Extremely High Latency on Cisco 1700 Series Router

[devildoc]

Has anyone seen the problem described below?

I have a Cisco 1700 series with two ethernet interfaces (Ethernet and FastEthernet) and a VPN interface module. The ethernet interface is connected to a DSL modem with static IP address assigned to it. The fast ethernet is connected to the internal LAN.

The router has NAT enabled for Internet access from the internal LAN users. In addition, access lists and crypto maps are configured on the router.

After router reload, users were able to surf the internet with no problem. Pinging external IP addresses only takes about 10 - 20 ms. However, 15 minutes after the router reload, internet access becomes extremely slow. Pinging external IP addresses averages about 3700 ms for the replies.

Router utilization remained low with no obvious errors. I have never seen this problem before. Has anyone seen something similar to this scenario? If yes, please advise. Thank you for your help.

JD

[jmia]

Hi Johanny --

This sounds to me more of a service provider issue - Pls. speak to the service provider and ask them to investigate form their end back into your network and see what they say.

Let me know your results,

Thanks --

[devildoc]

I already checked with the ISP. They tested the line with no problem seen. The weird thing is that if i connected the DSL modem directly to my laptop, then the latency is not seen. It worked great like this. However, as soon as i connect the DSL line to the ethernet NIC on the Cisco 1700 series router, then the latency is seen after about 10 minutes of activity.

I am open for other suggestions!

JD

[daveyg]

JD - Do you have a large access list applied?

Other things to look at might be the volume of traffic going out through your link. There could be a lot of internet or mail traffic. Have you tested it from a client while no one else is using the internet? You might try and see what traffic is going out because it may even someone using kaaza or sending large mails.

Gavin.

[devildoc]

The access lists are not long. I have 4 access lists. They total up about 40 lines. The volume of traffic going out through my link is insignificant. I tested it with only one user doing nothing but surfing the Internet, and the latency is as high as 5000 ms or more.

Could this problem be a defective router (more than a year old)? Or a bug in the codes? I downloaded and used the version 2 of the original codes and still had the same latency problem.

Is there anything else that i can check to find out if there is anything wrong with the router's hardware or software?

Any help is appreciated. Thanks.

JD

[cloun81]

Try turn off ip cef.

Check NAT config.

Check routing.

[olorunloba]

What are the input and the output values on the interface connecting to the DSL when the latency goes high. You could try to use NBAR, Netflow, or IP Accounting to diagnose what is going through the router. (NBAR might not be supported though on the 1700). You might also have retransmissions some where. You could dump your show interface.