cis 82 routing protocols and concepts

5/27/2018 CIS 82 Routing Protocols and Concepts

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Chapter 1

Introduction to Routing andPacket Forwarding

CIS 82 Routing Protocols and Concepts

Rick GrazianiCabrillo College

[email protected]

Last Updated: 2/16/2009


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This Presentation

For detai led inform ation see the notes sect ion w ithin thisPowerPoint.

This presentation is based on the Exploration course/book, Routing

Protocols and Concepts.

For a copy of this presentation and access to my web site for other

CCNA, CCNP, and Wireless resources please email me for ausername and password.

Email: [email protected]

Web Site: www.cabrillo.edu/~rgraziani


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Note

This chapter contains mostly introductory material.

Most of not all of this information will be explained in more detailin later chapters or later courses.

The bootup process and the IOS are examined in a later

course.

Do notworry or focus too much on the details for now.

This will all be examined and explained in the following chapters.


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For further information

This presentation is an

overview of what iscovered in thecurriculum/book.

For further explanationand details, please readthe chapter/curriculum.

Book:

Routing Protocolsand Concepts

By Rick Graziani andAllan Johnson

ISBN: 1-58713-206-0

ISBN-13: 978-58713-206-3


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Topics

Inside the Router

Routers are computers

Router CPU and Memory

Internetwork OperatingSystem

Router Bootup Process

Router Ports and Interfaces Routers and the Network

Layer

Path Determination andSwitching Function

Packet Fields and Frame

Formats Best Path and Metrics

Equal Cost Load Balancing

Path Determination

Switching Function

CLI Configuration and

Addressing

Implementing BasicAddressing Schemes

Basic Router

Configuration

Building the Routing Table

Introducing the RoutingTable

Directly Connected

Networks

Static Routing

Dynamic Routing

Routing Table Principles


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Inside the Router

Routers are computers

Router CPU and Memory

Internetwork Operating System

Router Bootup Process

Router Ports and Interfaces

Routers and the Network Layer


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Routers are Computers

A router is a computer:

CPU, RAM, ROM, Operating System The first router: used for the Advanced Research Projects Agency

Network (ARPANET):

IMP (Interface Message Processor)

Honeywell 516 minicomputer that brought the ARPANET to life

on August 30, 1969.

Leonard Kleinrock and the first IMP.


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Routers forwarding packets (packet switching):

From the original sourceto the final destination.

Selects best pathbased on destination IP address

A router connects multiple networks:

Interfaces on different IP networks


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Router interfaces:

LAN

WAN


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Routers Determine the Best Path

The routers primary responsibility:

Determining the best path

Forwarding packetstoward their destination


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Routers Determine the Best Path

Routing table

Determines best path.

Best match between destination IP addressand networkaddress in routing table

IP Packet enters routers Ethernet interface.

Router examines the packets destination IP address.

Router searches for a best match between packets destination IP address and

network address in routing table.

Using the exit-interface in the route, the packet is forwarded to the next router orthe final destination.


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Router

CPU and

Memory

CPU- Executes operating system instructions

Random access memory (RAM)

running copy of configuration file

routing table ARP cache

Read-only memory (ROM)

Diagnostic software used when router is powered up.

Routers bootstrap program

Scaled down version of operating system IOS

Non-volatile RAM (NVRAM) Stores startup configuration. (including IP addresses, Routing protocol)

Flash memory- Contains the operating system (Cisco IOS)

Interfaces- There exist multiple physical interfaces that are used to connectnetwork. Examples of interface types:

Ethernet / fast Ethernet interfaces

Serial interfaces Mana ement interfaces


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Router physical characteristics


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Cisco IOS - Internetwork

Operating System

Responsible for managing the hardware and softwareresources: Allocating memory

Managing processes

Security

Managing file systems

Manydifferent IOS images. An IOS image is a file that contains the entire IOS for that router.

Routermodel

IOS features

Example IPv6or a routing protocol such as Intermediate System

toIntermediate System (IS-IS).


