🚀 go-pugleaf

In article <qq7d1l0@rhyolite.wpd.sgi.com> vjs@rhyolite.wpd.sgi.com (Vernon Schryver) writes:
>In article <1992Oct7.150707.29127@awdprime.austin.ibm.com>, will@vulcan.austin.ibm.com (Will Fiveash) writes:
>> In article <qncmi00@rhyolite.wpd.sgi.com> vjs@rhyolite.wpd.sgi.com (Vernon Schryver) writes:
>> >The only IP fragmenting that an FDDI-ether bridge will usually need to
>> >do is of UDP packets.  UDP packets are datagrams, and have no sequence
>> >numbers of any kind.  If you don't have FDDI-ether-FDDI networks, the
>> >initial MSS negotiation in TCP will pick 1500.  This is consistent with
>> >the TCP/IP lore (and RFC) that considers fragmenting harmful.
>> 
>> I am somewhat confused about the statement concerning MSS negotiation.
>> My understanding was that if the two connecting systems were on the
>> same physical network then the MSS was the MTU of the interface -
>> TCP/IP header length.  If they were not on the same physical net, i.e.
>> router(s) involved, then the MSS was 536.  This is what I am reading
>> from Doug Comer's book "Internetworking with TCP/IP".
>
>Are we disagreeing?  I don't think so.
>

You are right.  As I reread the above statements, I see that it is a
FDDI-ether BRIDGE that you were discussing so a TCP connection across
it is transparent as far as the MSS negotiation is concerned.  Given
this, it makes sense that the MSS will be the smaller of the two i.e.
1500 in this case.

Thanks for the info.

>Vernon Schryver,  vjs@sgi.com


-- 
Will Fiveash,  "My opinions above, facts below."
Internet:  will@austin.ibm.com