Jack brings up a good point. MTU is basically pointless since packets never traverse any real interface....... So in theory the size can be anything...
> Date: Wed, 17 Nov 2010 15:02:22 -0600 > From: jba...@brightok.net > To: deric.kwok2...@gmail.com > Subject: Re: mtu question > CC: nanog@nanog.org > > On 11/17/2010 11:08 AM, Deric Kwok wrote: > > Hi > > > > I just see that the mtu in lo is different from standard eth 1500 > > > > Any meaning of it? > > > > You transfer huge amounts of data on loopbacks similar to sockets. > Supporting large MTU's is appropriate, and given the virtual nature of > loopbacks, is probably generally designed to handle the buffers that > transfer the data. > > > > How about cisco / juniper loopback? > > > > Thank you so much > > Juniper M120: Type: Loopback, MTU: Unlimited > > Cisco 7206 12.2SRE: MTU 1514 bytes, BW 8000000 Kbit/sec, DLY 5000 usec, > > > Jack >