From: Lupi, Guy (Guy.Lupi@xxxxxxxxxxxxx)
Date: Wed Apr 17 2002 - 18:07:28 GMT-3
Someone will correct me if I am wrong I am sure, but I believe that even if
the filtering is ethernet to ethernet the mac address must be swapped. When
looking at an ethernet router that has dlsw configured, even the local mac
addresses that it picks up will be shown in non-canonical format. So if
your workstation has mac address 1111.1111.1111, it will appear on the local
dlsw router as 8888.8888.8888. So if filtering for a mac address that is on
an Ethernet segment, you always bitswap it when you put it in the filter.
Below is an example of what I am talking about, r2 is a dlsw router and r8
is on the Ethernet segment. R8's show interface is below, notice the mac
address, and then look at the dlsw reach information on r2. R2 has that mac
address in non canonical format.
r8#sh int e0/0
Ethernet0/0 is up, line protocol is up
Hardware is AmdP2, address is 0002.16d9.c460 (bia 0002.16d9.c460)
r2----E0----r8
r2#sh dlsw reach
DLSw Local MAC address reachability cache list
Mac Addr status Loc. port rif
0040.689b.2306 FOUND LOCAL TBridge-001 --no rif--
DLSw Remote MAC address reachability cache list
Mac Addr status Loc. peer
DLSw Local NetBIOS Name reachability cache list
NetBIOS Name status Loc. port rif
DLSw Remote NetBIOS Name reachability cache list
NetBIOS Name status Loc. peer
r2#
-----Original Message-----
From: Adam Atkinson [mailto:ghira@mistral.co.uk]
Sent: Wednesday, April 17, 2002 2:55 PM
To: CCIE Groupstudy
Subject: bitflipping in dlsw - when?
I'm feeling less than clear on _when_ I need to to bitflip the MAC
address I'm given in a dlsw-related assignment.
If the mac address is from an ethernet segment, and I'm filteing on a TR
segment, I bitflip.
Are there other situations where I'd need to do this?
-- Adam Atkinson (ghira@mistral.co.uk)
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