Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!CS.UCL.AC.UK!J.Crowcroft
From: J.Crowcroft@CS.UCL.AC.UK (Jon Crowcroft)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: trace route to OZ
Message-ID: <8907191243.AA21447@ucbvax.Berkeley.EDU>
Date: 19 Jul 89 11:14:24 GMT
References: <89Jul18.225302hst.89@dorsai.ics.hawaii.edu>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 55



 >>(Sputter) About that hop from ARPANET to MILNET at NASA/Ames. Either the
 >>Munchkins are upon us or the Wicked Witch ain't dead. I conclude the route
 >>to Oz is via US DoD, but who would find that surprising?
 
Dave

yes i was a little surprised at the milnet hop

 >It may be going that way, but it shouldn't be. If my understanding of the 
 >situation is correct, the UK is linked via JVNC. Now, if I run a simple thing
 >like a ``traceroute" to ``jvnc.csc.org" (and Oz is one hop South of here), I get
 >the following:

not from me it aint, the jvnc/uk link is academic traffic - i was
using the uk mod path... but below is right for nsfnet realy (i.e.
Univ of London Comp Center


 >and when I run ``traceroute" to ``nsfnet-relay.ac.uk", I get the following:

 >21  NSFNET-RELAY.AC.UK (128.86.8.6)  3840 ms !  930 ms ! *

 >Up through the seventh hop, it's clear to me what is happening. But after that,
 >I get kind of confused. I can't really tell how many hops there are in between
 >the JVNC gateways and ``nsfnet-relay.ac.uk". What I can tell is that I have
 >a stable RTT of about 250ms between me and the JVNC gateways. But when I try
 >to reach ``nsfnet-relay.ac.uk" with a ``ping", this is what I get:

Torben,

i dont understand all the extra hops either, but between JVNC and ULCC are 2
cisco gateways running X.25 (over a satellite link) which will account
for the extra delay and not a little of the loss...

 >----nsfnet-relay.ac.uk PING Statistics----
 >104 packets transmitted, 88 packets received, 15% packet loss
 >round-trip (ms)  min/avg/max = 930/3123/5270

 >And that is not so good. Even the minimum seems to indicate an RTT of almost
 >700ms across that little pond and even if this is a 56Kbps satellite link,
 >that's pretty stiff. I presume some other gateway is hiding in between plus
 >likely a *very* high load on that line.

also, the cisco at the UK end goes thru an X.25 swicth into a
microvax, which runs IP over X.25 (dont ask why, its history) - all
this does not help a lot - someday, we may pursuade folks here that
X.25 and IP mix like oranges and onions, then (when the line goes to
TAT-8) the performance will go reasonable...

 jon


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