It is very stable and can be expanded without a significant degradation in network performance. Token ring uses the token passing media access control. Data transmission normally occurs at 4 or 16 Mbps depending on the cable. Token ring is normally implemented in a logical ring/physical star topology with a MAU (Multistation Access Unit) as the hub. The maximum number of stations on one ring is 260 for shielded twisted pair and 72 for unshielded twisted pair (UTP). There can be up to 33 MAUs per ring. Token Ring LANs normally use shielded twisted pair (STP) but may also use unshielded twisted pair (UTP) or fiber-optic cable. The maximum distance to the MAU from the workstation depends on the cable and varies from 45 meters for UTP to 100 meters for STP. What is a topology? A topology refers to the manner in which the cable is run to individual workstations on the network. The dictionary defines topology as: the configurations formed by the connections between devices on a local area network (LAN) or between two or more LANs What is a HELLOW protocol used for? The HELLO protocol used time instead of distance to determine optimal routing. It is an alternative to the routing information protocol. What is difference between ARP and RARP ?

The ARP is used to associated the 32 bit ip addrss with the 48 bit physical address, used by a host or a router to find the physical address, used by a host or a router to find the physical addrss of another host on its network by sendigna ARP query packet. THE RARP allows a host to discover its internet address when it knows only its physical address. What is Multicast routing ? Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing. What is IGP( Interior Gateway Protocl)? It is any routing protocol used within an autonomous system What is OSPF ? It in an internet routing protocol that scales well,can route traffic along multiple paths, and uses k What is Load balancing? If the number of incoming clients requests exceeds the number of processes in a server class, the TP Monitor may dynamically start new ones and this is called Load balancing. What is the difference between TFTP and FTP application layer protocols? The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP. The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information. What are the advantages and disadvantages of the three types of routing tables? The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every time there is a change. A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance. A fixed central table lets a manager modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine's table, as with the fixed table. Usually a dynamic table causes the fewest problems for a network administrator, although the table's contents can change without the administrator being aware of the change. What does the Mount protocol do ? The Mount protocol returns a file handle and the name of the file system in which a requested file resides. The message is sent to the client from the server after reception of a client's request.

What is the HELLO protocol used for? The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol. What is the minimum and maximum length of the header in the TCP segment and IP datagram? The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes. What is Protocol Data Unit? The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I - frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame). What are the data units at different layers of the TCP / IP protocol suite? The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media. What is difference between ARP and RARP? The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver. The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address. What is MAC address? The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique. What is terminal emulation, in which layer it comes? Telnet is also called as terminal emulation. It belongs to application layer. What are the types of Transmission media? Signals are usually transmitted over some transmission media that are broadly classified in to two categories:Guided Media:

These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light. Unguided Media: This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony. What are major types of networks and explain? Server-based network. Peer-to-peer network. Peer-to-peer network, computers can act as both servers sharing resources and as clients using the resources. Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration. What is multicast routing? Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing. What is the difference between routable and non- routable protocols? Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router. What are the different type of networking / internetworking devices? Repeater: Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link. Bridges: These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion. Routers: They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission. Gateways: They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They

accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model. What is redirector? Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer. What is packet filter? Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped. What is logical link control? One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection. What is traffic shaping? One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate, congestion would be less common. Another open loop method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping. What is NETBIOS and NETBEUI? NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications. NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets. Why should you care about the OSI Reference Model? It provides a framework for discussing network operations and design. What is Proxy ARP? is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router. What is EGP (Exterior Gateway Protocol)? It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.

What is IGP (Interior Gateway Protocol)? It is any routing protocol used within an autonomous system. What is OSPF? It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet's topology to make accurate routing decisions. What Is Dynamic DNS? A new feature is Dynamic DNS (DDNS) and as you begin to find out more about how name resolution and service location works, it's a feature you'll be quite thankful for. The basic premise behind DNS is that when a client starts it will register its name-to-IP address mapping with the DNS server that it's configured with. This is a giant change from NT 4.0 when administrators had to enter in all DNS records manually. DDNS works similarly to how WINS worked in NT 4.0 where most, if not all, clients were registered dynamically.

