Equipment (Modems,Gateways)
Modems, Gateways, and Networking Devices
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SMCD3G - Internet Drops

We have had a reoccurring issue that is driving me mad and I'm hoping I can find some help here. Every 1-2 weeks it seems like something happens where our internet will start having really bad ping times and then eventually drop. It won't come back unless/until we reboot the modem (or maybe if we waited longer, but typically people are screaming bloody murder the second it start stalling out). This impacts devices connected via Wi-Fi as well as non-Wi-Fi (VOIP phones).

 

I've called support on this issue multiple times. Almost without fail I've been told that it must be something on our end. It can't be. It has happened with varying staff presence (so it's not like one person's laptop has malware chewing up the bandwidth), and with no less than three equipment changes on our part. We're currently using a Cisco router and Unifi WAP that is identical to four other locations that happily maintain their internet connections without this frustrating drop issue.

 

I had hoped with the most recent switch to the Cisco router that things would improve. I hoped that the Wifi router we had been using just couldn't deal with the traffic (we've increased in size from an office of 3 to an office of 10 rather quickly). Unfortunately, it hasn't seemed to have had any impact.

 

The positive thing about the router change is that the logs are a little more informative. I can see that the traffic looks normal on our side - nothing that should be causing a bottleneck on the bandwidth or anything.

 

Has anyone else experienced this issue? Is it something with this model of modem? Unfortunately over the summer we tried upgrading to a different model of modem (different issue/reason) but the Netgear CG3000DCR that we were provided at that time is incompatible with our phone system (something to do with SIP ALG isn't ever effectively disabled and/or there's no true bridge mode).

 

Thanks in advance for your advice and input!

Brenda

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Re: SMCD3G - Internet Drops

As a followup/additional question: What are the other modem options for business class customers? And/or does Comcast allow BYOM? (bring your own modem)?

 

Thanks!

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Re: SMCD3G - Internet Drops

Hello tbbm and welcome,

 

Please see my comments/questions below. Thanx.

 

 

We have had a reoccurring issue that is driving me mad and I'm hoping I can find some help here. Every 1-2 weeks it seems like something happens where our internet will start having really bad ping times and then eventually drop. It won't come back unless/until we reboot the modem (or maybe if we waited longer, but typically people are screaming bloody murder the second it start stalling out). This impacts devices connected via Wi-Fi as well as non-Wi-Fi (VOIP phones).

 

You need to first do the following:

1. Log into your SMC and check out the Gateway Summary.Cable Modem, schrol down to the upstream and downstream bonding tables, copy them and reply here with them. This information tells if your signaling or cabling needs adjustment to allow consistent Internet service, for starters. 

2. Please let us know if you are using a Comcast Static IP address and if so, which device(s) are using it(them). If not, then click on LAN, and make sure your leasetime=forever, and your DNSs = 75.75.75.75 and 75.75.76.76, then click apply. If you have your SMC LAN DHCP server 10.1.10.1 disabled, please let us know this, too.

 

 

I've called support on this issue multiple times. Almost without fail I've been told that it must be something on our end. It can't be. It has happened with varying staff presence (so it's not like one person's laptop has malware chewing up the bandwidth), and with no less than three equipment changes on our part. We're currently using a Cisco router and Unifi WAP that is identical to four other locations that happily maintain their internet connections without this frustrating drop issue.

 

Okay, by the just above it sounds like you are just using a Cisco wireless router and an Unified WAP for wifi extension, please confirm this. We need to know if your Cisco wireless router is using a Comcast static IP address and if it is not, then what 10.1.10.XXX IP address is it currently using? Does this Cisco router also handle your VOIP processing and if not, how is this networked? 

 

I had hoped with the most recent switch to the Cisco router that things would improve. I hoped that the Wifi router we had been using just couldn't deal with the traffic (we've increased in size from an office of 3 to an office of 10 rather quickly). Unfortunately, it hasn't seemed to have had any impact.

 

The positive thing about the router change is that the logs are a little more informative. I can see that the traffic looks normal on our side - nothing that should be causing a bottleneck on the bandwidth or anything.

 

So, are you saying that the Cisco does not have any load balancing enabled? Please confirm this.

 

Has anyone else experienced this issue? Is it something with this model of modem? Unfortunately over the summer we tried upgrading to a different model of modem (different issue/reason) but the Netgear CG3000DCR that we were provided at that time is incompatible with our phone system (something to do with SIP ALG isn't ever effectively disabled and/or there's no true bridge mode).

 

You must understand that if your VOIP phone system is using the standard SIP ports like 5060 for messaging, instead of using some internal ALG subnet-router that changes the ports like 12345, then you must make absolutley sure that those ports are open within the SMC on the VOIP device IP Address.  If not, then you phone intranetworking it will not work. This is the same thing with your VOIP system/server always should use a static IP address so your phones can always access the VOIP server, Phones, etc. having the same IP addresses across the board.

 

Look forward to hearing from you. 

 

 

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Re: SMCD3G - Internet Drops

Rich,

 

   As my other post mentions, our SMCD3G is in true bridge mode, so I don't see how I can log in to give you those tables. Please let me know if there's a way. It seems to me that perhaps the fact that it's in TBM makes this bit moot.

   We are not using a static IP address.

   We are not using a Cisco wireless router - just a Cisco router (not wireless).The internal IP of the Cisco router is 10.1.30.1. (255.255.0.0 subnet)

   Our VOIP system is via OnSip, which is a hosted PBX. The only on-site equipment is the phones and there's no configuration on the router managing the phones, it's just passing the traffic.

    There's no load balancing enabled. It's just a router with a plain jane configuration.

 

    In my web searches on the SMCD3G I seem to find that I'm not alone in my frustrations. Some folks indicate that this router is not capable of handling business level use. While your post regarding my question of logging into the modem when it's in true bridge mode indicates that it's "only a dumb pass-through", the fact that our problems have persisted both before and even after changing to TBM and in the face of having replaced all of our internal equipment and is always solved by rebooting the modem indicates to me that it must be doing something with the modem itself causing our frustrations.

 

    Thanks again for your time and assistance. Also, I would be interested to learn if putting a 3rd party modem in place is an option.

 

 

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Re: SMCD3G - Internet Drops

I wanted to check in and see if anyone is still reading this thread. I'm still hoping for answers!

 

Thanks!
Brenda

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