tlhIngan
join:2002-07-08
Richmond, BC
kudos:1 | Bridged Cisco casuing extreme latency? Here's something I've found strange.
I have BB50 with a bridged Cisco. Lately I started noticing extreme latency (500-1500ms) on it. I thought it was the router, so I'd reboot both (because I found that after rebooting the router, it can't get an IP via DHCP). The problem would be gone for a few days, then return.
On a lark, I decided to reboot just the modem, and after the modem finishes, latency is back to normal again.
Anyone seen this? It's definitely bridged - my router is getting an Internet-accessible IP. But it seems like the modem's routing features are still alive and they're collapsing under the load.
Router's a Netgear WNDR4500.
(Off subject - I have discovered the modem boots up in bateway mode - while I was reoboting both, the router never worked when I power-cycled both. In the end, I determined that the reason is it kept getting a 192.168.100.x address. If I held off a bit, it would get the proper outside IP. Strange.) |
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1 edit | rebooting the modem will reset the established link between the ethernet ports (It could still be either). You need to direct connect for a few days to prove it's not the modem...
A friend of mine has the BB50 Bridged cisco with no problems so it *shouldn't* be an inherent firmware bug. |
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tlhIngan
join:2002-07-08
Richmond, BC
kudos:1 | reply to tlhIngan
Perhaps it was Shaw - given I've had it for months without an issue and it only started in May.
After I rebooted the modem a few days ago and enabled QoS on my router (I never realized BB50 gave me 3Mbps up... but it's good to not exceed it) my latency hasn't gone up. Perhaps Shaw went and did something on the node.
Still, was pretty interesting to find that the modem does issue a private address for 30 seconds or so while it boots up. |
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Cornat
join:2011-10-17
Kelowna, BC | said by tlhIngan:Still, was pretty interesting to find that the modem does issue a private address for 30 seconds or so while it boots up.
This happens on the Motorola modems as well. I believe the IP that it issues is 192.168.10.100. |
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| reply to tlhIngan
said by tlhIngan:Still, was pretty interesting to find that the modem does issue a private address for 30 seconds or so while it boots up.
This is normal for a DOCSIS modem. Most modems will display an info page until the modem connects to the CMTS and grabs its config file which then disables this private IP and info page. |
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| Agreed,
192.168.100.1
and DHCP range starting at .2
You will see this on the SB510x modems too, other providers, you can put in that IP, and see signal levels as well, with Shaw's firmware, you can not, but that is why it is there.
The DPC3825 you can enter 192.168.100.1 when in bridge mode and get to the login screen, but I don't believe anybody has a username and password that will work at that prompt.
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Yes, I am not employed and looking for IT work. Have passport, will travel. |
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tlhIngan
join:2002-07-08
Richmond, BC
kudos:1 | reply to tlhIngan
Well, it's only this Cisco modem that I had a router that managed to grab that address - all the other modems I've used may have issued that address, but the router never grabbed it via DHCP.
Perhaps because the Cisco takes a lot longer to boot up - it only starts handing out the public IP when all the LEDs flash for the second time which is after the connection's fully established.
Still - I don't know why my router can't DHCP acquire from the modem the second time (I reboot router, and clicking renew will not give me an IP until I restart modem. But DHCP renews just fine otherwise). |
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