What Is Switch?

Today, network designers are moving away from using bridges and hubs and are primarily using switches and routers to build networks. Technology advances are producing faster and more intelligent desktop computers and workstations. The combination of more powerful computers/workstations and network-intensive applications has created a need for network capacity, or bandwidth, that is much greater than the 10 Mbps that is available on shared Ethernet/802.3 LANS. Today's networks are experiencing an increase in the transmission of large graphics files, images, full-motion video, and multimedia applications, as well as an increase in the number of users on a network.

NO. NAME 7 6 5 4 Application Presentation Session Transport

ENCAPS DEVICES / PDU Raw Data

Segments

3 2 1

Network Data Link Physical

Packets Frame Bits

Router Bridges, Switchs HUB,Repeaters

What Is Virtual Private Network?

VPN connections are similar to dial-up connections in that they give remote users access to your network. But unlike dial-up connections, VPNs let you use an existing networkthe Internet, for exampleas the connection medium. VPNs wrap the Point-to-Point Protocol (PPP) packets used in dial-up connections with additional tunneling protocol headers that let the VPN packets travel securely over a shared network. VPN is especially beneficial in situations where users would otherwise incur long-distance charges when dialing in to your network. To use VPN, all you need at the client is a connection to the Internet (and with the proliferation of broadband Internet connections, VPN users can realize significantly greater connection speeds than dial-up users). Of course, because you're communicating over a public network, it's important that you adequately secure data communications. How you secure data communications depends on the tunneling protocol you use.

Port Details

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Shard Folder 445 Terminal Server Access (RDP ) 3389 Citrix TCP 1494 Dyn >- 1023 and UDP 1604 and Dyn >- 1023 Yahoo Messanger TCP 5100 Printer Service port TCP 9100 , 515,631 Mail TCP 25 SMTP SQL TCP -1433 DBS 53 TACACS 49 sftp TCP 115 NTP 123 NNTP - 119 imap 143 Lotus Notes - 1352 tcp

Multicast addresses are in the range 224.0.0.0 to 239.255.255.255.

224.0.0.0 NO body 224.0.0.1 EveryBody 224.0.0.0.9 RIP router

Bridges

Switch

Software-based L2 Device Learn MAC addresses Segment LANs Floods broadcasts Filters Frames Usually less than 16 ports

Hardware-based L2 device Learns MAC addresses Builds a CAM Table Single station or LAN segment on Floods broadcasts Can have 100 or more ports

each port

FCS ( Frame Check Sequence) Uses the standard 16-bit cyclic redundancy check (CRC) for checking frames. The FCS is the number arrived at after running the CRC and this number is placed into the field on the end of the frame. CRC - A mathematical computation to ensure the accuracy of frames transmitted between devices.

An L2 Frame

Layer 2 Ethernet Frame8 6 D MAC 6 S MAC 2 4 D IP 4 TCP S IP Wi nd D Po rt S Po L7 rt Hdr 46 1500

Data Segment

4 F C S

L3 Info L2 Info L4 Info

L7 Info

L2 Info

Address Learning Bridges and Switches place the source MAC address of every frame received into a MAC address table in the switchs memory Frame Forwarding/Filtering The destination MAC address is looked up in the table and an exit port is located Loop Avoidance When multiple connections between switches are created for redundancy, network loops can occur. Spanning-Tree Protocol is used to stop loops while allowing redundancy Layer 2 Switching Logic A frame is received: Cut-through: Copies only the destination address into its buffers Fast switching, but will pass corrupted frames Destination Multicast or Broadcast Destination Unknown Unicast Destination Unicast in MAC Table Destination Unicast Same Port Flood Flood Forward Filter

Low latency because it begins to forward the frame as soon as it reads destination address

the

Store-and-Forward: Copies the entire frame into its onboard buffers and computes the redundancy check (CRC) Latency varies depending on the frame length. cyclic

Fragment Free (Modified): Waits for the collision window (first 64 bytes) to pass before Forwarding Combines error checking with low latency

Address Learning: Building the CAM Table CAM Table is empty at power-on. Switch learns MAC address from Source Address field in Header. Source Address is placed in CAM Table, associated with its port. Can more than one MAC can be associated with a single port? Subsequent frames with Destination Address found in CAM Table are directed to the proper port. Later frames with DA not found in CAM Table are flooded to all ports. CAM entries do age out after a period of inactivity 300 seconds (5 minutes).

