I have an interface vlan on two 4510 switches. these switches are trunked together. There is a service running across these switches that isnt working and requires large mtu sizes. Pinging between the interface vlans linking the switches over ospf, I cannot ping above 1500. It drops out at 1501.
Any insight into this would be greatly appreciated. Do I need to enable large frames by some means?
>> Any insight into this would be greatly appreciated. Do I need to enable large frames by some means?
Yes, however there are different ways to achieve this.
You can use a global command like
system mtu <size>
(Warning your OSPF adjacencies will flap so you need a maintenance window)
Or you can enable jumbo frames.
You need to ensure that all L2 interfaces in the end to end path are configured and support the increased MTU.
but, first of all you need to understand what MTU is needed by this application to work.
On the other hand you can find the involved hosts likely servers and check their MTU settings.
They have likely a non standard MTU like 9000 bytes and this can cause the issue more then the application itself.
Hope to help
check the effective IP MTU with
show ip interface vlan X
The system mtu 2248 may solve your ping issue between the C4510 in some platforms / IOS versions is needed to be able to use greater packets in the switch TCP/IP stack (the route processor)
Be aware that also L2 ports connecting to servers need an increased MTU to work ( end to end path between the two hosts).
Hope to help
Figured out my issue. Mostly errors on my end. Took the mtu off the linking interfacea and applied mtu 9000 to the trunks between them. Everything is good now..