RE: DLSW and mac addresses

From: Andrew Bratchell (a.bratchell@caeuk.com)
Date: Mon Oct 14 2002 - 17:31:38 GMT-3

From my DLSW study notes

Traffic that originates on Ethernet is picked up from the local Ethernet bridge group and transported across the DLSw+ network. DLSw+ always transfers data in noncanonical format. DLSw+ will automatically make the correct MAC address conversion depending on the destination media. When DLSw+ receives a MAC address from an Ethernet-attached device, it assumes it is canonical and converts it to noncanonical format for transport to the remote peer. At the remote peer, the address is either passed unchanged to Token Ring-attached end systems or converted back to canonical format if the destination media is Ethernet.

Also be aware that when filtering with DLSw+ on Mac addresses DLSw+ works in non-canonical format (Token-Ring format). Thus, you always need to put mac addresses in this format. If you are using access-lists to specify mac output list on a DLSw+ statement, you will always use non-canonical format. If the access-list will be using to filter on a token-ring interface it will be non-canonical. If the access-list will be used to filter on an Ethernet interface it will be canonical. Make sure you know how to convert between non-cononical and canonical format. As an aid, you can use Cisco's Bitswapping tool which can be found on their web site.

Hope this helps

Thanks
Andy
-----Original Message-----
From: Rossow, Travis L [mailto:RossowTL@corning.com]
Sent: 14 October 2002 21:09
To: 'ccielab@groupstudy.com'
Subject: RE: DLSW and mac addresses

If the MAC address you want to advertise is on an Ethernet segment, I believe you need to do the conversion (from canonical to non).
If the MAC address you want to advertise is on a Token Ring segment, then you wouldn't need to make the conversion.
TLR

-----Original Message-----
From: Pieter Jordaan [mailto:pieterj@is.co.za]
Sent: Monday, October 14, 2002 1:15 AM
To: 'ccielab@groupstudy.com'
Subject: RE: DLSW and mac addresses

The address you have to use for your icanreach statement must be added in
non-canonical format.

What I would like to know is this, If you are just given a mac address to
use, how would you know which format it's in. IE: the question may state...
Users must be able to reach the following mac aaaa.bbbb.cccc. How will I
know if I have to convert the mac or use it as is.

None of the sample labs I have done to date even hint to the possibility
that I should be converting the mac before I add the ican-reach statement,

TIA

-----Original Message-----
From: Justin Cook [mailto:Justin.Cook@computerland.co.nz]
Sent: 10 October 2002 10:14 PM
To: 'ccielab@groupstudy.com'
Subject: DLSW and mac addresses

I have seen a lot of conflicted labs and posts about mac addresses and DLSW.
Can anyone clarify the following
 
- DLSW always using noncananical addresses (Tok to Tok, Eth to Eth
and Tok to Eth)? This means if asked to set a icanreach macaddress you
always convert to noncanonical before typing it in?
 
Thanks in advance
 
  

--
Justin Cook

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