Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ncar!boulder!daemon
From: dfk@cwi.nl (Daniel Karrenberg)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: 1Mb memory constraints in router?
Message-ID: <24662@boulder.Colorado.EDU>
Date: 13 Aug 90 12:11:20 GMT
Sender: daemon@boulder.Colorado.EDU
Lines: 45


  > The cisco comes with 1Mb of memory. 

Well the CSC3 comes with 3MB of memory.  You can also add Multibus
memory although CISCO (at least the Dutch distributor) won't tell you. 
This is of course slower than the memory on the processor card.  But the
memory management keeps them separate and takes Multibus memory only if
it really needs it (for certain non-MCI interfaces) or when processor 
memory runs out.

  > When I do a show mem, I find about 450K total bytes and of that about
  > 100K-200K in use, leaving between 200-300K available.  What has happened
  > to the other 500K?  Is that for the software? 

The software is loaded from EPROM (or your favourite TFTP server) into
RAM.  I am told that 8.2 will have the option of running it from EPROM. 
In my eyes a big plus! 

  > How much room will be taken by a full 1023 node Decnet area routing
  > table?  How much room does each access list take up?  How much room do
  > IP routing tables take up (RIP, IGRP)? 

I have only a vague idea about this.  It would sure be nice if CISCO
published some facts.  It makes "engineering" networks somewhat less
trial and error. What are those 740byte chunks of memory for instance? 

  > Have people hit the wall yet of no more memory?  
  
Yes, your's truly has managed to by turning on moderate IP accounting
(threshold 1000). I now read out the accounting every five minutes and
don`t loose too much data this way. I also have populated some of the 
empty sockets on my NVRAM board to give me another 49152 bytes of
safety cushion. CISCO sells this as CSC-MT "Enhanced Memory Card".

  > What type of error
  > messages does the cisco produce when one runs of memory? 

Well none in particular maybe because there is no memory to log anything :-(.
The thing I watch is the "show buf" output and look for failures
due to memory shortages.  And "show mem" gives you clues about the
state of things as well.

Daniel Karrenberg                    Future Net:  <dfk@cwi.nl>
CWI, Amsterdam                        Oldie Net:  mcsun!dfk
The Netherlands          Because It's There Net:  DFK@MCVAX