32 MB RAM for Cisco 2500 series

32 MB RAM for Cisco 2500 series

Post by Jason Aaron » Fri, 10 Jan 1997 04:00:00



   Dear Cisco Users,
   I have a frame-relay spoke-hub configuration with a 2501 as the
hub.   It currently has 16MB of RAM, with 15MB of RAM used (show
proc mem).  I want to upgrade to a 32MB SIMM.

   1.  I don't see 32MB RAM supported in the 2500 series product guide.
   2.  While not supported, while it work ?
   3.  Anyone know a supplier or memory type ?
   4.  What issues will I face ?

   Jason Aarons
   Field Srvc Engr
   Sprint

 
 
 

32 MB RAM for Cisco 2500 series

Post by Terry Kenned » Sat, 11 Jan 1997 04:00:00



>    1.  I don't see 32MB RAM supported in the 2500 series product guide.

  True.

Quote:>    2.  While not supported, while it work ?

  Nope.

Quote:>    3.  Anyone know a supplier or memory type ?

  See #2

Quote:>    4.  What issues will I face ?

  Not enough address lines.

  I'm told by the Cisco folks that the reason for the things that look "ob-
viously brain-damaged" in retrospect on the 25xx are because it was Cisco's
first custom VLSI implementation of the IGS architecture and they didn't want
to make major changes. This seems to make sense.

  This means that if you want more than 18MB DRAM (16 main + 2 I/O) you need
to move out of the 25xx family. However, since probably the only reason for
wanting that much memory is maintaining a large routing table, you should
know that the 25xx doesn't really have enough CPU power to handle updates for
full routing.

  I'd look at your show mem output and see where all the RAM is going - if
you're not doing full routing, I think you have a memory leak.

        Terry Kennedy             Operations Manager, Academic Computing

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