nanog mailing list archives
Re: IPIP-tunnel with 1500 MTU
From: "Stephen Sprunk" <ssprunk () cisco com>
Date: Thu, 11 Jan 2001 16:52:16 -0600
Thus spake "Mikael Abrahamsson" <swmike () swm pp se>
(config-if)#tunnel mode gre ip (config-if)#mtu 1500 % Interface Tunnel1 does not support adjustable maximum datagram size
router(config)#in tun0 router(config-if)#mtu 1500 % Interface Tunnel0 does not support adjustable maximum datagram size router(config-if)#ip mtu 1500 %Warning: MTU set 1500 is greater than default 1476, fragments will happen
I believe this is only true if you have serial links that support MTU 1500 all the way between the two routers doing the tunneling, right?
Nope. With fragmentation of the GRE packet, your tunnel MTU can be greater than your real MTU. S | | Stephen Sprunk, K5SSS, CCIE #3723 :|: :|: Network Design Consultant, GSOLE :|||: :|||: New office: RCDN2 in Richardson, TX .:|||||||:..:|||||||:. Email: ssprunk () cisco com
Current thread:
- IPIP-tunnel with 1500 MTU Mikael Abrahamsson (Feb 24)
- Re: IPIP-tunnel with 1500 MTU Valdis . Kletnieks (Feb 24)
- Re: IPIP-tunnel with 1500 MTU Mikael Abrahamsson (Feb 24)
- RE: IPIP-tunnel with 1500 MTU Craig Holland (Feb 24)
- <Possible follow-ups>
- RE: IPIP-tunnel with 1500 MTU Mikael Abrahamsson (Feb 24)
- Re: IPIP-tunnel with 1500 MTU Stephen Sprunk (Feb 24)
- Re: IPIP-tunnel with 1500 MTU Mikael Abrahamsson (Feb 24)
- Re: IPIP-tunnel with 1500 MTU Valdis . Kletnieks (Feb 24)