Ericsson IP Certification - Associate Level

IP routing Workshop

QUESTION 1Match the switching charateristics to the correct term.(Not all options are used)

Answer 1

QUESTION 2A small-sized company has 20 workstations and 2 servers. The company has been assigned a group of IPv4 addresses 209.165.200.224/29 from its ISP. What technology should the company implement in order to allow the workstations to access the services over the Internet?

A. static NATB. dynamic NATC. port address translationD. DHCPAnswer 2Answer: B

QUESTION 3Which three advantages are provided by static routing? (Choose three.)The path a static route uses to send data is known.No intervention is required to maintain changing route information.Static routing does not advertise over the network, thus providing better security. Static routing typically uses less network bandwidth and fewer CPU operations than dynamic routing does. Configuration of static routes is error-free.Static routes scale well as the network grows.Answer 3

Answer: A C D

QUESTION 4A network contains multiple VLANs spanning multiple switches. What happens when a device in VLAN 20 sends a broadcast Ethernet frame?

A. Only devices in VLAN 20 see the frame.B. Devices in VLAN 20 and the management VLAN see the frameC.Only devices that are connected to the local switch see the frame.D.All devices in all VLANs see the frame.

Answer 4Answer: A

QUESTION 5Assume that the routing protocol referenced in each choice below is configured with its default settings and the given routing protocol is running on all the routers. Which two conditional statements accurately state the path that will be chosen between networks 10.1.0.0 and 10.3.2.0 for the routing protocol mentioned? (Choose two)

QUESTION 5 (cont)If OSPF is the routing protocol, the path will be from R1 to R3 to R4 to R5.If OSPF is the routing protocol, the path will be from R1 to R2 to R5.If OSPF is the routing protocol, the path will be from R1 to R5.If RIPv2 is the routing protocol, the path will be from R1 to R3 to R4 to R5.If RIPv2 is the routing protocol, the path will be from R1 to R5.Answer 5Therefore if OSPF is used, it will choose the path R1 -> R3 -> R4 -> R5 because these links have much higher speed than other paths -> A is correct.First we need to know the speed of these links:+ T1: 1.544 Mbps+ 10BaseT: 10 Mbps+ 100BaseT (often referred to as FastEthernet): 100Mbps

OSPF chooses the best path via bandwidth while RIP only uses hop count (the sum of routers to reach the destination).

But if RIP is used it only counts the number of routers to reach the destination (the less the better) so it will choose path R1 -> R5 (hop count: 1) -> E is correct.QUESTION 6A. 1B. 3C. 4D. 2

RIPng or RIP next generation is implemented with IPv6

Answer 6Answer: B

QUESTION 7When a Cisco switch receives untagged frames on a 802.1Q trunk port, which VLAN ID is the traffic switched to by default?

A. Data VLAN IdB. Native VLAN IdC. Unused VLAN IdD. Management VLAN Id

Answer 7Answer: B

QUESTION 8Which statement describes a route that has been learned dynamically?

A. It is automatically updated and maintained by routing protocols. B. It is unaffected by changes in the topology of the network.C. It has an administrative distance of 1.D. It is identified by the prefix C in the routing table.

Answer 8Answer: A

QUESTION 9How many broadcast and collision domains exist in the topology?

5 broadcast domains and 11 collision domains10 broadcast domains and 5 collision domains16 broadcast domains and 11 collision domains5 broadcast domains and 10 collision domains

switchrouterrouterbridgeswitchhubCollision domainA collision domain is, as the name implies, a part of a network where packet collisions can occur. A collision occurs when two devices send a packet at the same time on the shared network segment. The packets collide and both devices must send the packets again, which reduces network efficiency. Collisions are often in a hub environment, because each port on a hub is in the same collision domain. By contrast, each port on a bridge, a switch or a router is in a separate collision domain.The following example illustrates collision domains.As you can see, we have 6 collision domains.TIP remember, each port on a hub is in the same collision domain. Each port on a bridge, a switch or router is in a seperate collision domain.Broadcast domainA broadcast domain is a domain in which a broadcast is forwarded. A broadcast domain contains all devices that can reach each other at the data link layer (OSI layer 2) by using broadcast. All ports on a hub or a switch are by default in the same broadcast domain. All ports on a router are in the different broadcast domains and routers don't forward broadcasts from one broadcast domain to another.The following example clarifies the concept.

In the picture above we have three broadcast domains, since all ports on a hub or a switch are in the same broadcast domain, and all ports on a router are in a different broadcast domain.

19Answer 9Answer: DCollision domainA collision domain is, as the name implies, a part of a network where packet collisions can occur. A collision occurs when two devices send a packet at the same time on the shared network segment. The packets collide and both devices must send the packets again, which reduces network efficiency. Collisions are often in a hub environment, because each port on a hub is in the same collision domain. By contrast, each port on a bridge, a switch or a router is in a separate collision domain.

Answer 9Answer: D

The following example illustrates collision domains.

In the picture above we have three broadcast domains, since all ports on a hub or a switch are in the same broadcast domain, and all ports on a router are in a different broadcast domain.As you can see, we have 6 collision domains.TIP remember, each port on a hub is in the same collision domain. Each port on a bridge, a switch or router is in a seperate collision domain.

Answer 9Answer: DBroadcast domainA broadcast domain is a domain in which a broadcast is forwarded. A broadcast domain contains all devices that can reach each other at the data link layer (OSI layer 2) by using broadcast. All ports on a hub or a switch are by default in the same broadcast domain. All ports on a router are in the different broadcast domains and routers don't forward broadcasts from one broadcast domain to another.Answer 9Answer: D

In the picture above we have three broadcast domains, since all ports on a hub or a switch are in the same broadcast domain, and all ports on a router are in a different broadcast domain.The following example clarifies the concept.

Answer 9 (cont)Answer: D

QUESTION 10

Which three statements are true about how router JAX will choose a path to the 10.1.3.0/24 network when different routing protocols are configured? (Choose three)QUESTION 10 (Cont.)By default, if RIPv2 is the routing protocol, only the path JAX-ORL will be installed into the routing table.The equal cost paths JAX-CHI-ORL and JAX- NY-ORL will be installed in the routing table if RIPv2 is the routing protocol.When EIGRP is the routing protocol, only the path JAX-ORL will be installed in the routing table by default.When EIGRP is the routing protocol, the equal cost paths JAX-CHI-ORL, and JAX-NY-ORL will be installed in the routing table by default.With EIGRP and OSPF both running on the network with their default configurations, the EIGRP paths will be installed in the routing table. The OSPF paths will be installed in the routing table, if EIGRP and OSPF are both running on the network with their default configurations.

Answer 10First we need to know the speed of these links:+ T1: 1.544 Mbps+ T3: 45 Mbps (each T3 line consists of 28 T1 lines)RIP chooses the path with minimum hop count to reach the destination so it will choose JAX-ORL path -> A is correct.EIGRP, by default, calculates metric via bandwidth & delay (metric = bandwidth + delay). Delay parameter can be ignored in this case so EIGRP will choose the path via metric. Both the path JAX-CHI-ORL and JAX- NY-ORL have the same metric (each includes two T3 lines) so EIGRP will use these paths -> D is correct.EIGRP has lower Administrative Distance than OSPF (EIGRP: 90 < OSPF: 110) which is better -> EIGRP will be preferred to OSPF -> E is correct.QUESTION 11What must be set correctly when configuring a serial interface so that higher-level protocols calculate the best route?

BandwidthDelayLoadReliability

Answer 11Higher-level protocols (OSPF, EIGRP) calculate the best route mainly based on bandwidth so it must be set correctly -> A is correct.

QUESTION 12Which destination addresses will be used by Host A to send data to Host C? (Choose two)

the IP address of Switch 1the MAC address of Switch 1the IP address of Host Cthe MAC address of Host Cthe IP address of the routers E0 interfacethe MAC address of the routers E0 interface

QUESTION 12 (Cont.)Answer 12

While transferring data through many different networks, the source and destination IP addresses are not changed. Only the source and destination MAC addresses are changed. So in this case Host A will use the IP address of Host C and the MAC address of E0 interface to send data. When the router receives this data, it replaces the source MAC address with it own E1 interfaces MAC address and replaces the destination MAC address with Host Cs MAC address before sending to Host C C and F are correct.

QUESTION 13Which routing protocols will support the following IP addressing scheme? (Choose three)Network 1 192.168.10.0 /26Network 2 192.168.10.64 /27Network 3 192.168.10.96 /27Network 4 192.168.10.128 /30Network 5 192.168.10.132 /30

RIP version 1RIP version 2IGRPEIGRPOSPF

Answer 13RIP v2, OSPF and EIGRP are classless routing protocol which support VLSM (Variable Length Subnet Masking ).