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Router Bootup Process (more in later course)


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Bootup Process

running-config

IOS (running)

startup-config IOS

ios (partial)

Bootup program


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running-config

IOS (running)

startup-config IOS

ios (partial)

Bootup program

Where is the permanent configuration file stored used during boot-up? NVRAM

Where is the diagnostics software stored executed by hardware modules? ROM

Where is the backup (partial) copy of the IOS stored? ROM

Where is IOS permanently stored before it is copied into RAM? FLASH

Where are the bootsystem commands stored which are used to locate

the IOS?NVRAM


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running-config

IOS (running)

startup-config IOS

ios (partial)

Bootup program

?

?

?

?

?

?

?


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running-config

IOS (running)

startup-config IOS

ios (partial)

Bootup program

startup-config

IOS

Bootup program

ios (partial)

running-config

IOS (running)


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1. ROM1. POST

2. Bootstrap code executed

3. Check Configuration Register value (NVRAM)

0 = ROM Monitor mode

1 = ROM IOS

2 - 15 = startup-config in NVRAM

2. Check for IOS boot system commandsin startup-config file (NVRAM)If boot system commands in startup-config

a. Run boot system commands in order they appear in startup-config to locate the IOS

b If boot system commands fail, use default fallback sequence to locate the IOS (Flash, TFTP, ROM)

3. Locate and load IOS, Default fallback sequence: No IOS boot system commands in startup-config

a. Flash (sequential)

b. TFTP server (netboot) - The router uses the configuration register value to form a filename from

which to boot a default system image stored on a network server.c. ROM (partial IOS) or keep retrying TFTP depending upon router model

- If no IOS located, get partial IOS version from ROM

4. Locate and load startup-configconfiguration

a. If startup-config found, copy to running-config

b. If startup-config not found, prompt for setup-mode

c. If setup-mode bypassed, create a skeleton default running-config (no startup-config)

Router Boot Process

Details (later)


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Verify the router boot-up process show versioncommand is used to view information about the

router during the bootup process (later).


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Ports and Interfaces

Port- normally means one of the management ports used foradministrative access

Interfacenormally refers to interfaces that are capable of sendingand receiving user traffic.

Note: However, these terms are often used interchangeably in theindustry and even with IOS output.


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Management

Ports

Console port

Terminal

PC running terminal emulator software

No need for network access

Used for initial configuration

Auxiliary (AUX) port

Not all routers have auxiliary ports.

At times, can be used similarly to a console port

Can also be used to attach a modem.

Note:Auxiliary ports will not be used in this curriculum.


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Router Interfaces

Interfaces- Receive and forward packets.

Various types of networks

Different types of media and connectors.

Different types of interfaces.

Fast Ethernetinterfaces - LANs

Serial interfaces- WANconnections including T1, DSL, and ISDN


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Router Interfaces

Router Interface:

Different network

IP address and subnet maskof thatnetwork

Cisco IOS wil l not al low tw o act ive interfaces on the same

router to belong to the same network .

FastEthernet 0/0

MAC: 0c00-3a44-190a

192.168.1.1/24

FastEthernet 0/0

MAC: 0c00-41cc-ae12

10.1.0.1/16

Serial 0/0

172.16.1.1/24

Serial 0/1

172.16.1.2/24


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LAN Interfaces

Ethernet and Fast Ethernet interfaces

Connects the router to the LAN

Layer 2MAC address Participates in the Ethernet

Address Resolution Protocol (ARP):

Maintains ARP cache for that interface

Sends ARP requests when needed

Responds with ARP replies when required

Typically an RJ-45 jack (UTP).

Router to switch: straight-through cable

Router to router: crossover cable


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WAN Interfaces

Point-to-Point, ISDN, and Frame Relay interfaces

Connects routers to external networks. The Layer 2 encapsulation can be different types including:

PPP

Frame Relay

HDLC (High-Level Data Link Control).

Note: MAC addresses are used only on Ethernet interfaces and are

not on WAN interfaces.

Layer 2 WAN encapsulation types and addresses are covered in a

later course.


