Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!rice!sun-spots-request
From: ag@cel.co.uk
Newsgroups: comp.sys.sun
Subject: Re: How does SUNRPC/UDP work?
Keywords: Networks
Message-ID: <2336@brazos.Rice.edu>
Date: 20 Oct 89 15:04:54 GMT
Sender: root@rice.edu
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 8, Issue 170, message 1 of 5

In article <1903@brazos.Rice.edu> murthy@thir.cs.cornell.edu (Chet Murthy) writes:
>X-Sun-Spots-Digest: Volume 8, Issue 151, message 2 of 15
>
>Well, I got some answers back.  It seems that SUN has a limit of 8kBytes
>on the size of a UDP packet.  
>So the thing to do, I suppose, is to add a minimal functionality to SUNRPC
>to do packet fragmentation/reassembly for meduim-length (8-16Kbytes)
>messages, and for longer messages, use TCP.
>Does that sound right?

It seems  as  though Sun  are already  doing this  with yellow pages.
Most of the YP interogation routines use UDP, as any  single YP entry is
rarely more than a few hundred bytes  long.   However the "yp_all" call (
retrieves entire contents of a map  ) apparently  uses TCP due to the
potential length of maps.

I have found this  out the  hard way  as our  network is experiencing
problems with the "ypcat" command  when running  in a  YP domain with
multiple servers. When a client is bound to a slave server the ypcat
sometimes fails reporting:

     "yp_all - RPC clnt_call (TCP) failure: RPC: Unable to receive; 
      errno = Connection reset by peer"

None of  the  other  YP  functions are  affected in  anyway when this
occurs.

As Sun haven't come up with much I wondered if some  bright spark out
there has ever seen anything like this before.

Thanks in advance for any help.

	Andrew R. Gray --- Crosfield Electronics Tel: 0442 230000 ext 3406
					   e-mail: ag@cel.uucp,ag@cel.co.uk