CAM Table Address Types Dynamic Learned by looking at the SA (source address) of every incoming frame. Aged out periodically Default is 300 seconds

Permanent/Static Manually configured. Never aged out of CAM table until an administrator makes a change. L2 Address/Port Switches operate primarily at L2 of the OSI Model.

Summary Switches move frames throughout our networks by checking the DMAC address from the CAM Table and forwarding (or filtering if necessary) to the destination. The switchs CAM Table is built by looking at the Source MAC address of every frame that enters the switch. CAM Table entries are removed after 5 minutes of inactivity (by default).

Firewall What is stateful inspection firewall Stateful inspection technology (a.k.a. dynamic packet filtering) in firewalls refers to the ability to track connection "state information" in addition to simple packet filtering for a more robust security. What that means is, the firewall has the ability to base control decisions (e.g. whether to accept/reject/authenticate/encrypt/log attempts) based on previous communication with the external host, as well as other applications connected to it. In other words, stateful inspection allows for a more intelligent decision-making than simple port/packet-based access blocking. A stateful inspection firewall has the ability to retrieve and manipulate information derived from all communication layers and from other applications. Stateful inspection is a firewall architecture that works at the network layer. Unlike static packet filtering, which examines a packet based on the information in its header, stateful inspection examines not just the header information but also the contents of the packet up through the application layer in order to determine more about the packet than just information about its source and destination. Firewall Technologies 1. 2. 3. 4. Packet Filtering Application Layer Gateways Stateful Inspection Content filtering

Packet Filtering The action a device takes to selectively control the flow of data to and from a network. Packet filters allow or block packets, usually while routing them from one network to another (most often from the Internet to an internal network, and vice versa ). To accomplish packet filtering, you set up a set of rules that specify what types of packets (e.g., those to or from a particular IP address or port) are to be allowed and what types are to be blocked. Packet filtering may occur in a router, in a bridge, or on an individual host

A packet filtering router should be able to filter IP packets based on the following foure fields 1. Source IP address 2. Destination IP address 3. TCP / UDP source and Destinition ports Application Level Security Content Filtering The Application data is handed over to a content filtering server that unpacks the dat to see what is inside, and harmful content is then disposed of.. For Example zipped files are unzipped first to see what is inside them, If the content contains a virus it will be discarded or disinfected. File types are identified and undesirable types. E.g executables can be removed, according to the security policy. DHCP Dynamic Host Configuration Protocol. Provides a mechanism for allocating IP addresses dynamically so that addresses can be reused when hosts no longer need them.

Different between broadcast domain and collision domain. or explain broadcast domain and collision domain. Broadcast domain is related to communicate data in another network , it is related with Network layer (IIIrd layer of osi model) , means from single point of network u can broadcast packets to many clients on another netwrok. Collision domain is can be in your same network , switches are producing collision domain breakup , because each port of swith is capable for collision domain breakup.

Routing protocol administrative Distance

RIP --> 120 IGRP -- ? 110 ospf --> 90 CONNECTED INTERFACE --> 0 STATIC ROUTE --> 1 IS-IS --> 115

INTERNAL EIGRP --> 90 EXTERNAL EIGRP -->? 170 EXTERNAL BGP --> 20 INTERNAL BGP --> 200

RIP V1 does not support VLSM EIGRP is based on distance vector algorithm. it is work based on min bw and net delay along with possible path. In the EIGRP routing info will exchange when route have change. Normally HELLO packet only exchange.

Passive Interface:

In RIP interface pasive make it will receive routing info, but not send. IN EIGRP will not send and receive routing info.