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Routers at

theNetwork

Layer

Layer 3 devicebecause its primary forwardingdecision is based on the information in the Layer 3 IP

packet (destination IP address).

This is known as rout ing.


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Routers Operate at Layers 1, 2, and 3


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Path Determination and

Switching Functions

Packet Fields and Frame Formats

Best Path and Metrics

Equal Cost Load BalancingPath Determination

Switching Function


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Path Determination and Switching Functions

The following sections focus on exactly what happens to data as it

moves from source to destination.

Review the packet and frame field specifications

Discuss in detail how the frame fields change from hop to hop,

whereas the packet fields remain unchanged


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Ethernet Frame

Layer 2 addresses:

Interface-to-Interface on the same network.

Changes as packet is decapsulated and encapsulated from

network to network Layer 3 addresses:

Original source layer 3 address (IP)

Final destination layer 3 address (IP)

Does not change (except with NAT, but this is not a concern of

IP but an internal network process)

IPv4 (Internet

Protocol)


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Best Path

Routers best-path to a network:

optimum or shortest path

Routing protocol dependent

Dynamic routing protocolsuse their own rulesand metr ics.

A metricis the quantitative value used to measure the distance to agiven route.

The best pathto a network is the path with the lowest metric.

Example, a router will prefer a path that is one hop away over a path

that is two hops away.


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Best Path

1.5 Mbps

1.5 Mbps

Comparing Dynamic Routing Protocols: RIP and OSPF

RIPuses hop coun t

R1 to R3

Fewer links but much slower

OSPFuses bandwidth

R1 to R2 to R3

More routers but much faster links


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What happens if a routing table has two or

more paths with the same metric to the samedestination network? (equal-cost metric)

Router will perform equal-cost load balancing.

Equal CostLoad

Balancing

?

?

To reach the 192.168.1.0/24

network it is 2 hops via R2 and 2

hops via R4.

192.168.1.0/24


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Equal-Cost Paths

Versus Unequal-

Cost Paths

T1

T3

Can a router use multiple paths if the paths

(cost, metric) to reach the destination

network are not equal?

Yes, if the routers are using the EIGRProuting

protocol which supports unequal cost load

balancing.

192.168.1.0/24


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Path Forwarding

Packet forwarding involves two functions:

Path determination function

Switching function


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Path Forwarding

Path determinationfunction is the process of how the router determines

which path to use when forwarding a packet. To determine the best path, the router searches its routing table for a

network address that matches the packets destination IP address.

One of three path determinations results from this search:

Directly connected network

Remote network

No route determined

Directly connected

network

Router receives packet.

Destination IP address matches a network on one

of its directly connected networks.

Packet is forwarded outthat network.


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Path Forwarding






Remote network

No route determined

Remote

network


Destination IP address matches a remote network

which can only be reached via another router.

Packet is forwarded out thatnetwork to the next-hop router.


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Path Forwarding






Remote network

No route determined


Destination IP address does NOT match any

network in the routers routing table.

Packet is dropped.

No route

determined

Does this mean the network does not

exist?No, only that the router does not know

about that network. (later)


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Path Forwarding

Switching functionis the process used by a router to:

Accept a packet on one interface and

Forward it out another interface

A key responsibility of the switching function is to encapsulatepackets in the appropriate data-link frame type for the outgoing data

link.

192 168 4 10


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What does a router do with a packet received from one network and destined for anothernetwork?

1. Decapsulates the Layer 3 packet by removing the Layer 2 frame header and trailer

2. Examines the destination IP address of the IP packet to find the best path in therouting table

3. Encapsulates the Layer 3 packet into a new Layer 2 frame and forwards the frame

out the exit interface

Dest. MAC

0B-31

Source MAC

00-20

Type

800

Trailer

Layer 2 Data Link Frame

Dest. IP

192.168.4.10

Source IP

192.168.1.10

IP

fields

Data

Layer 3 IP Packet

Dest. MAC

00-10

Source MAC

0A-10

Type

800

Trailer

Path

Forwarding192.168.1.10

192.168.4.10


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Remember: Encapsulation

Now, lets do an example

Destination IP

Address

Source IP

Address

Other IP

fields

Data

Destination

Address

Source

Address

Type Data Trailer

Layer 3 IP Packet


CurrentData Link

Address of Host or

Routers exit interfaceNext hopData

Link Address ofHost or Routers

interface

These change from

host to router, router to

router, and router to

host.

