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userofdsl
join:2000-07-31
Somerville, MA

2 edits

userofdsl

Member

[General] VoIP + Comcast

Any experiences using VoIP with Comcast in the Boston vicinity?

I used Comcast briefly a while ago. Sometimes in the morning Callcentric was unregistered due to what I suspect was a change of my Comcast IP address overnight; rebooting my phone fixed it. I didn't bother to investigate further before I went back to Verizon DSL, which never does this.
userofdsl

userofdsl

Member

Let me rephrase that:

Has anyone, not necessarily in the Boston area, had any + or - experiences with Comcast and VoIP (other than Comast's own VoIP)? Has anyone encountered issues such as the above?

Thanks.
PX Eliezer704
Premium Member
join:2008-08-09
Hutt River

PX Eliezer704

Premium Member

I'm not served by Comcast (I don't even know if Comcast customers are truly [served] by Comcast) but these may be of note:

Some Vonage users are frustrated about Comcast connection quality (2006)
»www.zdnet.com/blog/ip-te ··· lity/938

Is Comcast Discriminating Against VoIP Providers? (2009)
»www.pcmag.com/article2/0 ··· 4,00.asp

Quality of Service (Vonage and Comcast) (2012)
»forums.comcast.com/t5/Cu ··· /1292195
hwittenb
join:2003-12-20

hwittenb to userofdsl

Member

to userofdsl
I've used Comcast for years, however not in your area. I just have a regular internet account that I've had since they started offering broadband service. They have only changed the ip address a couple of times over many years and that was when I was fussing with my router. I don't have registration problems with CallCentric or any other voip service.
slow mo
join:2002-03-19
USA

slow mo to userofdsl

Member

to userofdsl
I have Comcast + VOIP in Indiana. No problem at all. I can only recall change of IP address once. That's because I changed my modem and they had to provision it.

PS: Comcast service is pretty good here because we also have FIOS available.
u475700
Premium Member
join:2004-02-16
·Callcentric

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I've been using VoIP with Comcast as my ISP in Connecticut for more than five years. With the exception of periodic outages early Monday mornings, reliability has otherwise been good and definitely better than DSL from AT&T ever was. I've not had any VoIP service issues with Callcentric related to Comcast. Nevertheless, while Comcast customer service has improved, it is still below par.

wcweaver
Premium Member
join:2002-02-22
Fort Myers, FL

1 recommendation

wcweaver to userofdsl

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to userofdsl
said by userofdsl:

Let me rephrase that:

Has anyone, not necessarily in the Boston area, had any + or - experiences with Comcast and VoIP (other than Comast's own VoIP)? Has anyone encountered issues such as the above?

Thanks.

I had problems in the Fort Myers, Fl with my VOIP for several months (Aug 2012 to October 2012) using Comcast Internet. I had a problem with the upstream as the party I called or called me would hear my voice all broken up, in many cases totally unintelligible. I could hear the other party perfectly.

I worked with Arne Bolen who is very knowledgeable in this field. We tried variou solutions including several different carriers for both outbound and inbound calls. We even hooked the modem directly to the modem and also tried a soft phone.

Nothing improved. That was when I was going to port to Comcast Digital Phone as my VOIP was basically useless.

Then, one day while trying to get Comcast phone and dealing with porting issues, the problem suddenly went away. I did not complain to Comcast as they would not want to hear about my VOIP problems. I figured if I got Comcast phone, and I had the same problem, then I could complain.

I was almost at the point of getting Comcast phone with a new number and forwarding the incoming calls to my Callcentric account, but then the Comcast problem disappeared. So, I gave up on Comcast phone. They obviously had a network problem that was effecting the VOIP.

Bill
SCADAGeo
Premium Member
join:2012-11-08
N California

1 recommendation

SCADAGeo to userofdsl

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to userofdsl
said by userofdsl:

I suspect was a change of my Comcast IP address overnight; rebooting my phone fixed it.

said by userofdsl:

any + or - experiences with Comcast and VoIP (other than Comast's own VoIP)? Has anyone encountered issues such as the above?

I have encountered this issue, normally on a Monday morning, between 1:00 - 5:00 a.m.

Comcast network maintenance used to leave my router "stranded".

When my router booted, it requested an IP address, a default route, and other information from a Comcast DHCP server.

You can read about DHCP here:
»en.wikipedia.org/wiki/DHCP

Locally, the lease period is for 3 days.

The problem occurs when Comcast switches networks during the lease period.

My router doesn't know that Comcast has switched networks, and it won't find out until it tries to renew the lease (which can be 3 days later) or is rebooted.

I was on four different Comcast networks during one trouble shooting session.

I finally resorted to flashing my router with DD-WRT firmware and using the connection watchdog feature.

DD-WRT:
»www.dd-wrt.com

The connection watchdog feature is accessed via:

Administration tab -> Keep Alive tab

The watchdog can reboot the router when there is a connection failure, or at a scheduled time.
userofdsl
join:2000-07-31
Somerville, MA

userofdsl

Member

Thanks for this info, and to all who responded or will respond.

I have a Linksys router, currently with Tomato. If I switch to Comcast and have this problem I can try DD-WRT if Tomato doesn't have this feature.

wcweaver
Premium Member
join:2002-02-22
Fort Myers, FL

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said by userofdsl:

I suspect was a change of my Comcast IP address overnight; rebooting my phone fixed it.

