IPv6 fc00::/7 ??? Unique local addresses

Jack Bates jbates at brightok.net
Sun Oct 24 11:09:28 CDT 2010

On 10/24/2010 5:05 AM, George Bonser wrote:
> And speaking of changing MTU, is there any reason why private exchanges
> shouldn't support jumbo frames? Is there any reason nowadays that things
> that are ethernet end to end can't be MTU 9000 instead of 1500?  It
> certainly would improve performance and reduce the packets/sec and
> increase performance on latent links.  Why are we still using 1500 MTU
> when peering?  Is there any gear at peering points that DOESN'T support
> jumbo frames these days?
Probably no reason at all, though probably little perceived benefit. 
1492 is common enough that google/youtube already runs lower MTU's just 
to avoid common broken PPPoE setups (which often could run higher MTU, 
but weren't configured that way).

Not uncommon for cell companies to request 1600 MTU or more for their 
layer 2 transport, which one vendor had to custom patch 1648 into their 
gear to even support that much. Of course, it will be lowered by a 
variety of tags/tunnels/etc by the time it gets to the cell phone.  It 
cracks me up that SONET interfaces default 4470, and ethernet still 
defaults to 1500. I've yet to see an MTU option in standard circuit 
setup forms, which would indicate to me that asking for a higher MTU 
might get me one extra link before dropping back to 1500ish.


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