nanog mailing list archives

Spectrum Network Engineer (Legacy TWC/RR) ?


From: Gabriel Kuri <gkuri () ieee org>
Date: Wed, 11 Mar 2020 06:45:18 -0700

Any Spectrum/Legacy TWC engineers on the list that could contact me off
list in regards to a network issue in the Los Angeles area that first tier
support is clueless about and unwilling to escalate?

To quickly summarize, it appears port 5060 (SIP traffic) is blocked at very
specific nodes within the Los Angeles area. Yes, SIP ALG is turned off in
the router and cable modem, Techs have been out multiple times to put in
different cable modems to no avail. Swapping the same location over to a
fiber or DSL connection with an alternate provider makes the issue go away.

It feels like there is a piece of equipment beyond the cable modem that is
either mangling or blocking SIP traffic. The issue is not everywhere in the
Los Angeles area on Spectrum/TWC, only a few sites from what we've seen. I
can provide specifics if someone would kindly contact me off list. We'd
like to get this resolved and first tier support says they have no way to
escalate.

Thanks ...

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