ā05-08-2012 08:43 AM - edited ā03-07-2019 06:35 AM
Hi,
On the Cisco switch MTU is set to 9000 on all ports. Some hosts are configured for MTU as 9000 and some are default 1500. IT's causing problem in the application communications between hosts. Is there anything on the switch side that needs to be configured other that MTU size to 9000.
Please share the experience.
Thanks!
Subodh
Solved! Go to Solution.
ā05-08-2012 09:23 AM
Hello Subodh,
is the Cisco switch used for inter vlan routing ( OSI Layer 3) or only as L2 device?
Is MTU set to 9000 on all L2 interfaces and all SVIs ( L3 Vlan interfaces)?
the issuemay arise because one host H1 can send a packet bigger then standard MTU to an host H2 that has only standard MTU. If all involved network devices support the bigger packet the frame is delivered to H2 where it is dropped
You should verify if an ICMP unreachable packet too big can travel back from H2 to H1 in order to make H1 aware of the reduced MTU of the other endpoint
see
http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml#t4
problems with Path MTU Discovery section
Hope to help
Giuseppe
ā05-08-2012 09:23 AM
Hello Subodh,
is the Cisco switch used for inter vlan routing ( OSI Layer 3) or only as L2 device?
Is MTU set to 9000 on all L2 interfaces and all SVIs ( L3 Vlan interfaces)?
the issuemay arise because one host H1 can send a packet bigger then standard MTU to an host H2 that has only standard MTU. If all involved network devices support the bigger packet the frame is delivered to H2 where it is dropped
You should verify if an ICMP unreachable packet too big can travel back from H2 to H1 in order to make H1 aware of the reduced MTU of the other endpoint
see
http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml#t4
problems with Path MTU Discovery section
Hope to help
Giuseppe
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide