Re: Comcast / Level3 Peering Issues?

[Daniel Corbe <dcorbe () hammerfiber com>]

> On Mar 22, 2018, at 5:48 PM, David Deutsch <ddeutsch () tsicorp net> wrote:
>
> Hey guys,
>
> VoIP provider here with primary connectivity through Level3 in LAX.
>
> For the past week+ we have seen dropped RTP packets between our Level3
> connection and Comcast fiber customers located in Denver and Detroit
>
> Initially we worked under the assumption that something was occuring at the
> customer locations (such as localized packet loss), however we now suspect
> dropped packets between L3 and Comcast. Forcing traffic over to other
> carriers through community strings resulted in no packet loss.
>
> The issue appears to be in the evening and I was hoping either someone from
> L3 network ops or a list member in the know might have some useful
> information.
>
> Thanks,
> David

I’m no expert in the way Comcast run their network, so the following advice needs to be taken with a giant grain of 
salt.

Historically, Comcast have a tendency to run their peering hot.  

It sounds like you’re trying to reach a Comcast wholesale customer.  In which case, steering your traffic around the 
Level3<->Comcast Interconnect by filtering Comcast’s prefixes from your Level3 connection and manipulating your 
community strings is the right move. 

If you’re trying to reach Comcast broadband customers, steering the traffic away from their Level3 interconnect is 
still probably the correct thing to do but with the caveat that broadband cable access is and always has been a 
best-effort service.

-Daniel