AS 65432 Now suppose that AS6 announces the lower half of its address space (12.
ID: 3912282 • Letter: A
Question
AS 65432 Now suppose that AS6 announces the lower half of its address space (12.2.0.0/17) from the XE link, and the upper half from the Y-C link. Let a's IP address be 12.2.33.65 and b's IP address be 12.2.192.66. What is the path from a to b? From a to c? From a to d? From c to a? From d to a? AS 2 a to b: a->>>x->y->b (as all the networks n ming OSPF) a to c: a-2-xycY will be the connecting BGP router for c, as its Y-C link who has announced uRBRCr half) a to d: a>x-*hofk->d (following OSPF QSEE inside network and IBGP between the ASÍ c to a: c->e->x-z->a (x-e link has announced lower half) c to d: c->b->a->n??>s->d or c->b->a->n->m->l->s->d (c will reach its border router using OSPF which is A, in AS2 there are two parallel paths to reach border router L which will connect to unnamed network via K & M) AS 3 What is undesirable about the flow of traffic in the previous question? Suggest a way to fix it. AS 6 What is undersirable about the flow of traffic in the above question (answer in blue)? Suggest a way to fix it. --Diagram for reference to left- AS1, AS2, and AS3 are ISPs, peering with each other at the links between routers J-K, N-A, and D-G AS6 is a customer of AS1 and AS3. Two more customer networks are shown. .All routers are shown. All links between routers are shown. All networks are running OSPF as their IGP, aink costs are equal. The prefix for AS6 is 12.2.0.0/16. The prefix forA65432 is 135.207.16.0/20. The prefix .All providers are running I-BGP for the naeless customer containing router S and host d is 192.20.225.0/24 .AS1, AS2, and AS3 number their routers out of 1.0.0.0/8, 2.0.0.0/8, and 3.0.0.0/8, respectively 0 not make any unnecessary assumption. If you have to make any assumptions they have to be easonable and state them very clearlyExplanation / Answer
Between AS6 and AS1 there are two bridges tha connect both the ASs together. Also both X-E and Y-C are announcing the address space this might create loops in the AS-path resulting in indefinite length paths or else multiple possible paths may increase network traffic. To fix this, choose any one of the above two (XE/YC) to announce the address space to avoid any kind of ambiguity in the network.