EIGRP

It is cisco preparatory protocol. You can only use it in an all-Cisco network, but EIGRP more than makes up for this deficiency by being easy to configure, fast, and reliable. The EIGRP metric is based on the minimum bandwidth and net delay along each possible path, which means that EIGRP can accommodate larger networks than RIP EIGRP uses a more sophisticated algorithm called Diffusing Update Algorithm (DUAL). The DUAL algorithm ensures that every router can individually make sure that its routing table is always free from loops. The EIGRP topology database on each router keeps track of higher cost candidates for the same destinations. This helps routing tables throughout the network to reconverge quickly after a topology change such as a link or router failure. EIGRP only distributes information about routes that have changed, and only when there is a change to report .The rest of the time, routers only exchange small "Hello" packets to verify that routing peers are still available. So EIGRP uses very little bandwidth Routers exchange routing information using multicast packets, which helps to limit bandwidth usage on segments that hold many routers EIGRP uses multicast address 224.0.0.10, sending packets as raw IP packets using protocol number 88.

which is a central feature of the DUAL algorithm. Every time a router receives a new piece of routing information from one of its neighbors, it updates the topology table. This helps to give it a reliable and up-to-date image of all of the connections in the network that are currently in use. EIGRP includes many of the features such as Classless Inter-Domain Routing (CIDR) and Variable Length Subnet Masks (VLSM) that are needed in larger networks. Router1(config)#router eigrp 55 The only restriction is that all of the routers that will be exchanging interior routing information via EIGRP must be configured with the same process number. The show ip route eigrp command lists the routes that have been learned through EIGRP EIGRP uses an RTP that guarantees delivery. It is Cisco Proprietary Protocols and distace vector routing technology that incorporate the best feature of link state routing but remains fully compatible with IGRP EIGRP incoporates the Diffusing Update Algorithem (DUAL) , which is the decision making process for all route compuations. A router running EIGRP stores all feasible routes (MAX 6) to a destination in its topology table. This allows it to switch quckly to an alternative route whenever there is a networkchanges. If EIGRP cannot find an alternative route locally, it queries its neighbours to discover a route. It uses Protocol dependent Modules (PDMs) as the mechanism for providing support for different routing protocol at the network layer. EIGRP periodically sending small hello packets, router can learn of other routers on their directly attached networks EIGRP is a classless routing protocol that advertises a route mask for every destination network. EIGRP uses multicast and unicast packets, rather than broadcasts for operational traffic When changes occur in a route, EIGRP sends partial routing updates rather than complet routing table. EIGRP uses multicast and unicast packets, rahter than broadcast for operatonal traffic. EIGRP support route summarization at class full network boundaries by default. EIGRP supports supernetting or the aggreation of blocks of address It also permits route redistribution between domains at the process level EIGRP and IGRP use the same algorithem to calculste a routing metirc EIGRP allows you to create summary routes at arbitrary network boundaries. EIGRP is capable of load balancing traffic over routers that have different metric values, which enables better traffic flow distribution. EIGRP operates at the Transport layer of the OSI reference model . eigrp 88 tcp 6 and upd 17 EIGRP supports multiaccess, point to point and non broadcast multiaccess (NBMA) topologies

EIGRP enables you to implement a hierarchical network design. EIGRP provides link to link protocol level security to avoid unauthorized access to routing table Eigrp have Neighbor table , topology table , routing table and successor and feasible sucessor table An Eigrp topology table contains all router advertised by neighboring routers. DUAL maintains a separate table for each configured routing protocol. It is select best route The best route to a destination is known as the successor to the destination. EIGRP support five Generic packet types Hellow, update, queries, replies, ack Smooth round trip timer (SRTT) The Retrasmit interval (RTO) is calculated on the basis of the SRTT value. EIGRP use the Reliable Tranport Protocol (RTP) to guarantee ordered delivery of packets to all neighbors. Only those packets that require explicit ack - Query, replay and update packets are transmitted reliably using RTP. RTP is responsible for ensuring the a router can still communicate with its established neighbors. RTP will retansmit an update query or replay packet up to 16 times in an attemnt to recive ack for the packet. If no ack is recieved after the retry limit is reached, the neighbor relationship is reset. EIGRP select a max of 6 primary (Sucessor) and backup (Feasible sucessor) routes per destinaiton. EIGRP metrix calculate is based on K values K1 -> Bandwidth, K2 ---> load, K3 -> Delay k4 -> Reliablity and K5 -> MTU While IGRP uses 24 bit to represet the composite metrix, EIGRP uses 32 bits DUAL determines the lowest cost route by adding the advertised distace (AD) between the next hope router and the destination to the cost between the local router an d the next hop router.The total cost is called the feasible distance (FD) EIGRP supports multiple sucessors to the same destinaiton provided they have the same FD use different next hop routers. All secussors are stored in the routing table.

