Thoughts on increasing MTUs on the internet

Fri Apr 13 09:03:53 UTC 2007

> No, I doubt it will change.  The CRC algorithm used in Ethernet is 
> already strained by the 1500-byte-plus payload size.  802.3 
> won't extend 
>   to any larger size without running a significant risk of the CRC 
> algorithm failing.

I believe this has already been debunked.

>  From a practical side, the cost of developing, qualifying, 
> and selling 
> new chipsets to handle jumbo packets would jack up the cost of inside 
> equipment.  What is the payback?  How much money do you save going to 
> jumbo packets?

I believe that the change is intended to apply to routers and the
ethernet switches that interconnect them in PoPs and NAPs and exchange
points. Therefore the cost of a small chipset modification is likely to
be negligible in the grand scheme of things.

As for numbers, it is not dollar figures that I want to see. I would
like the people who have jumbo packets inside their end-user networks to
run some MTU discovery and publish a full MTU matrix on all paths on the
Internet. That way we can all see where there is end-to-end support for
large MTUs and people who want to make buying decisions on this basis
will have something other than vendor assurances to show that a network
supports jumbograms. 

--Michael Dillon