Problems with Comcast / Ambit U10C018 Modem

Posts: 183 · Posted: Tue Mar 10, 2009 11:05 am Post subject:

I have the 5100 or the 5105 and I can't honestly complain. I have comcast and for whatever reason I must be lucky. Our phone service has been nothing but clear. I do have QoS for Vonage's protocols set to the highest setting on my router. I also don't know if that is because we are old Insight customers that were migrated to Comcast about a year ago. I guess it could be my entry point into Vonage's routers as well.

I just did a traceroute from my network to Vonage and I hit the following hops.

1-6 are local Comcast Hops then:

7 pos-0-0-0-0-cr01.nashville.tn.ibone.comcast.net (68.86.90.173) 29.096 ms 28.845 ms 28.454 ms
8 pos-0-4-0-0-cr01.atlanta.ga.ibone.comcast.net (68.86.85.26) 37.052 ms 34.778 ms 36.013 ms
9 pos-0-12-0-0-cr01.mclean.va.ibone.comcast.net (68.86.85.238) 58.082 ms 56.894 ms 56.962 ms
10 pos-0-13-0-0-cr01.newyork.ny.ibone.comcast.net (68.86.85.9 Cool

57.709 ms 57.682 ms 57.111 ms
11 br02.klga1.comcast.vonagenetworks.net (68.86.89.130) 71.500 ms 57.734 ms 57.443 ms
12 10.31.3.253 (10.31.3.253) 57.620 ms 59.448 ms 57.447 ms

13 - 64 are simply stars most likely due to firewalls.

Any other comcasters with good quality see the same path?

Posts: 656 · Posted: Tue Mar 10, 2009 11:13 am Post subject:

Hops 13 - 64 do not exist. That is why they time out. A default traceroute will travel up to 30 hops. It does not stop at the end point unless the IP you traced to has been reached. Your traceroute must be defaulted to 64 hops which is insane.

Hop 12 is Border Router 02 at the edge of Vonage's network connecting to the Comcast IP link. The IP your tracing to does not respond to IMCP type 30(Traceroute) so it will stop at the Border Router.

Posts: 132 · Vonage Forum Senior Joined: Apr 06, 2004 Posts: 132

So getting back to the subject of my original post, I tried to get Comcast to swap out the modem, but after much wasted time and travel, it comes down to the fact that either they do not have any Motorola SB5100 modems, or if they do, they have no idea how to get one for me.

I drove directly from Comcast to Best Buy and found a Motorola SB5101 there, which I purchased in hopes that it would be as good as the SB5100.

I then drove back to the Comcast place and tried to turn in my old modem, but they make that process much more difficult that one might imagine. After another 45 minutes or so, I finally got that done and headed home to install the new modem.

I got it all hooked up, but then I had to call Comcast yet again because although they kept me on the phone for 45 minutes while I was at the Comcast payment center, they did not actually provision the modem at that time.

So anyway, Comcast finally provisioned the new modem and it seems to be working…at least to some extent. My initial quick tests with Vonage were good, although 30 minutes later, I was not able to connect a call from one of the Vonage lines. I did not have time to mess with it at that moment, so I just switched back to DSL, which worked perfectly, as usual.

Following that, I rebooted both DSL and cable modems, the router and all of the Vonage devices and tried to run on Comcast again. It seems to work at the start, but after a while…say 20 minutes, it stops working again. I just tried to place a call a moment ago, and I got a dial tone, and I could dial, but then no rings – just dead air.

It may also be worth mentioning that I called Vonage tech support first. The rep. Kept asking me to do things that I knew would kill our phone connection (since all of our phones are Vonage phones). He called me back a few times, but the third time that he insisted that I do some action that caused us to disconnect, he did not call me back. ’Probably just as well…I don’t think he “got it” anyway.

So after Vonage last night, all day today until now, and about $100, it still doesn’t work.

Any ideas on what to do next?

Thanks,
-Mark

Posts: 81 · Vonage Forum Senior Joined: Sep 26, 2008 Posts: 81

Just curious, were you forth giving with all necessary information to the tech from Vonage?