Filtering Routes with EIGRP

You can filter the routes that EIGRP receives on a particular interface (or subinterface) using the distribute-list in command Router2#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router2(config)#access-list 34 deny 192.168.30.0 Router2(config)#access-list 34 permit any Router2(config)#router eigrp 55 Router2(config-router)#distribute-list 34 in / OUT Serial0.1 Router2(config-router)#end Disabling EIGRP on an Interface

Router1(config-router)#passive-interface Serial0/1 The passive-interface command in EIGRP prevents directly connected routers from establishing an EIGRP neighbor relationship EIGRP Route Summarization Router1(config-subif)#ip summary-address eigrp 55 172.25.0.0 255.255.0.0 Router1(config-router)#no auto-summary Summarization is one of the most powerful features of EIGRP, and one of the most frequently overlooked ways to improve network efficiency. OSPF can only summarize at the ABR. Adjusting Timers Router1(config-subif)#ip hello-interval eigrp 55 3 Router1(config-subif)#ip hold-time eigrp 55 9 EIGRP, you can adjust the timers on one router on a link independently of what you have configured on other interfaces on this router, or on other routers on this link. The default timer values for most interface types are 5 seconds for hellos and a 15-second hold timer.

Enabling EIGRP Authentication You want to authenticate your EIGRP traffic to ensure that no unauthorized equipment can affect your routing tables. Router1(config-if)#ip authentication mode eigrp 55 md5 Router1(config-if)#ip authentication key-chain eigrp 55 ORA They just authenticate these packets using MD5. Logging EIGRP Neighbor State Changes Router1(config)#router eigrp 55 Router1(config-router)#eigrp log-neighbor-changes Limiting EIGRP's Bandwidth Utilization You want to limit the fraction of an interface's bandwidth available to EIGRP for routing updates. Router1(config)#interface Serial0.1 Router1(config-subif)#ip bandwidth-percent eigrp 55 40 EIGRP Stub Routing

You want to stabilize your network by sending smaller routing tables out to stub branches and reducing the scope of EIGRP queries Router1(config)#router eigrp 55 Router1(config-router)#eigrp stub It is most commonly used in hub-and-spoke network designs, The eigrp stub command can take four different keywords: Receive-only : The router becomes a receive-only neighbor. This router will not share its routing information with its neighbors. Connected : This router will only advertise connected networks. Note that you must configure the appropriate network statements for these connected networks, or alternatively use the redistribute connected command. Static : The router will advertise static routes. Note that with this option you must also configure the redistribute static command. Summary : The router will advertise summary routes. This function is enabled by default. for details on route summarization.

Principle of EIGRP

Advanced distanced vector Loop free classless routing protocol Incremental update Load balancing across equal and unequal cost pathways It is work on auto summarizations and manual summarizations Rapid convergence Manual summarization at any point in the internet work. Automatically established neighbor relationship. It is work on Network layer It is use 50 % of BW by default. EIGRP uses the BW which are directly added in the neighbor router.

EIGRP (Transport Mechanism)

EIGRRP transport mechanisam has window size of one. Each packet must be ack. Retransmission happen 16 times Hello time is 5 sec - LAN Environment Hold time 15 sec LAN Environment

Hello time is 60 Sec WAN Environment. Hold time 180 Sec - WAN Environment. Hold time by default is three times the hello times

EIGRP DUAL

Track all routing advertised by neigboures Loop free path using a successor and remember any feasibility successor DUAL is a formal that uses a discovery path of loop free calculation. converge Kind of Packet in EIGRP

Hellow, Ack are unreliable Query , update and Replay are reliable packet.

