Routing Protocols

Question 1

Routing Protocol

Answer 1

Routers talk to one another about the state of the network and of nearby devices.

The protocols they use for to talk to each other are called routing protocols.

Question 2

OSPF

Answer 2

Open Shortest Path First

A Link-State Routing Protocol that is used to find the best path between the source and the destination router using its own Shortest Path First.

This is an Interior Gateway Protocol (IGP)

Question 3

RIP

Answer 3

Routing Information Protocol

A Distance-Vector protocol that uses hop count to determine the best path between the source and destination.

This is an Interior Gateway Protocol (IGP)

Question 4

Distance-vector type

Answer 4

Update Mechanism: Exchange entire routing tables with neighbors.

Topology Information: Limited; based on hop count and overall cost.

Update Triggers: Periodic timer or topology changes trigger updates.

Convergence Time: Slower; “count-to-infinity” problem.

Scalability: May suffer in larger networks due to table exchanges.

Question 5

Link-state type

Answer 5

Update Mechanism: Share information about directly connected links.

Topology Information: Detailed and up-to-date network map.

Update Triggers: Changes in link states trigger updates.

Convergence Time: Faster; routers quickly react to changes.

Scalability: Generally more scalable, targeted updates.

Question 6

RIPv1 Features

Answer 6

Classful Routing

Uses Broadcast

No Built-in Authentication

No Route Tagging

Question 7

RIPv2 Features

Answer 7

Classless Routing

Uses Broadcast & Multicast

Built-in Authentication Support

Route Tagging

Question 8

IGP

Answer 8

Interior Gateway Protocol

Definition: IGP is a type of routing protocol used for exchanging routing information within a single autonomous system (AS).

Scope: Operates within a single autonomous system, which is a collection of routers and networks under a common administration.

Examples: RIP (Routing Information Protocol), OSPF (Open Shortest Path First), and EIGRP (Enhanced Interior Gateway Routing Protocol) are examples of IGPs.

Question 9

EGP

Answer 9

Exterior Gateway Protocol

Definition: EGP is a type of routing protocol used for exchanging routing information between different autonomous systems.

Scope: Operates between autonomous systems, facilitating routing between networks that belong to different organizations or entities.

Example: BGP (Border Gateway Protocol) is the most commonly used EGP on the internet.

Question 10

BGP

Answer 10

Border Gateway Protocol

An Exterior Gateway Protocol (EGP) used to exchange routing and reachability information between different Autonomous Systems (ASes) on the Internet.

BGP is commonly used for routing between different ISPs and large enterprise networks.

Question 11

AS

Answer 11

Autonomous System

A collection of IP networks and routers under the control of a single organization or entity that presents a common routing policy to the internet.

Question 12

IGRP

Answer 12

Interior Gateway Routing Protocol

Limited to Cisco devices and only supports IPv4.

Does not support CIDR and VLSM

Its evolution, EIGRP, is used more often.

Question 13

EIGRP

Answer 13

Enhanced Interior Gateway Routing Protocol

An industry standard protocol that supports IPv6.

Supports CIDR and VLSM

Commonly used in modern networks.

Question 14

IS-IS

Answer 14

Intermediate System to Intermediate System

A link-state protocol commonly used in large scale networks by ISPs and telecom companies.

Widespread used in IPv4 and IPv6 networks.

It is capable of carrying routing information for multiple network layer protocols.