Gigablast/Fiber/Traceroute
Upgraded to Gigablast fiber in AZ a little less than a month ago and everything is working great.
However, I'm curious about the results I always get from traceroute commands. Since this change every site I traceroute to (IPV4) is always 3 hops. It doesn't matter where in the world it's located, it's always 3 hops.
It doesn't matter what tool I use (Windows 'tracert', winmtr, Linux mtr/traceroute) it's always 3 hops.
Here's an example of one to www.berlin.de
> tracert berlin.de
Tracing route to berlin.de [212.45.111.17]
over a maximum of 30 hops:
1 2 ms 2 ms 3 ms ip72-210-58-1.ph.ph.cox.net [72.210.58.1]
2 2 ms 2 ms 2 ms wsip-184-178-206-100.ph.ph.cox.net [184.178.206.100]
3 160 ms 160 ms 160 ms www.berlin.de [212.45.111.17]
Trace complete.
I'm guessing a network guru on here can easily tell me why (whether or not I can understand it is a different issue).
TIA
It's MPLS (Multiprotocol Label Switching).
It's a standard to direct packets in a wide area IP network.
It operates between OSI Layer-2 (data link) and Layer-3 (network). It's often referred to as a layer 2.5 protocol.
Service providers (Cox) deploy MPLS to support service level agreements with guarantee bandwidths (Gigablast).
From the white paper, Revealing MPLS Tunnels Obscured from Traceroute:
"It is well known that MPLS clouds may potentially lead to inaccurate and incomplete Internet maps when performing active measurements using traceroute. In particular, MPLS tunnels may either obscure the underlying path or be incorrectly classified as direct IP links (between IP routers that are not physically adjacent)."
Since switching to Gigablast with MPLS, the paths on the edge of the Cox network will be obscured within a link-layer tunnel. Since it's below Layer-3, there will be no ICMP messages. No ICMP messages...no recorded hops.