Posts: 350 · Vonage Forum Evangelist Joined: Dec 04, 2005 Posts: 350

When you were running the test using you cable connection, were you running it through the RV042? If so, can you try connecting the Vonage device directly to the modem, bypassing the RV042, just to test?

The reason that I ask is that in the past, I have seen some RV042 routers do stupid things like drop certain SIP messages, causing call setup failures. If I read your description of the problem correctly, that does seem like what's occurring to you: you're not receiving poor quality audio (choppy, etc); instead you're getting no audio.

Its one of the reasons I decided to not go with an RV042 when shopping around for a router a while back.

Posts: 132 · Vonage Forum Senior Joined: Apr 06, 2004 Posts: 132

Slyster, with respect to the good people in the trenches at Vonage, the tech I spoke to just didn’t know what questions to ask. I answered as best as I could, but t’s just tough to carry on a conversation when the tech keeps asking me to do things that cause our phone call to be disconnected!

Treckologer, I have tested with the Vonage device connected directly to the cable modem, with nothing else connected. I have the feeling that it may work just slightly better like that, but it still has problems. And since the serious issues seem to crop up after a period of time, say half an hour or more, and I am typically not in a position to leave it hooked up like that, that may explain why it seems better when hooked up direct.

Honestly, I think the RV082 is the best thing that has ever happened to my small office. Up time is measured in months whereas I never could get past a few days using any of the routers embedded in Vonage phone adapters. I was reasonably pleased with the way it performed prior to December of 2008. It would dutifully switch between cable and DSL as required, with no intervention on my part. Vonage voice quality (on DSL) is the best that I have ever heard on any Vonage connection and is arguably better, in some ways, than most conventional phone connections. The RV082 does a nice job of managing bandwidth so that other traffic on my LAN has no effect on phone calls. Granted, it never could manage a seamless switchover during a Vonage call, and Vonage never was able to tolerate the router’s “Load Balance” mode, but the “Smart Link Backup” mode served me reasonably well.

When I started having problems with the Comcast modem going offline, Comcast came and replaced the modem. No other system or configuration changes were made, but Vonage has never worked properly on Comcast since then. I really don’t think it’s the router (as such), simply because the same router continues to work perfectly with DSL. IN addition, it used to work fine with Comcast, and before that, with Time Warner. I’m not sure what happened in December, but maybe there was more to it than a simple modem failure. Since replacing the modem with yet another model does not seem to have resolved the problem, that is almost certainly true.

-Mark

Posts: 132 · Vonage Forum Senior Joined: Apr 06, 2004 Posts: 132

VonTechMgr,

I just wanted to put a positive note at the end of this thread.

At your suggestion, I reset my RV082 router to the factory settings. It was not all that much fun to kill all of the phones and the network while I rebuilt the configuration, but I think it may have actually solved the problem. I have to admit that it doesn’t make much sense to me, but if it works, then far be it from me to argue with success!

I’m not really sure how this relates to my earlier observations where the phone device would not work even when plugged directly into the cable modem, but I can only imagine that I was experiencing multiple issues – apparently, both the cable modem AND the router were both causing some problems. I guess I didn’t do enough testing to isolate the new modem from the router, because when I tested it that way this morning, it worked just fine. If you knew me, you would think that I would have known better than to have fallen into that kind of trap.

It was confusing because it continued to misbehave when the router was in the mix, making it seem like nothing had changed. Doubly confusing because the router was routing DSL data just fine, so I almost couldn’t believe that the problem was directly related to the router. And yet, with what you observed, it's hard to imagine how it could have been anything other than the router.

Anyway, I reset the router, and for the last few hours, I have not been able to detect any misbehavior. So my hat’s off to you VonTechMgr – thanks for your excellent assistance.

-Mark

Posts: 132 · Vonage Forum Senior Joined: Apr 06, 2004 Posts: 132

Hey VonTechMgr,

I know its been a while...hope you are doing well.

I seem to have lost the ability to place calls when connected via the cable modem. Is there any way that I could persuade you to help me (as you did before) by watching what happens when I try to place a call?

Thanks,
-Mark