RIPv1 & IGRP can not be used in this network because they do not support Variable Length Subnet Masking (VLSM)

Notice that EIGRP is a Cisco-proprietary routing protocol so it can be used in Cisco routers only.Answer: B D E

QUESTION 14A medium-sized company has a Class C IP address. It has two Cisco routers and one non-Cisco router.All three routers are using RIP version 1.The company network is using the block of 198.133.219.0/24.The company has decided it would be a good idea to split the network into three smaller subnets and create the option of conserving addresses with VLSM.What is the best course of action if the company wants to have 40 hosts in each of the three subnets?Convert all the routers to EIGRP and use 198.133.219.32/27, 198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.Maintain the use of RIP version 1 and use 198.133.219.32/27, 198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.Convert all the routers to EIGRP and use 198.133.219.64/26, 198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.Convert all the routers to RIP version 2 and use 198.133.219.64/26, 198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.Convert all the routers to OSPF and use 198.133.219.16/28, 198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.Convert all the routers to static routes and use 198.133.219.16/28, 198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.

Answer 14When considering with RIP, OSPF handles its own error detection and correction functions.RIP uses auto summarization at classfull networks, and in OSPF, we use manual summarization, therefore, we dont have to give commands for auto summarization.While RIP using hop counts to calculate metric value, OSPF uses SPF (Shortest Path First) algorithm to select the best path. RIP uses lots of bandwidth as it sends periodic updates, but OSPF advertise only changes in a network.Rip takes 30-60 seconds to converge, but OSPF converges immediately even in larger network.RIP can be reached hop count of 15 routers, but OSPF can reach unlimited hop counts. Therefore, RIP can be used in smaller networks and OSPF can be used in larger networks.

36Answer 14RIP version 1 does not support VLSM so we have to convert into RIPv2, OSPF or EIGRP -> B is not correct.But EIGRP is a Cisco-proprietary routing protocol so it can not be used in a non-Cisco router -> A and C are not correct.To support 40 hosts per subnet we need a subnet mask of /26 or lower (which leaves 6 bits 0 and 26= 64 > 40 hosts). Therefore a subnet mask of /28 is not suitable in this case -> E & F are not correct.

Answer: D

37QUESTION 15Which statement is true, as relates to classful or classless routing?

RIPV1 and OSPF are classless routing protocols.Classful routing protocols send the subnet mask in routing updates.Automatic summarization at classful boundaries can cause problems on discontiguous networks.EIGRP and OSPF are classful routing protocols and summarize routes by default.

Classful networks use the 'classful' subnet mask according to the leading bits in the first block of the IP address:Class A begins with binary 0 (0-127.x.x.x)So and IP address 0.0.0.0 to 127.255.255.255 use subnet mask = 255.0.0.0Class B begins with binary 10 (128-191)So IPaddresses 128.0.0.0 to 192.255.255.255 use subnet mask = 255.255.0.0Class C begin with binary 110 (192-223)So IP addresses 192.0.0.0 to 255.255.255.0 use a subnet mask = 255.255.255.0Classless IP addressing means you can use any subnetmask you want, even assigning partial blocks. For example subnet 172.16.0.0 is a class B network.But you have two physical interfaces on your router that connect to switches with 5 VLANs. Classless routing allows me to break up this IP address into more useful segments.Switch 1 Switch 2VLAN1 172.16.1.0/24 VLAN10 172.16.10.0/24VLAN2 172.16.2.0/24 VLAN11 172.16.11.0/24VLAN3 172.16.3.0/24 VLAN12 172.16.12.0/24VLAN4 172.16.4.0/24 VLAN13 172.16.13.0/24VLAN5 172.16.5.0/24 VLAN14 172.16.14.0/24So I have made 10 useful subnets from a single network. Here's the real advantage:1.When my router is configured for classless routing it can advertise all 10 networks as one IP address172.16.0.0 255.255.240.0, or I can advertise each physical interface using172.16.0.0and172.16.8.0using ths subnet mask255.255.248.02.I still have spare room in the 172.16.0.0/16 for lots more subnets. If I want to create another group, do the binary math, I find the next available subnets are 172.16.24.0 255.255.248.0. If I use the#no auto-summarycommand on my routing protocol. I can place the new 172.16.x.x subnets anywhere in my network.

38Answer 15Answer: C

Classful routing protocols DO NOT send the subnet mask along with their updates.Classless routing protocols DO send the subnet mask along with their updates.

