Someone Please Help Me Understand
faisal at snappytelecom.net
Mon Apr 4 00:26:37 UTC 2016
With this type of connectivity you have to pay attention to Traffic Engineering...
And when I say, traffic engineering, I mean both ways.. how you are sending traffic to them
along with how they are sending traffic to you... (sometimes a bit more challenging to do).
I will give you two specific example, just to illustrate the point...
We are located in the east coast, we have ip transit to Cogent network, via one intermediary ASN.
We also have IP Transit with GTT and Hibernia networks.
We also have direct peering on multiple Peering Fabrics.
We have our outbound traffic engineered to prefer direct routes.. e.g. when sending traffic to Cogent, we send
it out via the intermediary ASN to Cogent.
However when traffic is coming back from Cogent.... they see our prefixes via intermediary ASN as well as Hibernia Networks,
since Hibernia networks is a lower ASN, they prefer that route....
So, one can say, no big deal, except, Hibernia Networks connects to Cogent on the West Coast !... so our return traffic is going
from the east coast to west coast and them back to east coast....
So one can easily say... Houston we have a problem !...
We are peered with some networks at Telx TIE, via one of our (intermediary) ASN...So while we can send traffic over to that network via our ASN, however that networks sees our prefixes via our (intermediary) ASN as Hibernia as well.... Hibernia being a lower ASN, they send traffic back to us via them...
In both cases we use communities to take corrective action....
Moral of the story is..... just because you have multiple peers, and peer with folks on the Peering Fabric, the default configuration of BGP will not AUTOMAGICALY optimize the paths in your favor....
And thus the condition you describe will be the result...
Snappy Internet & Telecom
7266 SW 48 Street
Miami, FL 33155
Tel: 305 663 5518 x 232
Help-desk: (305)663-5518 Option 2 or Email: Support at Snappytelecom.net
----- Original Message -----
> From: "Eric Rogers" <ecrogers at precisionds.com>
> To: "nanog list" <nanog at nanog.org>
> Sent: Saturday, April 2, 2016 1:54:40 PM
> Subject: Someone Please Help Me Understand
> Ok, I'm trying to learn, so bear with me.
> We are an ISP in Indianapolis that has full routes from 3 different
> providers HE.Net in Columbus OH being one. We also are peered with 2
> peering exchanges, including EquinixIX in Chicago. The problem is
> Instagram and Facebook (same company, I know) for our customers seems
> very slow.
> This is where I need a way to troubleshoot/understand more. I did a
> traceroute to the IP that is serving the pictures, and it resolves to
> the FBCDN servers in Dallas, and is showing packet loss and pings once
> it hits Dallas, and are in the 1xxs of ms.
> Tracing route to instagram-p3-shv-01-dfw1.fbcdn.net [18.104.22.168]
> over a maximum of 30 hops:
> 1 4 ms 3 ms 4 ms 10.7.0.1
> 2 20 ms 43 ms 42 ms inmtvlobs-rtr-01.dynamic.pdsconnect.me
> 3 25 ms 47 ms 29 ms
> inmtvlmwt-rtr-01.infrastructure.pdsconnect.me [22.214.171.124]
> 4 46 ms 32 ms 58 ms
> inindyhen-core1.infrastructure.pdsconnect.me [126.96.36.199]
> 5 36 ms 53 ms 51 ms ge2-4.core1.cmh1.he.net [188.8.131.52]
> 6 47 ms 41 ms 75 ms 10ge1-2.core1.chi1.he.net
> 7 57 ms 57 ms 53 ms 100ge14-1.core2.chi1.he.net
> 8 57 ms 73 ms 84 ms 100ge12-1.core1.mci3.he.net
> 9 75 ms 73 ms 102 ms 10ge15-6.core1.dal1.he.net
> 10 93 ms 103 ms 92 ms eqix-da1.facebook.com [184.108.40.206]
> 11 102 ms 101 ms * psw01c.dfw1.tfbnw.net [220.127.116.11]
> 12 92 ms 97 ms 105 ms msw1aq.01.dfw1.tfbnw.net [18.104.22.168]
> 13 110 ms * 98 ms instagram-p3-shv-01-dfw1.fbcdn.net
> Since I am peered with the route servers in EquinixIX Chicago, shouldn't
> the data be coming from there, or at least hit their routers? In my
> trace, it shows HE to Chicago, then to Dallas. How does FB decide what
> IP the content gets displayed from, and is there anything I can do as a
> provider? If it is DNS, I can obviously clear the cache to see if it
> gets new IPs. If I'm not getting FB peering IPs in Chicago, do I need
> to peer directly? Should I get FaceBook involved?
> Eric Rogers
> PDS Connect
> (317) 831-3000 x200
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