Real life example of providers that's running own BGP. And did not set
it up correct or didn't see the problem. This example will show a SIP
provider that we get sip trunks from and what happens when they not got BGP
routing right. Our customers started complaining that phone calls had jitter
and some times was disconnected. Just before this problem we upgraded all core
routers to latest firmware and for sure I started to get suspicious that this
was the problem. But after some troubleshooting I went over to be suspicious
for the SIP provider. I started to do some tests for one of the SIP server at
provider side (we hade up to 300-350ms). And I could see we had very long
respons time from our side. So next step was to talk to SIP provider and ask
them to do tests. So they did tests and came up that they had no problem
(13-25ms). Now you really start thinking it's your problem. But after one or
two hours. I call SIP provider again and start to do some detective job talking
to them. After littel talking they saying that they just installed I new
Upstream and the are running ther own BGP and use the same Upstream provider.
Now I start to understand the problem, but how will I prove it for them (SIP
Provider). I call Upstream provider and explain the problem and ask if they
could do tests and after two days they call me back and say tey find problem
and had prove for it.
THIS IS THE ANSWER
FROM UPSTREAM PROVIDER:
Nothing in
troubleshooting indicating the failure of the customer (US). SIP provider has
asymmetric routing for the moment when they only send traffic to their drop-off
in City X but the Shortest Path to the route reflector of Upstream provider
located in Stockholm and traffic routed then via Kista. As this debugging can
not be driven by the (US) against Upstream provider and SIP provider must check
its routing. Or make an Error reporting themselves to Upstream provider.
Tools used for troubleshooting:
- traceroute or tracert
- PingPlotter https://www.pingplotter.com/
Now I only need to get SIP provider to understand they doing it in wrong way
