AT&T/L3 interconnect?

While jumping on the wagon of poking at a particular 175.x.x.x address, I noticed something in my trace:

10 5 ms 5 ms 5 ms []
11 73 ms 72 ms 73 ms []
12 74 ms 74 ms 75 ms []
13 72 ms 72 ms 72 ms []
14 73 ms 72 ms 73 ms []
15 73 ms 72 ms 72 ms []
16 72 ms 72 ms 72 ms []
17 73 ms 73 ms 73 ms []

Does anyone happen to know where the other end of this tunnel is that magically everything from a DC-DC hop to a DC-LA hop are all exactly 73ms?



I'd have thought I didn't need to provide credentials in NANOG, but apparently one stays quiet too long and you're a noob.

First, to those who have given me basic mpls, traceroute and ip primers by off list email, thank you. It's not necessary. I appreciate your willingness to help out the community.

Second, I *know* that the traceroute I pasted a bit of has to do with mpls magic (or similar). That's why I used the word tunnel. I wasn't asking *how* it was done. I'm quiet capable of performing the same magic. I just wanted to know if anyone off the top of their head knew *where* the packets were magically popping back into the ether... LA, Nevada, Denver. That's all. A physical location or a router IP would have been a perfectly wonderful answer.

Again, thank you (all) for your time. Apologies for the distraction. If you aren't someone who knows this very specific piece of information, my message probably wasn't for you.


Hey Deepak,

Sorry, but they're actually right. Read the section on icmp tunneling,
it explains exactly how and why you're seeing this behavior. :slight_smile:

The return packets pop our at the end of the lsp, which is clearly
in LA (or thereabouts, whatever lsrca is probably).