Question

19) Consider the network shown below. Suppose AS3 and AS2 are running OSPF for their intra-AS (10pts) routing protocol. Suppose AS1 and AS4 are running RIP for their intra-AS routing protocol. Suppose eBGP and iBGP are used for the inter-AS routing protocol. Initially suppose there is no physical link between AS2 and AS4. a) Which routers in AS1 run eBGP? b) Which routers in AS1 run iBGP? c) Which routers in AS1 run OSPF? 4b 4c 4a 30 AS4 2c За 3b 2a 1c 2b 1b AS3 1a AS2 1d 12 AS1 a Select One b Select One n Select One

The answers to choose from are

-1a,1b

-none

-1b,1c

-all

-1a,1b,1c

-1b,1c

-1b,1c,1d

-1a,1b,1c,1d

Answer 1

AS stands for Autonomous System number and is assigned by IANA(Internet Assigned Number Authority) to different network administrator. The protocol used to communicate between different AS is eBGP(external Border Gateway Protocol). RIP and OSPF are also routing protocols but used among same AS number.

Answer to a)

In AS1 1b and 1c will run eBGP as they are the border router and is used to communicate between different AS.

Answer to b)

In AS1 1a,1b,1c and 1d will run iBGP . As iBGP is used to communicate between same AS.Routes that belongs to different AS is advertised using iBGP in same AS

Answer to c)

In AS1 1a,1b,1c and 1d will run OSPF . As OSPF is used to communicate between same AS.Internal network is advertised using OSPF within same AS.