EIGRP Terminology

Neighbor : A router running EIGRP that is directly connected

Route Table : The routing table or list of available network and the best path. A path is moved from topology table to the routing table when a feasible successor is identified.

Topology Table : A table that contains all the paths advertised by neighbours to all the know networks. This is list of all the successor , feasible successor, the feasible distance , the advertised distance and the outgoing interfaces.

Hello: Messages used to find and maintain neigbours in the topology table.

Update : An EIGRP packet containing changes information about the network. It is relable. It is send only when there is changes in the network to affected router.

Query : Send from the router when it loses a path to a network. If there is no alternate route (feasible successor) , it will send out queries to neighbors inquiring whether they have any feasible successor. This make the route state change to active. It is relable.

Smooth round Trip Time ( SRTT) : The time that the router waits after sending a packet reliably to hear the acknowledge.

Retransmission Timeout (RTO) : RTO determine how long the router waits for the ACK before retransmitting the packet.

Reliable Transport Protocol (RTP ) : Mechanism used to determine requirements that the packets be delivered in sequence and guranteed. Advertised distance : The cost of the path to the remote network from the neighbor. Feasible Distance : The lowest cost distance to a remote network.

Successor : The next hop router that passes the FC. It is chosen from the FS as having the lowest metric to the remote network. Stuck in Active (SIA) : When a router has sent out network packets and is Waiting for ACK from all neighbors. The router is active until all the ACK have Have been received. If they do not appear after a certain time, the route is SIA for router. the

Query Scoping : Network design to limit of the query range, that is , how far the Query is allowed to propagate in search of a feasible successor. This is necessary Prevent SIA.

Active: Router state when there is a network changes, but after examining the Topology table, no FS is found. The route is set to active mode

Passive : An operational route is passive. If the path is lose, the router examines The topology table to find the FS, If there is an FS, it is placed on routing table,

Other wise the route queries the neghbours and routes into active mode. Advertised distance : The EIGRP metric for an EIGRP neighbor to reach a priticula network

RTP: EIGRP uses both multicast and unicast addressing . Some of the packet are send relably. Update , query and replay packets are must be ack by the receving neighbor . the packet are retransmitted up to 16 times.

Stub Router It is used on hub and spoke environment. The stub router is EIGRP is similar to On Demand routing (ODR) No routing protocols are run on stub router. Stub router in EIGRP network use EIGRP to send limited info between the stub router and the core router.

This article discusses the known TCP/IP ports (TCP and/or UDP) that are used by Citrix services. Information Function Ports

ICA (Default) IMA CMC SSL STA (IIS)

TCP: 1494 TCP: 2512 TCP: 2513 TCP: 443 TCP: 80

TCP Browsing XML (Default) Citrix License Management Console Presentation Server Licensing ICA session w/ Session Reliability enabled

UDP: 1604 TCP: 80 TCP: 8082 TCP: 27000 TCP: 2598

What are 10Base2, 10Base5 and 10BaseT Ethernet LANs 10Base2An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments. 10Base5An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with 5 continuous segments not exceeding 100 meters per segment. 10BaseTAn Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling and twisted pair cabling. BOOTP helps a diskless workstation boot. How does it get a message to the network looking for its IP address and the location of its operating system boot files BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from a server that gives it the IP address. The same message might contain the name of the machine that has the boot files on it. If the boot image location is not specified, the workstation sends another UDP message to query the server.

Explain a DNS resource record A resource record is an entry in a name server's database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.

What protocol is used by DNS name servers DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP.

Explain the difference between interior and exterior neighbor gateways Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.

Explain the HELLO protocol used for The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

What are the advantages and disadvantages of the three types of routing tables The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every time there is a change. A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance. A fixed central table lets a manager modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine's table, as with the fixed table. Usually a dynamic table causes the fewest problems for a network administrator, although the table's contents can change without the administrator being aware of the change.

Explain source route It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.

Explain RIP (Routing Information Protocol) It is a simple protocol used to exchange information between the routers.

