BGP

techED

Question:
The BGP btw 2 ISP fails, what effect, if any, will the failure have on both ISP's client?

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Comments

dmaftei

It depends on topology, the effects could range from "no client will be affected" to "all clients in one ISP will be affected".

hectorjhrdz

if you lose BGP, you lose routing info btw 2 ISPs so the client won't exit to the internet...

i think so, i'm work on an ISP and when we lose the "peering" with the another ISP, our traffic stops to flow on that link..

cherrs

keenon

interesting.... not really a ccna topic

good to see others starting to look ahead

dmaftei

hectorjhrdz wrote:

if you lose BGP, you lose routing info btw 2 ISPs so the client won't exit to the internet...

The BGP terminology is Autonomous System (AS), not ISP.

If your ISP, say AS-100, has only one uplink towards the internet through AS-200, and that link goes down, then everybody in AS-100 loses internet connection.

If AS-100 has two uplinks, through AS-200 and AS-300, and the link between AS-100 and AS-200 goes down, then internet traffic from AS-100 will go through AS-300. At most there will be some temporary disruptions until the routing tables are updated.

That's what I meant by "it depends on topology".

hectorjhrdz

it's correct...

If AS-100 has two uplinks, through AS-200 and AS-300, and the link between AS-100 and AS-200 goes down, then internet traffic from AS-100 will go through AS-300. At most there will be some temporary disruptions until the routing tables are updated.

i have a question.. Suppose we have the same scenario that you mentioned above , Do you need to set BGP load balancing in both links to automatic perform that action or simply BGP features are enough to do that?

dmaftei

Sorry but that's a level of detail that I don't remember anymore, you'll have to wait for somebody else to answer this question.

keenon

hectorjhrdz wrote:

it's correct...

If AS-100 has two uplinks, through AS-200 and AS-300, and the link between AS-100 and AS-200 goes down, then internet traffic from AS-100 will go through AS-300. At most there will be some temporary disruptions until the routing tables are updated.

i have a question.. Suppose we have the same scenario that you mentioned above , Do you need to set BGP load balancing in both links to automatic perform that action or simply BGP features are enough to do that?

Bgp doesn't load balance. BGP picks the best path to a destination per advertising router(eBgp speaker/AS) what it sounds like will involve some attribute manipulation external from your (ebgp speaker/AS)

as i said not really a ccna topic

hectorjhrdz

changos!!!
as you said not a CCNA topic thnks for the illustration whatever

cheers