At 06:09 PM 4/12/2007, David W. Hankins wrote:
On Thu, Apr 12, 2007 at 05:58:07PM -0400, Daniel Senie wrote:
2. It's no longer necessary to manage 1500 byte+ MTUs manually
But for this, there has been (for a long time now) a DHCPv4 option to give a client its MTU for the interface being configured (#26, RFC2132).
Trying to do this via DHCP is, IMO, doomed to failure. The systems most likely to be in need of larger MTUs are likely servers, and probably not on DHCP-assigned addresses.
If you're bothering to statically configure a system with a fixed address (such as with a server), why can you not also statically configure it with an MTU?
Neither addresses interoperability on a multi-access medium where a new station could be introduced, and can result in the same MTU/MRU mismatch problems that were seen on token ring and FDDI. The problem is you might open a conversation (whatever the protocol), then get into trouble when larger data packets follow smaller initial conversation opening packets. Or you can work with the same assumptions people use today: all stations on a particular network segment must use the same MTU size, whether that's the standard Ethernet size, or a larger size, and a warning sign hanging from the switch, saying "use MTU size of xxxx or suffer the consequences."