These addresses

do notchange!


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This is just a summary.

Thedetails will be shown next! Now for the details

Dest. MAC00-10

Source MAC0A-10

Type800

Trailer


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

Dest. MAC0B-31

Source MAC00-20

Type800

TrailerDest. IP192.168.4.10

Source IP192.168.1.10

IPfields

DataDest. AddFF-FF

Source Add Type800

Trailer


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From Host X to Router RTA

Host X begins by encapsulating the IP packet into a data link frame (in thiscase Ethernet) with RTAs Ethernet 0 interfaces MAC address as the datalink destination address.

How does Host X know to forward to packet to RTA and not directly to HostY?

IP Source and IP Destination Addresses are on different networks

How does Host X know or get RTAs Ethernet address? Checks ARP Table for Default Gateway IP Address and associated

MAC Address.

What if it there is not an entry in the ARP Table?

Host X sends an ARP Request and RTA sends an ARP Reply

Dest. MAC

00-10

Source MAC

0A-10

Type

800

Trailer


Dest. IP

192.168.4.10

Source IP

192.168.1.10

IP

fields

Data

Layer 3 IP Packet


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RTA

1. RTA examines Destination MAC address, which matches the E0 MAC address, so it copies in theframe.

2. RTA sees the Type field is 0x800, IP packet in the data field, a packet which needs to be routed.

3. RTA strips off the Ethernet frame.

RTA looks up the Destination IP Addressin its routing table.

192.168.4.0/24 has next-hop-ip address of 192.168.2.2 and an exit-interface of e1. Since the exit interface is on an Ethernet network, RTA must resolve the next-hop-ip address with a

destination MAC address.

4. RTA looks up the next-hop-ip address of 192.168.2.2 in its ARP cache.

If the entry was not in the ARP cache, the RTA would need to send an ARP request out e1. RTBwould send back an ARP reply, so RTA can update its ARP cache with an entry for 192.168.2.2. 5.Packet is encapsulated into a new data link (Ethernet) frame.

Dest. MAC0B-31

Source MAC00-20

Type800

Trailer


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

RTA Routing Table

Network Hops Next-hop-ip Exit-interface

192.168.1.0/24 0 Dir.Conn. e0

192.168.2.0/24 0 Dir.Conn e1

192.168.3.0/24 1 192.168.2.2 e1192.168.4.0/24 2 192.168.2.2 e1

RTA ARP Cache

IP Address MAC Address

192.168.2.2 0B-31

Dest. MAC00-10

Source MAC0A-10

Type800

Trailer


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RTB

1. RTB examines Destination MAC address, which matches the E0 MAC address, and copies in the frame.

2. RTB sees Type field, 0x800, IP packet in the data field, a packet which needs to be routed.

3. RTB strips off the Ethernet frame.

RTB looks up the Destination IP Addressin its routing table.

192.168.4.0/24 has next-hop-ip address of 192.168.3.2 and an exit-interface of Serial0.

Since the exit interface is notan Ethernet network, RTB does nothave to resolve the next-hop-ip addresswith a destination MAC address.

When the interface is a point-to-point serial connection, (like a pipe), RTB encapsulates the IP packet intothe proper data link frame, using the proper serial encapsulation (HDLC, PPP, etc.).

The data link destination address is set to a broadcast(theres only one other end of the pipe).

