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zaxcom
Member
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# Posted: 20 Jul 2009 11:16
Is it normal if your modem gets rebooted or loses and regains sync that you must also always reboot your router?
I have tried 2 modems (SB-5120 and CM100) and 3 routers (DI-604, Trendnet and DIR-655) and in every case I must reboot the router anytime the modem restarts or regains sync. Its not a problem if I am home, but when I am not it knocks out my VOIP phones until I can get home to reboot the router. This makes the wife unhappy.
This is not a signal level issue I am talking about. My levels are fantastic. My cable company is undergoing upgrades and they have been knocking out the signal from time to time as they work on their equipment.
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Shnerdly
Moderator
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# Posted: 21 Jul 2009 19:57 - Edited by: Shnerdly
Welcome to the forum zaxcom.
It is not normal to have to reboot the router, however, if they are working on the line in the neighborhood, they may be transferring you to different nodes periodically which could cause you to get a new IP address. This might require you to restart the router to re-establish the connection between the modem and the router because your external IP address is usually passed to the first device connected to the modem, in this case the router.
Check your IP address here after each reboot and see if it's changing.
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zaxcom
Member
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# Posted: 21 Jul 2009 20:15 - Edited by: zaxcom
They have been doing work on the CMTS. This work takes the network down for brief periods of time. When it comes back up I get the same IP, which is normal for TW here. They will give you the same IP almost forever as long as you dont change your MAC.
So even though I am getting the same IP the router acts like it has no idea the network ever went down and just holds the old lease. By rebooting the router, or doing a release/renew it comes back on line.
I dont understand why the routers are not seeing that the modem has rebooted.
As an experiment I tried the same test by going direct to my PC, no router, and I got the same result. When the modem goes down and then comes back up the PC does not see the change and even though it says it still has an public IP it wont pass any data to the modem until I release/renew the NIC.
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Shnerdly
Moderator
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# Posted: 21 Jul 2009 21:16 - Edited by: Shnerdly
If they are working on the CMTS, they may be adding nodes to improve their network in your area which would promote the possibility of changing IP's.
I know the norm is that you will keep the IP for a very long time but in this case it confuses me that your router is having a problem if the IP remains the same. The lease doesn't matter if the modem comes back on with the same IP.
I can only suggest that you confirm that your external IP is remaining the same through these changes. I can tell you for sure that your two posts are from different IP addresses. A new IP is the only reason I can think of that would prevent the router from reconnecting.
I'll give it some more thought though and do a little research.
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zaxcom
Member
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# Posted: 21 Jul 2009 21:25
Well the first post I did from work, so that explains the two IP's. I have the same IP at home that I have had for months and months. In fact the only way I can get rid of it is to change the MAC address.
I have an app that runs on my tool bar that shows my external IP at all times, so I know if it is changing or not.
The CMTS work is to switch over from Motorola to Cisco CMTS units. Nodes were added last fall in the first phase of the work. This is all leading up to DOCSIS 3.0 at some point.
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Shnerdly
Moderator
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# Posted: 22 Jul 2009 09:20
From a networking standpoint, the router should resume it's IP lease when the modem comes back online.
If they are altering their hostname it could cause a problem but most router don't look at that. Another possibility is that they are changing the DNS servers on you.
You could try changing the external IP in the router to static with the same IP and the same DNS servers. It's most likely set to DHCP now.
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zaxcom
Member
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# Posted: 22 Jul 2009 09:32
Router is set to use OpenDNS as its DNS servers. Hostname stays the same all the time too.
I tried to do the static IP using the DHCP supplied numbers but that does not work because the router must first talk to the modem in its local IP range 192.168.100.X before the modem will allow communication on a public IP.
Since it happens to all my routers and direct connected PC's it has to be something with the modem, its the only common thread in whole scenario.
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zaxcom
Member
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# Posted: 22 Jul 2009 18:58
Tried another test today, went down to TW and picked up one of their Ambit modems. Same result. So either its just the way that TW provisions modems, or it something to do with Dlink routers.
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Shnerdly
Moderator
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# Posted: 23 Jul 2009 08:05
You've got me stumped.
There are only three things that change and we already covered them. Your not getting a new IP, your not getting a different hostname and your not getting different DNS servers.
I can't think of anything else that would prevent the router from resuming it's lease.
I generally use either Linksys routers or home made routers so I cant speak to how a D-Link reacts.
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zaxcom
Member
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# Posted: 23 Jul 2009 08:15 - Edited by: zaxcom
It has got to be the Dlink router. I could buy another brand but I am hesitant to do that because Dlink has StreamEngine QOS and I need that for my VOIP phones. As far as I know the only other company that offers Streamengine is Trendnet, but from what I have heard their routers with Stream Engine are just Dlink clones.
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Shnerdly
Moderator
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# Posted: 23 Jul 2009 15:40
What VoIP phones are you using? I use Packet8 and also use VoIP with my T-Mobile phone. It doesn't require anything special in my router.
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zaxcom
Member
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# Posted: 23 Jul 2009 15:51 - Edited by: zaxcom
I have Viatalk. Its not so much them as it is my home environment. I am running 6 computers and 2 of them are my kids gaming machines. When they are gaming it can play havoc with VOIP calls unless the packets get prioritized. StreamEngine does an amazing job of keeping VOIP calls crystal clear while allowing gaming or massive downloads to occur at the same time.
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Shnerdly
Moderator
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# Posted: 23 Jul 2009 15:56
I did some brief research on this StreamEngine QOS. It is a net-accelerator and may actually be your problem. It manages what is going on with your internet connection and may not be able to recover from interrupted service without a reset.
FYI: The Linksys WRT54GS evidently has the StreamEngine QOS as well.
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zaxcom
Member
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# Posted: 23 Jul 2009 16:19 - Edited by: zaxcom
I thought that, so I hooked up my old DI-604 router. No QOS. It did the same thing. I need to get another brand of router in house and see how it behaves. A friend of mine says his Belkin does not have the issue. He is on the same TW system as me. He tried the test of disconnecting the RF cable and letting the modem resync and he says his router came right back up. He is using an ARRIS modem.
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Osirus
Member
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# Posted: 20 Aug 2009 22:30
Is it normal if your modem gets rebooted or loses and regains sync that you must also always reboot your router?
I have tried 2 modems (SB-5120 and CM100) and 3 routers (DI-604, Trendnet and DIR-655) and in every case I must reboot the router anytime the modem restarts or regains sync. Its not a problem if I am home, but when I am not it knocks out my VOIP phones until I can get home to reboot the router. This makes the wife unhappy.
This is not a signal level issue I am talking about. My levels are fantastic. My cable company is undergoing upgrades and they have been knocking out the signal from time to time as they work on their equipment.
It's not normal to have to do that but one thing really glares out at me. You have a D-link router and a model that is known to have serious issues with firmware at the moment. Make sure you are running the least buggy of versions for that model.
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