Buy or Renew
Buy or Renew
Cisco + Splunk: It’s a new day for your data. Learn more.
 
cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Search instead for 
Did you mean: 
cancel
Start a conversation
3235
Views
0
Helpful
1
Replies

Configure GRE Tunnel on 3560 switch

curtis03_2
Level 1
Level 1

‎02-18-2010 01:37 AM - edited ‎03-04-2019 07:32 AM

Hi

I currently have a GRE tunnel terminating on 2xold 3640 routers which I am to replace with 3560 switches.

The current tunnel has an 'ip mtu size' of 1476 to allow for the GRE header of 24 bytes. Initial testing has indicated the MTU size is not configurable on the tunnel interface of the 3560 - could someone please explain how the 3560 switch forwards packets with a max 1500 bytes MTU across the tunnel?

Any help greatly appreciated!

Labels:
0 Helpful
1 Reply 1

Giuseppe Larosa
Hall of Fame
Hall of Fame

‎02-18-2010 02:54 AM

Hello Curtis03,

be aware that a GRE tunnel is supported only on software on a low end multilayer  switch like C3560.

>> could someone please explain how the 3560 switch forwards packets with a max 1500 bytes MTU across the tunnel?

the resulting GRE packet will be fragmented in software as any other GRE packet.

Hope to help

Giuseppe

0 Helpful
Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Customers Also Viewed These Support Documents
Review Cisco Networking products for a $25 gift card