RECOMMENDATIONS What modem to use for Comcast Business

[krzykat]

I've got a client that occasionally has issues with their Surfboard, leading to less than perfect VoIP calls.

I'd like to replace it, and wondered what recommendations people have. Docsis 3.0 modem/router, WIFI not important as they have their own Netgear WIFI router plugged into it. Does Comcast bitch about using other Modems - does having a purchased Static IP matter?

 

[billsimon]

If you have Comcast Business with static IP, then you are required to use their leased modem.

Otherwise any modem on their compatibility list is fine. We are using the Motorola SB 6183 on a Comcast 100/20 business connection and doing multiple voip with video all day long.

 

[krzykat]

If you have Comcast Business with static IP, then you are required to use their leased modem.

Don't know how that can be legal, but seems to be consistent with what my research has found. Let's see if I can find one that has a VPN server built in it

 

[OTA]

My recommendation is to *NOT* use Comcast for business purposes, ever, at least if you value your business. I've seen many people try, but at least in these parts it's a recipe for frustration and disaster.

I'll echo what the others have said -- Comcast is unable to provision Static IPs without their own modem. Why? I have no clue. It's been this way for years.

Let's just say I hit this issue with Comcast a few years back. I needed an additional internet service connection for a client who already had service at that location. 6 WEEKS, many, many, many phone calls, Comcast's order/tech/delivery system were so screwed up that they still hadn't delivered the modem by the time we needed it. I offered to provide a modem and they said they couldn't support it. So, we embarrassed Comcast in a very public way (hint: it involved a Jumbotron) and suddenly Comcast was very responsive.

 

[billsimon]

My recommendation is to *NOT* use Comcast for business purposes, ever, at least if you value your business. I've seen many people try, but at least in these parts it's a recipe for frustration and disaster.

In these parts, it is the only affordable option for small business Internet, especially if you are using VoIP. There is a long-range Wifi provider, there is satellite, and there are dedicated circuits that cost 20x what we pay for Comcast.

We were able to make the most of our Comcast Business connection with our own modem. The DHCP leases from Comcast are 24 hours or better, and you can get five DHCP addresses on one Business connection. Configuring the router to advertise five MAC addresses on the Comcast side gets you those five IPs and as long as you don't shut down for a week, you essentially have static IP service.

 

[krzykat]

In these parts, it is the only affordable option for small business Internet, especially if you are using VoIP. There is a long-range Wifi provider, there is satellite, and there are dedicated circuits that cost 20x what we pay for Comcast.

We were able to make the most of our Comcast Business connection with our own modem. The DHCP leases from Comcast are 24 hours or better, and you can get five DHCP addresses on one Business connection. Configuring the router to advertise five MAC addresses on the Comcast side gets you those five IPs and as long as you don't shut down for a week, you essentially have static IP service.

Yes, I'm in S. Florida and have found similar. I wish there was competition, but there just isn't any affordable options. Now that I'm using wireshark plus nagios, I can now KNOW for certain when the issue is from them. Getting them to buy into it is another story. It's only been in the last year or two that I've found techs that know what the word jitter is. They use speedtest.net and say "See - good upload, good download speed - there's nothing wrong". I had one company that I ended up paying for an ATT DSL link that was used only for their phone lines, not computers so that they could get quality packets and run VoIP.

This current issue that I want to replace their modem on is on occassion, it flaps. Pings will go 80,40,80,40, then after a while, they'll settle in on 40 and life seems good. The other odd thing is that from the last hop to the modem is often 25ms, compared to other clients I've tested at more like 5ms. Oh - and the last hop doesn't flap - it stays consistent at around 35ms, which is why I feel I need to replace their "purchased modem". They said they've got static on it, but I was under impression that you couldn't do static with a purchased modem.

 

[Jake]

Here in Utah I've used Business Comcast for many VOIP deployments. I don't love them but for the price they work quite well. Like everyone has said they will only provision static IPs on their leased modems. I actually read a good post about why they do that. It has something to do with how their network is setup and that if anyone could setup statics on their own equipment it could mess up their network if configured incorrectly. (Obviously, that isn't the technical answer but the gist of it.)

Now, it seems like the dynamic address rarely change here. I've seen dynamic assignments survive service outages and power outages. However, if you want to use your own firewall/router with a dynamic from Comcast you'll have to deal with double NAT issues or ugly port forwarding/DMZ.

However, the latest Comcast Cisco brand modem does have a Bridge Mode. The Comcast tech told me not to use it as it was unstable but I have one customer that I've enabled it on and it does pass the dynamic to my firewall just fine, so far.

To answer your question about modems. A few years ago the Netgear brand Comcast modem basically blocked VOIP traffic. It has now been fixed so Netgear is usually fine. SMC was the brand to go with back then but I think they are phasing them out. Now they will want to shove a Cisco brand on you as it has the wifi and a Comcast public hotspot built into it. I've lately just been requesting the Netgear as all I want from Comcast is a modem and nothing more. My firewall/router behind it will take care of everything else.

One last thing, Krzykat, I'm very interested on how you monitor your network with Wireshark and Nagios. Do you use Nagios to monitor Asterisk? If so how?

 

[krzykat]

One last thing, Krzykat, I'm very interested on how you monitor your network with Wireshark and Nagios. Do you use Nagios to monitor Asterisk? If so how?

Yes - I use Nagios to monitor my PIAF servers, and I love it. The things that I have it constantly monitor for me now include Disk % Available, CPU Load, Ping (packet loss and latency), Peer Registration status. This way, if a client's phone goes off-line, I'm alerted to it immediately. You can really have it monitor anything you want - Great product. I found some references of the port it uses on FreePBX, and rather think at least at some point they were using it for their commercial module that alerted you when you hit disk space limits and such. I'm actually toying with the idea of making a product based on the combination of products where we could monitor systems and alert them whenever there's an issue.

 

[Jake]

Great idea for a product! I'll have to look in to Nagios more. I played with Zabbix but never got very far. I also deploy lots of pfSense firewalls so I'd be interested how Nagios integrates.

Yes - I use Nagios to monitor my PIAF servers, and I love it. The things that I have it constantly monitor for me now include Disk % Available, CPU Load, Ping (packet loss and latency), Peer Registration status. This way, if a client's phone goes off-line, I'm alerted to it immediately. You can really have it monitor anything you want - Great product. I found some references of the port it uses on FreePBX, and rather think at least at some point they were using it for their commercial module that alerted you when you hit disk space limits and such. I'm actually toying with the idea of making a product based on the combination of products where we could monitor systems and alert them whenever there's an issue.

 

[krzykat]

I"m a big fan of PFsense as well. What would you want Nagios to monitor on it for you?

 

[Jake]

Basically, if there is high latency or a down interface. I imagine other stats would be nice but not as necessary. I noticed that the NRPE addon package for Nagios was re-added to the 2.3 version.

 

[krzykat]

Oh - I've only started using it the past month, so I don't know what they had prior. But sure, the NRPE is mandatory in my way of thinking.