Comcast Users

[VOIPoTim]

The Comcast problems have mostly been reported in the SouthEast -- rather frequently in Florida. Rather than flagrantly blocking ports, they may simply be "modifying" TCP/RTP packets (whatever that means) which effectively prevents successful functioning of VoIP adapters -- even though, as my prior post indicated, I apparently can register my PAP2 with Comcast but get an "offline" indication (as opposed to "cannont register").

I'll be back in Boca Raton next week and I plan to research the issue with Comcast. (Read that as "I intend to rip them a new one.")

Here is an example of what we're seeing. We'll get the registration request from an ATA, but they strip the login info from it or we'll get a registration request with it redirecting media traffic to another server we don't own.

Not all the time, just basically every time I've had a Comcast problem, it's been one of those. Then later in the day it just starts working again. Side-by-side on DSL, the DSL would have no issues. It's like they are reconstructing the packets and not getting it quite right.

[dswartz]

Tim, I wonder if this is an artifact of the sandvine traffic shaping crap comcast is doing? If this is some sort of proxy functionality, maybe (as you wonder) they are screwing up other protocols?

[VOIPoTim]

Tim, I wonder if this is an artifact of the sandvine traffic shaping crap comcast is doing? If this is some sort of proxy functionality, maybe (as you wonder) they are screwing up other protocols?

I think it's probably related, yeah.

[N9MD]

...We'll get the registration request from an ATA, but they strip the login info from it or we'll get a registration request with it redirecting media traffic to another server we don't own ... just basically every time I've had a Comcast problem, it's been one of those ... It's like they are reconstructing the packets and not getting it quite right.

Aha! "very interesting ... but dumb!" -- quote from Arte Johnson as the German Soldier behind the bushes on TV's Laugh-In (1968-1973).

So, since I'll be in my Boca Raton FL home from this Sat thru the next weekend, just who do I speak to at Comcast and what do I say -- and do I have any leverage with which to politely and calmly threaten them?

[VOIPoTim]

Aha! "very interesting ... but dumb!" -- quote from Arte Johnson as the German Soldier behind the bushes on TV's Laugh-In (1968-1973).

So, since I'll be in my Boca Raton FL home from this Sat thru the next weekend, just who do I speak to at Comcast and what do I say -- and do I have any leverage with which to politely and calmly threaten them?

Honestly it's not something I'd imagine anyone on the phone would have any knowledge about. I've had Comcast twice now... Once when they took over the Adelphia territory when I lived in Boynton Beach and the other time when they took over Time Warner in Houston.

No problems ever with Time Warner, but Comcast has always been fun.

BTW, enjoy FL. Not sure if you know, but the HostGator office used to be in Boca as well off 441/7. I'll likely move back somewhere in that part of FL later on, but for now we need to go where we can hire CS employees at a reasonable cost and grow our businesses cost effectively. I'm young...plenty of time for FL in the 30s retirement phase.

We're looking at a few solutions...one possibly being port 80.

[gbh2o]

We're looking at a few solutions...one possibly being port 80.

Try a TCP implementation to really foul them up? ;-)

[N9MD]

... but Comcast has always been fun.

BTW, enjoy FL...

We're looking at a few solutions...one possibly being port 80.

Thanks for jinxing me with the "enjoy FL" sentiment. It's rainy and windy and cold -- and I actually had to cancel our tee-off time this morning. Woe's me!

Given my exhaustive (and exhausting) review of scores of posts on the Internet (not just in DSL Reports), i have some understanding of traffic shaping and throttling as well as the Sandvine product. I vaguely understand the appending of a TCP RST command to my VOIP data stream which continually causes a reset command to occur -- effectively preventing me from registering my ATA and SoftPhone. What I don't understand is why GizmoProject, StanaPhone and CallCentric are working well on the Boca Raton PAP2T, all using ports 5060 and 5061 and 5062.

Will a call to Comcast CS yield results? In other words, can Comcast selectively remove the TCP RSTs from an individual customer's service -- or is it all or none --- especially considering that many in SouthEast Florida are having success using "YOU KNOW WHO's" VoIP on PAP2s -- such as Burris who posts in DSL Reports?

Uh oh! Just got the "call to brunch" from my lovely wife. Don't get excited -- she's not making it (G-d forbid) -- we're meeting friends up in Palm Beach Gardens. Hey, maybe the weather's better up their (40 minutes North of us). I'll check back later.

[dswartz]

you're mixing two different things. VOIP does not use TCP, so comcast's forged RST packets are not germane (they use those to hose P2P users). What has been speculated here is that they are (deliberately or otherwise) corrupting various SIP packets. Why this affects some and not others, we don't know.

[N9MD]

you're mixing two different things. VOIP does not use TCP, so comcast's forged RST packets are not germane (they use those to hose P2P users). What has been speculated here is that they are (deliberately or otherwise) corrupting various SIP packets. Why this affects some and not others, we don't know.

Aha, I think. OK, so BitTorrent and RST packets and SandVine and all the stuff I memorized are not relevant to VoIP. Thanks for clearing that up.

I'll be chatting with Comcast CS either Monday or Tuesday -- and report the fruits of my labors (probably lemons) shorthly thereafter.

[dswartz]

Well, yes and no. My understanding is that sandvine is a proxy (sorta) that lets ISPs make all kinds of policy decisions about packets transiting their network. One of the controversial comcast things is to use sandvine to detect when a customer is doing "too much" p2p and inject spoofed RST packets to disrupt new p2p connections. It's entirely possible (and I admit to limited knowledge here) that sandvine could do other things, such as hose non-comcast SIP packets.