Explain SLIP (Serial Line Interface Protocol) It is a very simple protocol used for transmission of IP datagrams across a serial line. Explain Proxy ARP It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router. Explain OSPF It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet's topology to make accurate routing decisions. Explain Kerberos It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files. Explain a Multi-homed Host It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.

Explain NVT (Network Virtual Terminal) It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session. Explain Gateway-to-Gateway protocol It is a protocol formerly used to exchange routing information between Internet core routers. Explain BGP (Border Gateway Protocol) It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol). Explain autonomous system It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol. Explain EGP (Exterior Gateway Protocol) It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system. Explain IGP (Interior Gateway Protocol) It is any routing protocol used within an autonomous system Explain Mail Gateway It is a system that performs a protocol translation between different electronic mail delivery protocols. Explain multicast routing Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing. Explain packet filter Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped. Explain virtual path Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path. Explain virtual channel Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit

Explain logical link control One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection. Why should you care about the OSI Reference Model It provides a framework for discussing network operations and design. Explain the difference between routable and non- routable protocols Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router Explain MAU In token Ring , hub is called Multistation Access Unit(MAU). Explain 5-4-3 rule In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated. Explain the difference between TFTP and FTP application layer protocols The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP. The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information. Explain the range of addresses in the classes of internet addresses Class A 0.0.0.0 - 127.255.255.255 Class B 128.0.0.0 - 191.255.255.255 Class C 192.0.0.0 - 223.255.255.255 Class D 224.0.0.0 - 239.255.255.255 Class E 240.0.0.0 - 247.255.255.255 Explain the minimum and maximum length of the header in the TCP segment and IP datagram The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes. Explain difference between ARP and RARP The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver. The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its

physical address. Explain ICMP ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages What are the data units at different layers of the TCP / IP protocol suite The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media. Explain Project 802 It is a project started by IEEE to set standards that enable intercommunication between equipment from a variety of manufacturers. It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for interconnectivity of major LAN protocols. It consists of the following: 802.1 is an internetworking standard for compatibility of different LANs and MANs across protocols. 802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is nonarchitecture-specific, that is remains the same for all IEEE-defined LANs. Media access control (MAC) is the lower sublayer of the data link layer that contains some distinct modules each carrying proprietary information specific to the LAN product being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5). 802.6 is distributed queue dual bus (DQDB) designed to be used in MANs. Explain Bandwidth Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth. Difference between bit rate and baud rate. Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits. baud rate = bit rate / N where N is noof-bits represented by each signal shift. Explain MAC address The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique. Explain attenuation The degeneration of a signal over distance on a network cable is called attenuation.

Explain cladding A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable. Explain RAID A method for providing fault tolerance by using multiple hard disk drives. Explain NETBIOS and NETBEUI NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications. NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets. Explain redirector Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer Explain Beaconing The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks. Explain terminal emulation, in which layer it comes Telnet is also called as terminal emulation. It belongs to application layer. Explain frame relay, in which layer it comes Frame relay is a packet switching technology. It will operate in the data link layer. What do you meant by "triple X" in Networks The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X" Explain SAP Series of interface points that allow other computers to communicate with the other layers of network protocol stack. Explain subnet A generic term for section of a large networks usually separated by a bridge or router. Explain Brouter Hybrid devices that combine the features of both bridges and routers.

How Gateway is different from Routers A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats. What are the different type of networking / internetworking devices Repeater: Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link. Bridges: These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion. Routers: They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission. Gateways: They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model. Explain mesh network A network in which there are multiple network links between computers to provide multiple paths for data to travel Explain passive topology When the computers on the network simply listen and receive the signal, they are referred to as passive because they dont amplify the signal in any way. Example for passive topology - linear bus. What are the important topologies for networks BUS topology: In this each computer is directly connected to primary network cable in a single line. Advantages: Inexpensive, easy to install, simple to understand, easy to extend. STAR topology: In this all computers are connected using a central hub. Advantages: Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems. RING topology: In this all computers are connected in loop. Advantages:

