Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!ndcheg!ndmath!eggers
From: eggers@ndmath.UUCP (Mark Eggers)
Newsgroups: comp.dcom.lans
Subject: Performance problems with a DESPR
Keywords: performance questions (long)
Message-ID: <1349@ndmath.UUCP>
Date: 27 Mar 89 17:00:40 GMT
Organization: Math. Dept., Univ. of Notre Dame
Lines: 76

I have the following configuration set up, which seems to be 'legal'
according to DEC's Network and Communications Buyer's Guide.

+----------------+
|     DELNI      |
+----------------+
  | | | | | | | |
  | | | | | | | +---p4200 router
  | | | | | | |
  | | | | | | +-----ACS 9310-----IBM 3033
  | | | | | |
  | | | | | +-------Annex terminal server
  | | | | |
  | | | | +---------Cayman GatorBox
  | | | |
  | | | +-----------Mac II running A/UX (only, no Mac OS)
  | | |
  | | +-------------microVAX II running Ultrix 2.2
  | |
  | +---------------Compaq 286 running Excelan's LanAlyzer
  |
  +-----------------DESPR (one port version of a DEMPR)
                     |
                     |
                     +------Convex C120
                     |
                     +------Convex C120
                     |
                     +------Convex C220

The problem:

	As long as I telnet, rlogin, ftp, etc. between the three
Convexes on the thinwire Ethernet, performance is what one would
expect (no noticable delays in telnet IO, 50 - 100 K file transfer rates).

	As soon as one of the Convexes attempts to go through the
DESPR, performance becomes 'terrible' (delays of one to two seconds
at odd times in telnet IO, ftp of 3 - 10 K).

Some other facts

1.	Performance on the 'DELNI' side is reasonable (no noticable
	delays in telnet IO, ftp of 35 - 100 K).

2.	Replacing a Convex with the Compaq does not change the results.
	Compaq performance to devices on the thinwire Ethernet are
	fine, through the DESPR are terrible.

3.	A Convex directly on the DELNI performs well.

Notes on configuration

1.	We run both DECnet and TCP/IP. The microVAX II is the 
	DECnet - TCP/IP gateway for the campus, and there are
	DNA routing packets zipping about on the local net.

2.	The p4200 is set to broadcast RIP on this subnet, and
	the microVAX II runs /etc/routed. Both are probably
	unnecessary.

3.	All devices understand subnets and are configured for it.

4.	No other device (except the microVAX II) is running either
	/etc/routed or rwhod.

5.	All devices on the thinwire Ethernet are connected via
	DESTAs (thinwire transceivers) and 50' of transceiver
	cable. The thinwire Ethernet is properly terminated.

Any thoughts on this problem would be greatly appreciated. Right
now, we have removed the terminal server, DESPR, and Compaq in
order to make room for the three Convexes. Needless to say, I would
like all of these devices (plus 2 NeXTs) on the net.

/mde/