Configuring And troubleshooting routers

Question 1

Data store on an IP host used to determine the interface over which to forward a packet

Answer 1

Routing table

Question 2

Entry in the routing table representing a subnet in which the router has an active interface

Answer 2

Directly connected routes

Question 3

Entry in the routing table to represent the forwarding path that will be used if no other entries are matched

Answer 3

Default route

Question 4

One link in the path from a host to a router or from router to router. Each time a packet passes through a router it’s hip count or TTL is decreased by one.

Answer 4

Hop

Question 5

Counter field in the IP header recording the number of hops a packet can make before being dropped.

Answer 5

Time to Live (TTL)

Question 6

Mechanism for splitting a layer 3 data gram between multiple frames to fit the maximum transmission unit of the underlying data link network.

Answer 6

Fragmentation

Question 7

Entry in the routing table that has been learned from another router via a dynamic routing protocol

Answer 7

Dynamic routing

Question 8

Algorithm used by routing protocols that select a forwarding path based on the next hop router with the lowest hop count to the destination network

Answer 8

Distance vector

Question 9

Algorithm used by routing protocols that build a complete network topology to use to select optimum forwarding paths

Answer 9

Link state

Question 10

Process whereby routers agree on routes through the network to establish the same network topology in their routing tables (steady state). The time taken to reach steady state is a measure of a routing protocols convergence performance.

Answer 10

Convergence

Question 11

Group of network prefixes under the administrative control of a single organization used to establish routing boundaries

Answer 11

Autonomous system (AS)

Question 12

Dynamic routing protocol used to exchange path forwarding information between routers in the same autonomous system

Answer 12

Interior gateway protocol (IGP)

Question 13

Dynamic routing pro tool used to exchange information about network paths in separate autonomous systems

Answer 13

Exterior gateway protocol (EGP)

Question 14

Distance vector based routing protocol that uses a hop count to determine the least cost path to a destination network

Answer 14

Routing information protocol (RIP)

Question 15

Advanced distance vector dynamic routing protocol using bandwidth and delay methods ice to establish optimum forwarding paths

Answer 15

Enhanced IGRP (EIGRP)

Question 16

Dynamic routing protocol that uses a link state algorithm and a hierarchical toplogy

Answer 16

Open shortest path first (OSPF)

Question 17

Lath vector exterior gateway routing protocol used principally by ISPs to establish routing between autonomous systems.

Answer 17

Border gateway protocol (BGP)

Question 18

Metric determining the trustworthiness of routes derived from different routing protocols

Answer 18

Administrative distance (AD)

Question 19

Using network prefixes to aggregate routes to multiple network blocks (super netting). This replaced the old method of assigning class based up addresses based on the network size

Answer 19

Classless inter domain routing (CIDR)

Question 20

Using network prefixes of different lengths with an IP network to create subnets of different sizes

Answer 20

Variable length subnet masking (VLSM)

Question 21

Configuring a routers physical interface with multiple virtual interfaces connected to separate virtual LAN (VLAN) IDs over a trunk

Answer 21

Subinterfaces

Question 22

Switch appliance capable of IP routing between virtual LAN (VLAN) subnets using hardware optimized path selection and forwarding

Answer 22

Layer 3 capable switch

Question 23

Cross platform command tools used display and manage the routing table on a Windows or Linux host

Answer 23

Route

Question 24

Diagnostic utilities that trace the route taken by a packet as it hops to the destination host on a remote network. Tracert is the windows implementation while trace route runs on Linux

Answer 24

Traceroute

Question 25

Troubleshooting issue where a routing table does not contain a required entry due either to manual misconfiguration or failure if a dynamic routing protocol update.

Answer 25

Missing route

Question 26

Troubleshooting issue where a packet is forwarded between routers in a loop until it’s TTL expires.

Answer 26

Routing loop

Question 27

Topology where the return path is different to the forward path

Answer 27

Asymmetrical routing

Question 28

Assessment of allowable signal loss over a fiber optic link

Answer 28

Optical link budget