Answer Happy

ASI AS2 RL R2 16 Source AS3 R9 AS4 'R13 R12 RIC destination Assume that we have a network topology which contains 4 Autonomous Systems, AS1, AS2, AS3, and AS4. Assume that all business relations between ASes are peer-to-peer. a-) (16 points] For given topology, show all BGP path advertisements for destination X in each BGP speaking routers. Only show AS-PATH and NEXT-HOP attributes. You can use R1, R2, R3 etc. as IP address of the router. Note: You don't need to redraw the topology. Verbal answer is fine. E.g. From R1 - R2 => AS-PATH = {ASX, ASY, ASZ} Next-hop = {Rx} Write all BGP path advertisement like this. HINT: BGP protocol is destination based, not source based.

b-) [5 points] Explain what can be the reason for choosing the "AS1-AS2-AS3" path instead of the "AS1-AS4-AS3" path. C-) [6 points] Show which links use eBGP and which links use IBGP. Note 1: You can assign labels to each links and show your results. E.g. R1 - R2 => label1, uses IBGP or eBGP. Note: You can redraw the topology figure here. Note 2: If you prefer, you can use --- for iBGP and --- for eBGP. Choose the one which is easier for you (Note 1 or Note 2)