On Fri, Jul 31, 2015 at 8:07 AM, John Kristoff <jtk@cymru.com> wrote:
On Thu, 30 Jul 2015 21:18:10 -0500 Jason Baugher <jason@thebaughers.com> wrote:
In one case, when we were having an issue with a SIP trunk, we re-numbered our end to another IP in the same subnet. Same path from A to Z, but the packet loss mysteriously disappeared using the new IP. It sure seems like they are throttling somewhere.
Not knowing how you evaluated the two paths, but if MPLS was not considered, it may have perhaps been due in part to ECMP behavior. While not ruling out UDP limits, it is plausible that the changed source IP address resulted in a less congested path to be chosen.
ding! this sounds like the most plausible answer... I wouldn't expect L3 to limit udp/5060/6061/SIP traffic, as a common carrier that also runs a SIP trunking service they: 1) probably know what SIP traffic is 2) don't want to get bitten being seen as preferring their own network offerings over other external ones (or perhaps accidentally impacting actual customers).