Difference Between RIP and OSPFRIP vs OSPF

RIP and OSPF are routing protocols used to advertise about routes in a network they are used as Interior Gateway Protocols (IGP), which are configured inside an autonomous system. Protocols are set of rules and regulations, and they are used with routers to establish connection inside a network in computer networking. Autonomous System is a group of routers that uses common protocol to communicate inside the group. Both RIP and OSPF are open standard industry protocols which can also be used with non-Cisco devices like Juniper. RIP and OSPF use Hello messages to find about routes and establish neighbors.RIPRIP is a distance vector protocol which advertises network updates periodically; in RIP, the advertisements are sent every 30 seconds, and it too triggers updates when a change in network happens. It uses hop counts to calculate the metric value, which determines the best path to reach a network. RIP supports maximum of 15 routers, and 16th hop is considered unreachable or unsharable. So, RIP can be used efficiently in small networks only. It uses several loop prevention techniques and those increase convergence time of a RIP implemented network , which can be recognized as its main weak point. There are three versions of RIP. RIP V1 and RIP V2 are supported in IPv4 environment, and RIPng or RIP next generation is implemented with IPv6. RIP V1 advertises classfull networks and do not carry subnet information, while RIP V2 carries subnet information in a network. To prevent incorrect routing information from being propagated throughout a network, RIP uses split-horizon, route poisoning and hold down. Its Advertisement Distance is 120. By AD or administrative distance we show how believable a route can be.OSPFOSPF is widely used as an Interior Gateway Protocol. After gathering information from available routers it constructs a topology map of a network. OSPF communicate using areas; they form neighbor relationship with routers in the same autonomous system first. Every area must be virtually or directly attached to a backbone area which is numbered as area 0. OSPF maintains routing table, neighbor table, and database table. To select best path, it uses Dijkstras Shortest Path First (SPF) algorithm. OSPF select a DR (Designated Router) and BDR (Border Designated Router) for a network, which can simply be defined as a captain and a vicecaptain of an army; they take orders from Captain or vice captain, but not from their colleagues. Every router is connected to these two main routers and communicates only with them, not with each other. When the DR goes down, BDR take its place and take the control of giving orders to other routers. This routing protocol use Advertisement Distance of 110 when advertising its networks.

39Answer 15Classful routing protocols DO NOT send the subnet mask along with their updates.Classless routing protocols DO send the subnet mask along with their updates.

Lets take a look at an example to emphasize this:

We have three routers and a bunch of networks. Take a close look at the networks that we have here:172.16.1.0 /24172.16.2.0 /24192.168.12.0 /24192.168.23.0 /24

Difference Between RIP and OSPFRIP vs OSPF

RIP and OSPF are routing protocols used to advertise about routes in a network they are used as Interior Gateway Protocols (IGP), which are configured inside an autonomous system. Protocols are set of rules and regulations, and they are used with routers to establish connection inside a network in computer networking. Autonomous System is a group of routers that uses common protocol to communicate inside the group. Both RIP and OSPF are open standard industry protocols which can also be used with non-Cisco devices like Juniper. RIP and OSPF use Hello messages to find about routes and establish neighbors.RIPRIP is a distance vector protocol which advertises network updates periodically; in RIP, the advertisements are sent every 30 seconds, and it too triggers updates when a change in network happens. It uses hop counts to calculate the metric value, which determines the best path to reach a network. RIP supports maximum of 15 routers, and 16th hop is considered unreachable or unsharable. So, RIP can be used efficiently in small networks only. It uses several loop prevention techniques and those increase convergence time of a RIP implemented network , which can be recognized as its main weak point. There are three versions of RIP. RIP V1 and RIP V2 are supported in IPv4 environment, and RIPng or RIP next generation is implemented with IPv6. RIP V1 advertises classfull networks and do not carry subnet information, while RIP V2 carries subnet information in a network. To prevent incorrect routing information from being propagated throughout a network, RIP uses split-horizon, route poisoning and hold down. Its Advertisement Distance is 120. By AD or administrative distance we show how believable a route can be.OSPFOSPF is widely used as an Interior Gateway Protocol. After gathering information from available routers it constructs a topology map of a network. OSPF communicate using areas; they form neighbor relationship with routers in the same autonomous system first. Every area must be virtually or directly attached to a backbone area which is numbered as area 0. OSPF maintains routing table, neighbor table, and database table. To select best path, it uses Dijkstras Shortest Path First (SPF) algorithm. OSPF select a DR (Designated Router) and BDR (Border Designated Router) for a network, which can simply be defined as a captain and a vicecaptain of an army; they take orders from Captain or vice captain, but not from their colleagues. Every router is connected to these two main routers and communicates only with them, not with each other. When the DR goes down, BDR take its place and take the control of giving orders to other routers. This routing protocol use Advertisement Distance of 110 when advertising its networks.

