IP-TCP ... incomplete implementation

[Chris Lindblad <cjl@WHEATIES.AI.MIT.EDU>]

    Date: Wed, 20 Jul 88 19:05 EDT
    From: buff@upenn.warminster.cis.upenn.edu (Richard Billington)

    It appears that the version of IP-TCP we have loaded here doesn't handle IP
    fragmentation. We need a fix for this immediately. We are trying to get NFS to
    work, and our central UNIX file server sends a datagram containing all of the
    information in /etc/exports (which is considerable) in reponse to the RPC
    request mntproc-1-export. The resulting datagram is larger than an ethernet
    packet and is hence fragmented, and the Symbolics drops it on the floor. We
    don't believe that IP fragmentation is an optional portion of the IP protocol
    specification.

Symbolics IP-TCP does do reassembly.  It just has a maximum packet size of an
ethernet packet, 1500 bytes.  It will reassemble any fragments as long as the
resulting packet is 1500 bytes or less.  I believe this is allowed by the IP
protocol specification.

I agree that it should also do fragmentation and handle IP packets of up to 16
kilobytes, but in terms of the IP specification, this is optional.

As a workaround, if you can, make your /etc/exports file smaller by using
netgroups.  That puts most of the data in /etc/netgroup instead of
/etc/exports.