5. Packet is encapsulated into a new data link (serial, PPP) frame and sent out the link.

Dest. AddFF-FF

Source Add Type800

Trailer


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

RTB Routing Table


192.168.1.0/24 1 192.168.2.1 e0

192.168.2.0/24 0 Dir.Conn e0

192.168.3.0/24 0 Dir.Conn s0

192.168.4.0/24 1 192.168.3.2 s0

Dest. MAC0B-31

Source MAC00-20

Type800

Trailer


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RTC

1. RTC copies in the data link (serial, PPP) frame.

2. RTC sees the Type field is 0x800, IP packet in the data field, a packet which needs to be routed.

3. RTC strips off the data link, serial, frame.

RTC looks up the Destination IP Addressin its routing table. RTC realizes that this Destination IP Address is on the same network as one of its interfaces and it can sent the packet

directly to the destination and not another router. Since the exit interface is on an directly connected Ethernet network, RTC must resolve the destination ip address with

a destination MAC address.

2. RTC looks up the destination ip address of 192.168.4.10 in its ARP cache.

If the entry was not in the ARP cache, the RTC would need to send an ARP request out e0. Host Y would send backan ARP reply, so RTC can update its ARP cache with an entry for 192.168.4.10.

5. Packet is encapsulated into a new data link (Ethernet) frame and sent out the interface.

Dest. MAC0B-20

Source MAC0C-22

Type800

Trailer


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

RTC ARP Cache

IP Address MAC Address

192.168.4.10 0B-20

RTC Routing Table


192.168.1.0/24 2 192.168.3.1 s0

192.168.2.0/24 1 192.168.3.1 s0

192.168.3.0/24 0 Dir.Conn s0192.168.4.0/24 0 Dir.Conn e0

Dest. AddFF-FF

Source Add Type800

Trailer


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Host Y

Layer 2: Data Link Frame1. Host Y examines Destination MAC address, which matches its Ethernet interface MAC address, and

copies in the frame.

2. Host Y sees the Type field is 0x800, IP packet in the data field, which needs to be sent to its IP process.

3. Host Y strips off the data link, Ethernet, frame and sends it to its IP process.

Layer 3: IP Packet

4. Host Ys IP process examines the Destination IP Addressto make sure it matches its own IP

Address.. If it does not, the packet will be dropped.

5. The packets protocol field is examined to see where to send the data portion of this IP packet: TCP,UDP or other?

Layer 4: TCP, UDP or other?


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

Dest. MAC0B-20

Source MAC0C-22

Type800

Trailer


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The summary once again!

Dest. MAC00-10

Source MAC0A-10

Type800

Trailer


Dest. IP192.168.4.10

Source IP192.168.1.10

IPfields

Data

Layer 3 IP Packet

Dest. MAC0B-31

Source MAC00-20

Type800

TrailerDest. IP192.168.4.10

Source IP192.168.1.10

IPfields

DataDest. AddFF-FF

Source Add Type800

Trailer


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CLI Configuration and

Addressing

Implementing Basic Addressing Schemes

Basic Router Configuration


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Learning IOS: Lab 1.5.2 (Cabrillo College Version)

Networking Lab NetLab Packet Tracer


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Establishing a HyperTerminal session (next week)

Take the following steps to connect a terminal to the console port on the router:

Connect the terminal using the RJ-45 to RJ-45 rollover cable and an RJ-45 to DB-9or RJ-45 to DB-25 adapter.

Configure the terminal or PC terminal emulation software for 9600 baud, 8 data bits,no parity, 1 stop bit, and no flow control.

Rollover cable

Console port

Com1 or Com2 serial port

Terminal or a

PC with

terminalemulation

software

Router


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Establishing a Terminal session

Important: A console connection is not the same as a network

connection!

=

Tera Term

HyperTerminal (comes with Windows)

Putty

When do you need to use a console connection to the router?


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Terminal Connection

No network connection needed ConsolePort

y

What software do you need?

What cable and ports do you use?

When there is not a network connection to the router (cant use telnet).

Tera Term, HyperTerminal, Putty, etc.

PC: Serial port & Router: Console PortRollover or Console Cable

Serial


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C:\> telnet

C:\> ping

Ethernet Connection

Network connection needed

When can you use a network connection to

the router?

What software/command do you need?

What cable and ports do you use?

When should you not use a network

connection to configure the router?

