Re: /24 multihoming issue
I got an answer for my question. 7018/ATT does ACCEPT /24 routes from 701/mci. e.g 24.143.13.0/24 on route-server.ip.att.net has AS-PATH (7018 701 13368). Is 7018 preferring 19094 over 701 regardless of AS-PATH length? Or, 7018 will not take prefixes from other peers if a particular prefix is coming from 19094 regardless of AS-PATH? ** 7018 is just an example. There a quite a few ISP with the same behavior. Well .. I'm still in the maze. --- Kyaw Khine <joekhine@yahoo.com> wrote:
Says .. I pick 7018/AT&T. 7018 is accepting 701/mci customer routes. But is 7018 accepting 701/mci customer /24 routes ??? 7018 is definitely accepting 19094/telcove /24 routes because I see 64.9.17.0/24 on ATT route-server (route-server.ip.att.net)
So, why is 7018 receiving/accepting /24 from some peers (19094) but not from others (701)???
That .. I can't figure out.
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On Oct 20, 2005, at 3:51 AM, Randy Bush wrote:
Is 7018 preferring 19094 over 701 regardless of AS-PATH length?
the convention is that, if 19094 is a customer of 7018, then it will always prefer it.
And this is a good reason not to cross "tiers" of your transit providers. Either have both "transit free" or both should have transit.
Is 7018 preferring 19094 over 701 regardless of AS-PATH length? the convention is that, if 19094 is a customer of 7018, then it will always prefer it.
and it was confirmed that this is the case for the prefix in question
And this is a good reason not to cross "tiers" of your transit providers. Either have both "transit free" or both should have transit.
why? when it get up to tier-1s it will be the same, the one(s) who heard it from customers will prefer the customers. and tier-Ns should be preferring customer routes as well; see discussion here between vaf, asp, and me in about '96. randy
On Oct 20, 2005, at 2:07 PM, Randy Bush wrote:
Is 7018 preferring 19094 over 701 regardless of AS-PATH length?
the convention is that, if 19094 is a customer of 7018, then it will always prefer it.
and it was confirmed that this is the case for the prefix in question
And this is a good reason not to cross "tiers" of your transit providers. Either have both "transit free" or both should have transit.
why? when it get up to tier-1s it will be the same, the one(s) who heard it from customers will prefer the customers.
and tier-Ns should be preferring customer routes as well; see discussion here between vaf, asp, and me in about '96.
slipping back into the tier terminology which i was trying to avoid... it's only a problem if you want to do inbound traffic engineering. If the tier 2 is well connected to tier 1s (for example Internap), it's typically going to get more inbound traffic than the tier 1 connection because the tier 2 is preferred as a customer in a bunch of tier 1s.
participants (3)
-
John Payne -
Kyaw Khine -
Randy Bush