Regarding no ip route-cache on Cisco 2960

[aj904682013]

The users have been complaining about the network is slowness , after checking each lay2 switches, I found under each vlan the no ip route-cache is configured, the module is 2960, I am not sure if the command is there by default or configured manually, it is configured under the vlan interface only, not under each interface, will this be the reason that causing the slow performance? by the way will there be downtime by removing this command?

Thanks

[Richard Burts]

I believe that the command is there by default. Since ip route-cache relates to processing layer 3 and since the 2960 is a layer 2 switch I am pretty sure that this command is not the cause of network slowness.

HTH

Rick

[aj904682013]

Thanks Richard

so this command is not related to any layer2 devices, any idea what do those layer2 switches ports manage to send packets, guess I should say frame, layer3 is using process, fast and cef, what about layer2

[Richard Burts]

You are on the right track. Layer 3 interfaces use IP addresses to make forwarding decisions for packets and might use process, fast, or cef switching at layer 3. A layer 2 interface on a switch will forward frames using MAC addresses. The switch port looks at the incoming frame, determines the destination MAC address, looks up in the MAC address forwarding table, and makes its decision on where to forward the frame. The closest that we come to something like process, fast, or cef for layer 2 forwarding is that some (old) switches and bridges did the lookup and forwarding in software, and newer switches do the lookup and forwarding in hardware (ASICs).

HTH

Rick

[aj904682013]

Thanks Richard, really helpful

[Rolando Valenzuela]

Do you have any type of erros?

#show logg

Is the switch hitting any threshold?

#show processes cpu history

#show processes mem history

[aj904682013]

Hi Rolando

Thanks for your reply, so far everything looks good, nothing abnormal

[jrdavidson]

Network Latency is hard to troubleshoot.

-Isolate which customers are complaining about slow services

-ID the services(is is just shared drive access or just web access or is it everything accross the board)

If its the entire network, you probably have issues at the core or backbone so start looking for something that changed or is not meshing with the original design baseline.

If its isolated to one leg of the network, you can look at interface counters for errors or protocol implementations(maybe STP reconverged to a new link that is slower or root bridge problems are occuring.

You can also look at the CPU on the switches supporting the laggy hosts.  If its through the roof, then you probably have a loop or broadcast storm.

Hope this helps, but latency is really hard to troubleshoot until you can isolate the problem down.

Also, ip route-cache is just a higher level of switching.  The 2960 is perfectly capable of switching traffic for all of its user ports with the default switching method.

[aj904682013]

The users who are complaining are at call center, theirs PCs are connecting to cisco ip phone, also the 2960 POE switches are 100M port, not G port, and there is only one cable used for trunk (the trunk port is Giga), by the way , if I change the 100M module to Giga module, will this do any help, or add one more cable by etherchannel for trunk

Thanks