From: StudyManiac (groupstudy1@xxxxxxxx)
Date: Wed Feb 13 2002 - 17:33:52 GMT-3
The command to disable IPX routing and enable FFFFFFFE as a valid network is
'no ipx default-route'.
As far as he NLSP junk, this is slightly OT, but are you ready to hurt your
head? Read on:
The -1 (FFFFFFFF) and -2 (FFFFFFFE) in IPX mean 'all routes' and 'default
route'. The numbers are negative binary numbers, and as weird as it sounds,
here's how it works.
To change the sign of a binary number, you do what's called a "two's
complement" of the number. The "one's complement" of a number is found by
simply flipping the bits (changing the ones to zeros and the zeros to ones).
The "two's complement" is the one's complement plus 1. For these examples
we'll work in 32 bits, like an IPX network number.
Let's take the decimal number 1 (0x00000001) and write it as a 32 bit binary
number:
1 = 00000000000000000000000000000001
The one's complement is 11111111111111111111111111111110, and after adding 1
you arrive at the two's complement of 11111111111111111111111111111111, or
0xFFFFFFFF, which, by this definition, is -1. (Incidentally, this is why 1
can be used to represent all IPX networks in an access-list.)
Now let's take the decimal number 2 (0x00000002) and write it as a 32 bit
binary number:
2 = 00000000000000000000000000000010
The one's complement is 11111111111111111111111111111101, and after adding 1
you arrive at the two's complement of 11111111111111111111111111111110, or
0xFFFFFFFE, which, by this definition, is -2. (This represents the default
route in IPX)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
RSiddappa@NECBNS.com
Sent: Wednesday, February 13, 2002 3:05 AM
To: ericlemmons@yahoo.com; ccielab@groupstudy.com
Subject: RE: IPX network number clarification
no IPX default network
I am not sure about the NLSP part.
Some one comment.
R.
-----Original Message-----
From: Eric Lemmons [mailto:ericlemmons@yahoo.com]
Sent: Tuesday, February 12, 2002 8:06 PM
To: ccielab@groupstudy.com
Cc: ccielab@groupstudy.com
Subject: IPX network number clarification
IPX network numbers were originally valid from 1 to FFFFFFFE.
When NLSP came along, the FFFFFFFE network number was taken to
indicate the network that was advertising the default route.
Some documentation indicates that you can use the FFFFFFFE network
number, other documentation says you can't.
Can someone explain how this special default route network number,
FFFFFFFE, is implemented?
And is it possible to turn it off?
Is it only needed when IPX NLSP is being used?
Thanks!
Eric
=====
(James) Eric Lemmons
Home: 972-862-6581
Work: 469-255-1843
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