Characteristics of Routing Protocols

Question 1

Which of the following features prevents a route learned on one interface from being advertised back out of that interface?

Answer 1

Split Horizon

Question 2

Identify two distance-vector routing protocols

Answer 2

EIGRP and RIP

Question 3

Which type of network communication flow that is best described as “one-to-nearest.”

Answer 3

Anycast

Question 4

An NBMA network has what kind of design issues in respect to routing protocols?

Answer 4

Split Horizon, Designated router issues

Question 5

Define TCP MSS

Answer 5

The total data in a TCP segment, not including any headers

Question 6

A networking segment has a bandwidth of 10 Mbps, and packets experience an end-to-end latency of 100 ms. What is the bandwidth-delay product of the network segment?

Answer 6

1,000,000 bits / 1Mb

Question 7

When migrating from a PVST+ to Rapid-PVST+, which two PVST+ features an be disabled, because similar features are built into Rapid-PVST+?

Answer 7

Uplink Fast, Backbone Fast

Question 8

Cisco EVN uses what type of trunk to carry traffic for all virtual networks between two physical routers?

Answer 8

VNET

Question 9

How would you reduce the number of entries in a router’s routing table?

Answer 9

Route summarization

Question 10

The design calls for the use of a distance- vector routing protocol. Identify the two approaches that a distance-vector routing protocol can use to prevent loops. (2)

Answer 10

Split Horizon. Poison Reverse.

Question 11

The design calls for the use of a link-state routing protocol. (2)

Answer 11

Use OSPF. Use IS-IS.

Question 12

The design calls for IPv6 traffic to travel from a source IPv6 address to the nearest device of multiple devices assigned the same destination IPv6 address.

Answer 12

Use anycast.

Question 13

The design calls for the use of an NBMA network. Identify design issues that might be encountered when using EIGRP or OSPF. (2)

Answer 13

Issue with EIGRP: Split Horizon. Issue with OSPF: Designated router.

Question 14

The design calls for the use of Hot Standby Router Protocol (HSRP). Identify the condition that can be created when return traffic flows through a standby HSRP router.

Answer 14

Asymmetric routing (or unicast flooding).

Question 15

The design needs to mitigate a global synchronization condition (where all TCP flows simultaneously enter TCP slow start).

Answer 15

Use WRED (Weighted random early detection).

Question 16

The design requires a network to be migrated to a different routing protocol. (2)

Answer 16

Configure both routing protocols, and use Administrative Distance (AD) to control which routing protocol is being used.
Use route redistribution as you migrate individual sections of the network.

Question 17

The design requires that you virtualize multiple routers inside of physical routers and carry traffic for the virtual networks between those physical routers.

Answer 17

Use Cisco Easy Virtual Networking (EVN) (VRFs).

Question 18

The plan requires that Split Horizon be disabled for the hub router in a hub-and- spoke topology. Describe the purpose of Split Horizon.

Answer 18

Split Horizon is a feature that prevents a route learned on one interface from being advertised back out of that same interface.

Question 19

The plan requires the use of EIGRP as the routing protocol. Provide a brief description of EIGRP.

Answer 19

Enhanced Interior Gateway Routing Protocol (EIGRP) is classified as an advanced distance- vector routing protocol. It was Cisco- proprietary until early 2013, but is now open to other vendors. EIGRP uses the Diffusing Update Algorithm (DUAL) to make its path selection decisions.

Question 20

The plan calls for the use of both IPv4 and IPv6. What network traffic types do IPv4 and IPv6 have in common, and what traffic types are different?

Answer 20

Both IPv4 and IPv6 use unicasts and multicasts. However, IPv4 can use broadcasts, while IPv6 cannot. Also, IPv6 supports anycasts, while IPv4 does not.

Question 21

The plan calls for the use of Hot Standby Router Protocol (HSRP). What can you do to prevent an asymmetric routing issue, where traffic is forwarded from a subnet using the active HSRP router, and some of the return traffic returns using the standby HSRP router (because of load balancing)?

Answer 21

Ideally, you should not span a VLAN across more than one access layer switch. However, if you must span a VLAN across multiple access layer switches, you can adjust the HSRP router’s ARP timer to be equal to or less than the CAM aging time.

Question 22

The design calls for the transmission of interactive voice and video over a network. What Layer 4 protocols are typically used to transmit voice and data media? (2)

Answer 22

The Real-time Transport Protocol (RTP) is a Layer 4 protocol that carries voice and video media. RTP is encapsulated inside of User Datagram Protocol (UDP), which is another Layer 4 protocol.

Question 23

The plan requires that a network migrate from IPv4 to IPv6. Identify three strategies of a successful IPv6 migration. (3)

Answer 23

Check existing equipment for IPv6 compatibility.

Run IPv4 and IPv6 concurrently. Check the ISP’s support for IPv6.

Question 24

The plan calls for the use of Virtual Routing and Forwarding (VRF). Identify two approaches to configuring VRF. (2)

Answer 24

A traditional way to configure VRF on Cisco routers is an approach called VRF-Lite.
A newer approach to virtualized network configuration, called Cisco Easy Virtual Network (EVN), dramatically simplifies the relatively complex configuration required by VRF-Lite.