Locally, the lease period is for 3 days.

Strange having such a short lease period on cable.

I have had the same IP with Comcast for over six months and that is with many many modem reboots.
Quattrohead
Premium Member
join:2005-02-09

Quattrohead to userofdsl

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Works great here in the 413 with Phonepower and VOIPO.
Even the fax works on the VOIPO line
I have a Linksys with Tomato too.

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru to userofdsl

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I have a Comcast 27/7 business connection running a FreePBX server under Hyper-V and my are calls are fine. I am also running a VoIPo ATA that does not use my FreePBX server and it works fine also.

I have 5 static IP's, SMC D3, and a Sophos UTM 9 gateway.

»www.sophos.com/en-us/pro ··· utm.aspx

The Sophos is also running as a VM under Hyper-V.
PX Eliezer704
Premium Member
join:2008-08-09
Hutt River

PX Eliezer704 to userofdsl

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to userofdsl
Comcast system architecture is not standardized across different areas, because things were put in at various times, and because Comcast has bought out various other cable companies over the years.

That's especially true of their purchase of Adelphia Cable which operated in many states.
userofdsl
join:2000-07-31
Somerville, MA

userofdsl

Member

Perhaps there are also differences within a region due to acquisition of divergently architected companies.
PX Eliezer704
Premium Member
join:2008-08-09
Hutt River

PX Eliezer704

Premium Member

Yes, many Comcast areas of Massachusetts were previously Adelphia just a few years ago....

....and conversion proceeded at different rates.

I am [not] a maven in such things, but perhaps some differences still remain.

In fact, in this forum a couple years ago we discussed that the Comcast phone product is not uniform across their territories.
SCADAGeo
Premium Member
join:2012-11-08
N California

SCADAGeo to wcweaver

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to wcweaver
said by wcweaver:

Strange having such a short lease period on cable.

I have had the same IP with Comcast for over six months and that is with many many modem reboots.

I was surprised when I had addresses on four separate Comcast networks within a four hour time span (Thanksgiving week, Nov 2011). Routing was very strange, too, at that time.

During that particular week, I also rediscovered the (not so surprising) fact that there is an inverse relationship between WAF and nagging...
userofdsl
join:2000-07-31
Somerville, MA

userofdsl to PX Eliezer704

Member

to PX Eliezer704
Cablevision, arriving in the 1980s, was the original cable service in Boston and some suburbs, and later became part of Comcast, possibly with intermediate ownership changes.
PX Eliezer704
Premium Member
join:2008-08-09
Hutt River

PX Eliezer704

Premium Member

Fascinating, never knew that.

I am glad that the Dolans of Cablevision did not get their claws on the Boston sports teams!
userofdsl
join:2000-07-31
Somerville, MA

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said by SCADAGeo:

I finally resorted to flashing my router with DD-WRT firmware and using the connection watchdog feature.

DD-WRT:
»www.dd-wrt.com

The connection watchdog feature is accessed via:

Administration tab -> Keep Alive tab

The watchdog can reboot the router when there is a connection failure, or at a scheduled time.

1) Does DD-WRT keep a log of watchdog-initiated reboots you can examine?

2) Can it notify you by email of the reboot?

3) Does it do good QOS for VoIP, like Tomato?

4) I read a while ago about stability issues with DD-WRT. Any problems?

Thanks.
SCADAGeo
Premium Member
join:2012-11-08
N California

SCADAGeo to PX Eliezer704

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to PX Eliezer704
said by wcweaver:

I have had the same IP with Comcast for over six months and that is with many many modem reboots.

I should clarify that the week of Thanksgiving 2011 was unusual, and that I normally received the same IP address.

I never had an issue with VoIP, just the network.
said by PX Eliezer704:

Comcast system architecture is not standardized across different areas, because things were put in at various times, and because Comcast has bought out various other cable companies over the years.

That's a very good point.

Locally, I went from Excite@home -> Comcast@home (they stealth probed systems for servers at that time) -> Attbi.com -> ??? -> Comcast.com.

I'm not sure if there was another operator in between Attbi.com and Comcast.com (I moved from the area).
said by userofdsl:

1) Does DD-WRT keep a log of watchdog-initiated reboots you can examine?

System logging is an option, and can be viewed via Administration -> Commands, and running the command:

cat /var/log/messages

It can be logged to another server if desired.

Something to keep in mind - the date/time stamp will show Jan 1 00:00:xx upon booting. It will show the correct date/time stamp after it syncs via NTP.
said by userofdsl:

2) Can it notify you by email of the reboot?

Directly, no.

Indirectly, it can be added to the startup script (Administration -> Commands).
said by userofdsl:

3) Does it do good QOS for VoIP, like Tomato?

I have no experience with Tomato, so I cannot offer a direct comparison.

I am running DD-WRT v24-sp2 (11/21/10) std (SVN revision 15778), and QoS is working.
said by userofdsl:

4) I read a while ago about stability issues with DD-WRT. Any problems?

No yet.

I have been using it for a year and it has been very stable, but please note that I am not using all of the features. There may be a bug which affects stability, but I haven't triggered it because I'm not using that particular feature.