40Answer 15Remember the class A,B and C ranges?172.16.1.0 and 172.16.2.0 fall within the class B range.192.168.12.0 and 192.168.23.0 fall within the class C range.What subnet mask do class B and class C networks have by default?Class B: 255.255.0.0Class C: 255.255.255.0A classful routing protocol will not send the subnet mask along with the routing update so this is what will happen:

Router Spade and router Clubs dont send the subnet mask along with the routing update so it will advertise the classful network which is 172.16.0.0 in this case. So what happens with router Hearts? It thinks it can reach the 172.16.0.0 network by sending packets either left or right and if the metric is equal it will try to load-balance. Obviously this is going to cause problems.Classless routing protocols advertise the subnet mask along with their updates:As you can see router Spade is now advertising its 172.16.1.0 subnet with a subnet mask. Router Clubs is advertising its 172.16.2.0 subnet with a subnet mask as well.

Difference Between RIP and OSPFRIP vs OSPF

RIP and OSPF are routing protocols used to advertise about routes in a network they are used as Interior Gateway Protocols (IGP), which are configured inside an autonomous system. Protocols are set of rules and regulations, and they are used with routers to establish connection inside a network in computer networking. Autonomous System is a group of routers that uses common protocol to communicate inside the group. Both RIP and OSPF are open standard industry protocols which can also be used with non-Cisco devices like Juniper. RIP and OSPF use Hello messages to find about routes and establish neighbors.RIPRIP is a distance vector protocol which advertises network updates periodically; in RIP, the advertisements are sent every 30 seconds, and it too triggers updates when a change in network happens. It uses hop counts to calculate the metric value, which determines the best path to reach a network. RIP supports maximum of 15 routers, and 16th hop is considered unreachable or unsharable. So, RIP can be used efficiently in small networks only. It uses several loop prevention techniques and those increase convergence time of a RIP implemented network , which can be recognized as its main weak point. There are three versions of RIP. RIP V1 and RIP V2 are supported in IPv4 environment, and RIPng or RIP next generation is implemented with IPv6. RIP V1 advertises classfull networks and do not carry subnet information, while RIP V2 carries subnet information in a network. To prevent incorrect routing information from being propagated throughout a network, RIP uses split-horizon, route poisoning and hold down. Its Advertisement Distance is 120. By AD or administrative distance we show how believable a route can be.OSPFOSPF is widely used as an Interior Gateway Protocol. After gathering information from available routers it constructs a topology map of a network. OSPF communicate using areas; they form neighbor relationship with routers in the same autonomous system first. Every area must be virtually or directly attached to a backbone area which is numbered as area 0. OSPF maintains routing table, neighbor table, and database table. To select best path, it uses Dijkstras Shortest Path First (SPF) algorithm. OSPF select a DR (Designated Router) and BDR (Border Designated Router) for a network, which can simply be defined as a captain and a vicecaptain of an army; they take orders from Captain or vice captain, but not from their colleagues. Every router is connected to these two main routers and communicates only with them, not with each other. When the DR goes down, BDR take its place and take the control of giving orders to other routers. This routing protocol use Advertisement Distance of 110 when advertising its networks.

41QUESTION 16Which two are advantages of static routing when compared to dynamic routing? (choose two)Security increases because only the network administrator may change the routing tables.Configuration complexity decreases as network size increases.Routing updates are automatically sent to neighbors.Route summarization is computed automatically by the router.Routing traffic load is reduced when used in stub network links.An efficient algorithm is used to build routing tables using automatic updates.Routing tables adapt automatically to topology changes.

42Answer 16Answer: A E 43QUESTION 17Which protocol gives a full route table update every 30 seconds

IEGRPRIPboth of abovenone of above

44Answer 17Answer: B45QUESTION 18Which statement is true regarding classless routing protocolThe use of discontiguous networks is not allowedUse of variable length subnet masks is permittedRIPv1 is a classless routing protocolIGRP supports classes routing within the same autonomous system46Answer 18Answer: B47QUESTION 19Which is not a valid type of routing?Static routingDefault routingDynamic routingCustom routing

48Answer 19Answer: D QUESTION 20Default administrative distance

EIGRP 0 and Static route 0EIGRP 1 and Static route 90EIGRP 110 and Static route 100EIGRP 90 and Static route 1

Answer 20Answer: D