Looking at my Netware configuration, and the MTU issues I was having, I was right to think that it used to work with serial links with an MTU of 1500 along with stacker compression.  No doubt with the world moving away from traditional HDLC links, and Novell Netware, the code is in 12.4, but it doesn’t work.

Luckily someone sent me 11.3 for the 2600.

Cisco Internetwork Operating System Software
IOS ™ C2600 Software (C2600-D-M), Version 11.3(6)T, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-1998 by cisco Systems, Inc.
Compiled Tue 06-Oct-98 18:07 by ccai

It’s still strange to think of 1998 being old.  Or legacy.  But back then I had an IOS 9 device running as a terminal server, and whole lot of 2500’s & 4000’s running 10.3, and some 7000’s with 11.0.  Good times for sure!

Since I setup a simple IPX network the router config’s are pretty simple.  I didn’t even bother with TCP/IP.

R12

ipx routing c809.1dfc.0000
!
interface Ethernet0/0
no ip address
ipx encapsulation SAP
ipx network CAB2
!
interface Serial0/0
no ip address
bandwidth 1966080
ipx network BEEF
clockrate 2000000
compress stac

R13

ipx routing c808.1dfc.0000
!
interface Ethernet0/0
no ip address
ipx encapsulation SAP
ipx network CAB3
!
interface Serial0/0
no ip address
bandwidth 1966080
ipx network BEEF
clockrate 2000000
compress stac

As you can see the configuration is pretty bare bones.  But the only thing I’m interested in is compressing that serial link.  I didn’t have to do any MTU sizing games, instead logging into the server ‘just worked’.  Then I turned on the compression, and copied the server’s system folder to the local disk.

And you can see I’m getting about 1.5:1 .  Not bad for a simple setting change.

Serial0/0
Software compression enabled
uncompressed bytes xmt/rcv 8733770/81026
1 min avg ratio xmt/rcv 1.577/1.121
5 min avg ratio xmt/rcv 1.578/1.070
10 min avg ratio xmt/rcv 1.606/1.083
no bufs xmt 0 no bufs rcv 0
resyncs 0
Additional Stacker Stats:
Transmit bytes: Uncompressed = 279855 Compressed = 5124744
Received bytes: Compressed = 72387 Uncompressed = 0

But naturally dynamips is slow for doing what it does.  And to know that I’m not totally crazy, as this stuff did work before.  This should also serve as a warning to people new at the fun world of cisco, just because you have a ‘newer’ version of IOS doesn’t mean that feature XYZ is going to work correctly.  Oh sure the statements may work, but when it comes down to it, it may not work at all, or poorly.  In case you ever wondered why people hoarde IOS versions this would be why.