Refer to the exhibit.
In this BGP design, what is the next hop for 10.1.1.0/24 on R8 and R7?
A. The next hop for 10.1.1.0/24 on R7 is R8 and the next hop for R8 is R7.
B. The next hop for 10.1.1.0/24 on R7 is R5 and the next hop for R8 is R6.
C. The next hop for 10.1.1.0/24 on R7 is R6 and the next hop for R8 is R5.
D. The next hop for 10.1.1.0/24 on R7 is R3 and the next hop for R8 is R4.
Answer: A
Explanation:
Hello! The answer A seems to be wrong, woundn’t it be a looping case?
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No loops. Look at it this way. 3 and 4 will advertise the routes to 5 and 6 through ibgp. This means 3 and 4 remain next hops out of the AS.
Both 3 and 4 are RR clients of 5 and 6 respectively. Because 3 and 4 are clients; 5 and 6 will send the next hop route of 3 and 4 to everyone they have a session with. Because 5 has no session with 7, (nor 6 with 8) 7 will get the update from 6 and look for R4 as an exit. 8 will get an update from 5 and look to exit the ASN through R3.
This is bgp next hop. The only way for 8 to reach 3 is to go through the physical connectivity and igp making it go through r7 to get out of the ASN
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I guess the reason for this is that the question is just asking what is the next hop on to the /24 subnet on the router not asking what is the BGP next hop address is – which is the IGP next hop to reach the BGP next hop address which in mind the answer would have been answer C.
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what a silly question, intentionally to mislead without clear phrase…
good catch, guys!!
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Everything discussed above is true, but still, looking at the routing table on 7 or 8, you would see a BGP route (B) towards AS 500 with a next-hop which is NOT the IGP next-hop, but the BGP one. The router will eventually reach the IGP next-hop after one or more recursive lookups in the routing table, but the route is a BGP one and DOES have a BGP next-hop.
Now, unfortunately, in absence of the BGP next-hop propagation feature on RR (which is not mentioned as being in use), the EBGP next-hop is being carried into IBGP which, in our case, would be R1 and R2, but there is no valid answer for this.
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Agree with Matt Allen.
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And, part of that new 493Q 352-001 dumps:
https://drive.google.com/open?id=0B-ob6L_QjGLpflFYOFdyS1ctQVc2X1cwT0d2R2dyZzBsb2hPaGw5V2Y5akx5QmxxYUdOOUU
Best Regards!
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