When there is a network connection to the

router (telnet).TCP/IP, Terminal prompt (DOS),

Tera Term, etc.

PC & Router: Ethernet NIC

Ethernet straight-through cable

When the change maydisconnect the telnet connection.

NIC


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Terminal Connection

No network connection needed ConsolePort

C:\> telnet

C:\> ping

Ethernet Connection

Network connection needed

Serial

NIC


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NetLab


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NetLab

Basic Router

Pod


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Your Interfaces may differ

R1# show ip interface brief

Interface IP-Address OK? Method Status ProtocolFastEthernet0/0 192.168.1.1 YES manual up up

FastEthernet0/1 192.168.1.2 YES manual up up

Serial0/0 192.168.2.1 YES manual up up

Serial0/1 unassigned YES manual up up

FastEthernet 0 = FastEthernet 0/0

FastEthernet 1 = FastEthernet 0/1 = FastEthernet 1/0

Serial 0 = Serial 0/0 = Serial 0/0/0

Serial 1 = Serial 0/1 = Serial 0/0/1


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Learning IOS: Lab 1.5.2 (Cabrillo College Version)


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Command Overview (partial list from lab)Router> user mode

Router> enable

Router# privilege mode

Router# configure terminal

Router(config)# exit

Router# config t

Router(config)# hostname name

Router(config)# enable secretpassword privilege passwordRouter(config)# line console 0 console password

Router(config-line)#passwordpassword

Router(config-line)# login

Router(config)# line vty 0 4 telnet password

Router(config-line)#passwordpassword

Router(config-line)# login

Router(config)#banner motd # message# banner

Router(config)# interfacetype number configure interface

Router(config-if)# ip addressaddress mask

Router(config-if)# descriptiondescription

Router(config-if)# no shutdown


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Other Commands

Router# copy running-config startup-config

Router# show running-config

Router# show ip route

Router# show ip interface brief

Router# show interfaces


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Different Modes

IOS commands must be entered in the correct mode.

Router#hostname R1

^% Invalid input detected at '^' marker.

Router# configure terminal

Router(config)# hostname R1

R1(config)#


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Serial Connectors

2500 have the older, larger serial interfaces

Later Cisco routers use the smart serial interfaces which allowsmore data to be forwarded across fewer cable pins.

Smart

Serial

Older

Serial


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Serial Connectors

Router is typically a DTE device.

The DTE cable is connected to the serial interface on the router to a

CSU/DSU device (DCE).

DTE Cable

DCE Cable


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WAN Interface Configuration

R1(config)# interface Serial0/0

R1(config-if)# ip address 192.168.2.1 255.255.255.0R1(config-if)#description Link to R2

R1(config-if)#clock rate 64000 DCE Only

R1(config-if)#no shutdown


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Unsolicited Messages from IOS

The IOS often sends unsolicited messages

Does not affect the command Can cause you to lose your place when typing.

R1(config)# interface fastethernet0/0

R1(config-if)# ip address 172.16.3.1 255.255.255.0R1(config-if)# no shutdown

R1(config-if)# descri

*Mar 1 01:16:08.212: %LINK-3-UPDOWN: Interface

FastEthernet0/0, changed state to up

*Mar 1 01:16:09.214: %LINEPROTO-5-UPDOWN: Line protocol onInterface

FastEthernet0/0, changed state to upption

R1(config-if)#


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Unsolicited Messages from IOS

To keep the unsolicited output separate from your input, enter lineconfiguration mode for the console port and add the loggingsynchronous

R1(config)# line console 0

R1(config-line)# logging synchronous

R1(config-if)# descri

*Mar 1 01:28:04.242: %LINK-3-UPDOWN: Interface


*Mar 1 01:28:05.243: %LINEPROTO-5-UPDOWN: Line protocol onInterface


R1(config-if)# description


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LAN Interface Configuration

R1(config)# interface FastEthernet0/0

R1(config-if)# ip address 192.168.1.1 255.255.255.0R1(config-if)# description R1 LAN

R1(config-if)# no shutdown

Fa0/1


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Each Interface Belongs to a Different Network

R1(config)# interface FastEthernet0/1

R1(config-if)# ip address 192.168.1.2 255.255.255.0192.168.1.0 overlaps with FastEthernet0/0

R1(config-if)# no shutdown

192.168.1.0 overlaps with FastEthernet0/0

FastEthernet0/1: incorrect IP address assignment

Fa0/1192.168.1.1/24

192.168.1.2/24

Same Network!


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Each Interface Belongs to a Different Network

R1# show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 192.168.1.1 YES manual up up

Serial0/0 192.168.2.1 YES manual up up

FastEthernet0/1 192.168.1.2 YES manual administratively

down down

Serial0/1 unassigned YES unset administratively

down down

Fa0/1

V if i I f


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Verifying Interfaces

R1# show interfaces

FastEthernet0/0is up, line protocol is up(connected)Hardware is Lance, address is 0007.eca7.1511(bia 00e0.f7e4.e47e)

Description: R1 LAN

Internet address is 192.168.1.1/24

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255

Encapsulation ARPA, loopback not set

ARP type: ARPA,ARP Timeout 04:00:00,

Last input 00:00:08, output 00:00:05, output hang never

Last clearing of show interface counters neverQueueing strategy: fifo

Output queue :0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

Serial0/0is up, line protocol is up(connected)

Hardware is HD64570

Description: Link to R2

Internet address is 192.168.2.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input never, output never, output hang never

V if R t C fi ti


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74

Verify Router Configuration

R1# show running-config

!

version 12.3

!

hostname R1

!

interface FastEthernet0/0

description R1 LAN

ip address 192.168.1.1 255.255.255.0

!

interface Serial0/0

description Link to R2

ip address 192.168.2.1 255.255.255.0

clock rate 64000

!

banner motd ^C

******************************************

WARNING!! Unauthorized Access Prohibited!!

******************************************

^C

!line con 0

password cisco

login

line vty 0 4

password cisco

login

!

end

Note: shutdownis the

default. no shutdowndoes

not show in the configuration.

S C fi ti


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75

Save Configuration

R1# copy running-config startup-config

R1#show startup-config

Using 728 bytes

!

version 12.3

!

hostname R1

!

interface FastEthernet0/0

description R1 LAN

ip address 192.168.1.1 255.255.255.0

!

interface Serial0/0

description Link to R2

ip address 192.168.2.1 255.255.255.0

clock rate 64000

!

banner motd ^C

******************************************

WARNING!! Unauthorized Access Prohibited!!

******************************************^C

line con 0

password cisco

login

line vty 0 4

password cisco

login

!

end


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Building the Routing Table

Introducing the Routing Table

Directly Connected Networks

Sh R ti T bl


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77

Show Routing Table

R1# show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set

C 192.168.1.0/24 is directly connected, FastEthernet0/0

C 192.168.2.0/24 is directly connected, Serial0/0

I t d i th R ti T bl


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Routing tableis a data file in RAM that is used to store route

information about: Directly connected networks

Remote networks

R1# show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set



I t d i th R ti T bl


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79


Directly connected interfaces contain the exit interface (more later)

R1# show ip route



Exit Interfaces



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80


directly connected networkis a network that is directly attached to one of

the router interfaces.

When a routers interface is configured with an IP address and subnet

mask, the interface becomes a host on that attached network.

Active directly connected networks are added to the routing table.

R1# show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP



Directly ConnectedNetworks



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81


A remote networkis a network that is notdirectly connected to the

router.

A remote network is a network that can only be reached by sendingthe packet to another router.

Remote networks are added to the routing table using: (later)

Dynamic routing protocol

Static routes

R1# show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP



Remote Network


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Chapter 1

Introduction to Routing and

Packet Forwarding

CIS 82 Routing Protocols and Concepts

Rick Graziani

Cabrillo College

[email protected]

cis 82 routing protocols and concepts

Documents

routing protocolsand

best path routing table

router routers

lanwan5272018 cis

destination5272018 cis

router interfaces

interfaces routers

computers router cpu