Packet Loss

[usmany]

Please guys help me out on my network problem.

I have a cisco router 3640 series with ios 12.1 (5) T... just recently when i started experiencing a slowdown on the network when browsing the net... I troubleshooted the network to see if there is a problem of virus or network card... I thought the first time was my serial interface card connecting the network to my gateway (provider)... even planed purchasing new cards (wic-1t+1e2w)...

A friend adviced me to use bandwidth monitor and monitor the bandwidth utlization... percentage of my utilization is less than the packet loss with about 20%... the packet loss is about 100% while response time is just 80% or so.

Please, what do you this is responsible to the loss of packet?
Is the vulnerability on the product i.e. cisco 3640 series router?
If yes, I need your help guys on what to do

Thanks

[lessthanzero]

www.cisco.com has extensive troubleshooting guides. you need to check them out.

the cause of the problem will likely only be found after you isolate the symptoms. You have to approach the problem systematically by looking at:

1. the interfaces - check for incrememting error counters after clearing all counters. also check for drops in your interface queues.
2. is your connection point to point or frame? look at correlating diagnostics....
3. what is the utilization of the cpu/memory? is IP input high?
4. what do the arp and route tables look like?
5. look at the topology - can you ping the next hop after/before this router? how far does a traceroute go before dying (and is that normal or abnormal)?

that should get you started...but here some specific commands:

sh int
sh frame pvc (if using frame)
sh proc cpu
sh arp
sh ip route

also, don't be afraid to install syslog somewhere if you haven't (i like kiwi) and send snmp traps and level 7 logging to the syslog server. you might catch some interesting errors showing up.

Lastly, look at what your router is connected to on the private side. A hub...a switch? Running 100/full or 10/half? Error counters on the l2 device...etc., etc...

Cheers,
<0

[usmany]

I found where the problem is coming, the fastethernet is set while there is no connection to it but transmitting more than the ethernet is transmitting with about 48% while the ethernet is just transmitting just 28 to 30%.

I shutdown the fastethernet and removed its ip, then its stopped dropping/lossing packets, means packet loss is solve. But I still want to be clear with things guys, how can one be good in troubleshooting network problems? any idea please?

Thanks for the assistance essthanzero I will always need your assistance if i have any problem if you wont mind?

Also thanks to Antionline for providing us with this greatest means of communicating and bringing all knowledgebles gurus to share their knowledge with newbies like me and network amatuers. God bless us all guys

[lessthanzero]

if you're interested in learning how to troubleshoot these types of issues, you should really take a look at the cisco documents. They're invaluable in providing not only resolutions, but also clues in regards to what steps to take, where to look for evidence of specific problems, etc.

also, you're always free to post new threads or send private messages...

Cheers,
<0