Hi, >From: Bob Hinden <[EMAIL PROTECTED]> >Date: Fri, 22 Jul 2005 13:18:24 -0700
> In my personal view, having devices on shared media with different MTU's is > just a bad idea. I think so, but in a real world, such bad ideas are often accepted. In the IPv4 environment, MTU problem is more simple because DHCP has no MTU option. The mechanisms to adjust packet size are PMTUD and TCP MSS negotiation. For TCP applications to the Internet, these mechanisms will work fine. For UDP or ICMP applications to the Internet, almost applications restrict a packet size less than 1500. Of course, NFS uses large packet size, but almost people will not use NFS over the Internet. So, people can use the Internet fine, and enjoy Jumbo Frames in LAN. To make a same situation for IPv6, we must not include MTU option in RA. An interoperability will be down slightly, but we can use Jumbo Frames. If RA includes MTU option, we will get a perfect interoperability about MTU, but cannot use Jumbo Frame. Now, people are accumulating the knowledge about Jumbo Frames. They will learn the trick to use Jumbo Frames for IPv4, and will say, "IPv6 is slower than IPv4, because it disables Jumbo Frames...". I think there are three ways for us. 1) Do nothing. Jumbo Frames is an illegal specification for IEEE 802.3, and there is no de facto frame size also. Wait until IEEE will move, or a de facto standard will be made. 2) Make a new protocol for MTU/MRU discovery/negotiation. Thanks for Mark, Iljitsch or others. 3) Make a memorandum for Jumbo Frames with current implementations. Fix the implicit maximum value of RFC2464, how to enable Jumbo Frames for IPv6, the estimated problems, the implimentation restrictions, and so on. Ryota Hirose Yamaha Corporation -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