All computers have equal access to network media, installation can be simple, and signal does not degrade as much as in other topologies because each computer regenerates it. What are major types of networks and explain Server-based network Peer-to-peer network Peer-to-peer network, computers can act as both servers sharing resources and as clients using the resources. Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration Explain difference between baseband and broadband transmission In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously. What are the possible ways of data exchange (i) Simplex (ii) Half-duplex (iii) Full-duplex. What are the types of Transmission media Signals are usually transmitted over some transmission media that are broadly classified in to two categories. Guided Media: These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light. Unguided Media: This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony. Explain point-to-point protocol A communications protocol used to connect computers to remote networking services including Internet service providers. What are the two types of transmission technology available (i) Broadcast and (ii) point-to-point

Difference between the communication and transmission. Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc. Communication means the meaning full exchange of information between two communication media

Cisco Switch VLAN Trunking Protocol VLAN Trunking Protocol (VTP) is a Cisco Layer 2 messaging protocol that manages the addition, deletion, and renaming of VLANs on a network-wide basis. Virtual Local Area Network (VLAN) Trunk Protocol (VTP) reduces administration in a switched network. When you configure a new VLAN on one VTP server, the VLAN is distributed through all switches in the domain. This reduces the need to configure the same VLAN everywhere. VTP is a Cisco-proprietary protocol that is available on most of the Cisco Catalyst Family products. VTP ensures that all switches in the VTP domain are aware of all VLANs. All Cisco Catalyst switches are configured to be VTP servers.

Modes of Operation Server In VTP server mode, you can create, modify, and delete VLANs and specify other configuration parameters (such as VTP version and VTP pruning) for the entire VTP domain. VTP servers advertise their VLAN configuration to other switches in the same VTP domain and synchronize their VLAN configuration with other switches based on advertisements received over trunk links. VTP server is the default mode. Transparent VTP transparent switches do not participate in VTP. A VTP transparent switch does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received advertisements. However, in VTP version 2, transparent switches do forward VTP advertisements that they receive out their trunk ports. Client VTP clients behave the same way as VTP servers, but you cannot create, change, or delete VLANs on a VTP client. Upon receipt of an advertisement request, a VTP device sends a summary advertisement, followed by one or more subset advertisements.

What is bandwidth aggregation? The use of multiple modems to achieve aggregate bandwidth equivalent to broadband solutions is both available and affordable to most users today. The amount of time it takes to download web pages or other information from the Internet depends on a number of factors including Internet access bandwidth limitations, ISP performance restrictions, general Internet congestion and remote host response time. Often, the weakest link in this chain is the bandwidth between your computer and the Internet, also known as Internet access bandwidth. To many Internet users, increasing this bandwidth involves getting a broader bandwidth connection, sometimes at considerable expense. If no low cost broadband alternative is available in your area, the only way forward from a 56Kbps modem is ISDN or leased line. Both of these alternatives can be very costly. It is possible however to have more than one connection between your computer and the Internet, and to combine them to accumulate bandwidth. Techniques that accomplish this task are collectively referred to in this document as "bandwidth aggregation". Although bandwidth aggregation may occur in many different contexts, the scope of this document is limited to the aggregation of Internet access bandwidth. Two techniques will be examined in detail, Multilink and Connection Teaming. What is bonding? Data is broken up into manageable packets for Internet delivery. Multiple bonded connections behave like a single connection. Suppose for example that a web server sends an image to a web browser. This image would be broken up into several packets by the server operating system because a single packet would be much too large for routers and network components to handle. a) Web server sends image to web browser. b) TCP stack on web server computer breaks data into packets for delivery. c) Packets are delivered to web browser over bonded link. d) TCP stack on web browser computer reassembles packets into image. e) Web browser displays image. If part of the route between the server and the browser were composed of bonded multiple links, the packets that made up the image could alternately travel over one or the other of the component links. Neither the web server nor the web browser would be aware of this. From a functional point of view there is only one link. The component links are said to be bonded. 3. What is PPP Multilink? PPP Multilink can give you aggregate bandwidth equal to the sum of the individual physical connections. The PPP Multilink Protocol (MP) is an extende