[c-nsp] MTU over L2TPv3 tunnel

[Mikael Abrahamsson]

On Thu, 28 Feb 2008, alex at alsn.be wrote:

> When i test the connection (RFC 2544) i get the result i expect 
> +/-90Mb/s as long as the packet size is smaller then 1518. Once the 
> packet size is 1518 the cpu of one of the two routers gets to 100% and 
> the throughput lowers to +/-30Mb/s after about 30 seconds.

You could try to use "ip tcp adjust-mss 1420" or alike on the LAN 
interface (where the traffic going into the tunnel is coming from). If 
your traffic is mostly TCP based then the packets will be small enough to 
not be fragmented, and your "ip mtu 1500" on the tunnel still allows 
fullsize packets to go thru if needed (if it's UDP for instance).

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se