Someone Please Help Me Understand

Mike Hammett nanog at
Sat Apr 2 18:01:04 UTC 2016

Are you using locally resolving DNS servers? I don't know how FB determines where your content comes from, but some CDNs test the performance to your resolving DNS server. 

Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

----- Original Message -----

From: "Eric Rogers" <ecrogers at> 
To: nanog at 
Sent: Saturday, April 2, 2016 12:54:40 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 [] 

over a maximum of 30 hops: 

1 4 ms 3 ms 4 ms 

2 20 ms 43 ms 42 ms 

3 25 ms 47 ms 29 ms [] 

4 46 ms 32 ms 58 ms [] 

5 36 ms 53 ms 51 ms [] 

6 47 ms 41 ms 75 ms 

7 57 ms 57 ms 53 ms 

8 57 ms 73 ms 84 ms 

9 75 ms 73 ms 102 ms 

10 93 ms 103 ms 92 ms [] 

11 102 ms 101 ms * [] 

12 92 ms 97 ms 105 ms [] 

13 110 ms * 98 ms 

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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