From: Andrew Bratchell (a.bratchell@caeuk.com)
Date: Mon Oct 21 2002 - 17:45:42 GMT-3
Rick,
There is a DLSw+ design guide that is available from Cisco that is a good source of info. Certain chapters of this doc are available on the doc cd but not all. This is a good starting point.
Re less DLSw because no TR. I would not make that assumption.
In the Lab even without TR, you can still be tested on a lot of stuff. I would also look at the Ethernet redundancy feature available on 12.1 - there is a good TAC document explaining this especially when used in conjunction with switching.
Re canonical to non-cannonical conversion, it you have CCO access then you can run the bitswapping tool.
Put in the MAC address and it will do the conversion for you. The way the output is presented by the tool will show you how the conversion is done.
When you run it, you will see what I mean.
In my time I have seen two issues that come up time and again.
The first is when performing filtering on MAC address, what format should be used cannonical or non-cannonical.
Here is an extract from my study notes to explain this :-
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.
Second when you get to look at prom-peer-defaults in comparison to peer-on-demand-defaults which is used when. (If you haven't touched any of this stuff yet, don't worry, keep this section filed away somewhere)
Looking at the topology below. R1 and R2 are in peer group 5. R99 and R100 are in peer group 99.
r1--------r2--------r99-------r100
> group 5 group 99
R1 is configured as follows
dlsw local-peer peer-id 10.1.1.1 group 5 promiscuous
dlsw remote-peer 0 tcp 20.1.1.1
dlsw peer-on-demand-defaults lsap-output-list 201
dlsw prom-peer-defaults lsap-output-list 200
Question 1) If R100 forms a peer connection with R1, which lsap-output-list is applied ?
Answer 1) 201, reason - because R100 is going through border peer r99 in group 99, then R2 as the border peer in group five to reach r1. The list will be applied oubound from R1.
Question 2 - If R66 (not shown in the topology) has a remote peer connection to R1, which lsap-output-list is applied ?
Answer 2 - 200, reason because we are not using border peers here, the peer-on-demand defaults does not apply. Because R1 is configured as promiscous, it will accept the peer connection from R66 and apply the filter outbound.
If you want to test DLSw, then there are two areas to look at. First testing on NETBIOS traffic can be achieved to hooking up a couple of win95/98 PC'S configured for NETBIOS. Testing SNA is a bit more tricky, but can be done by defining static SNA Hosts (Mainframe) and Terminals (endstations). You can do this within Cisco routers using the DSPU command. It is important to note that you will need two routers which are not acting as DLSW routers, one to act as the Host , the other to act as the Terminal.
Here we have R1, acting as the terminal and R4 acting as the mainframe. In the sample configure we are sending SAP traffic with LSAP and DSAP values of 4, 8, and 12. This will give use three circuits
R1
dspu host R4SAP4 xid-snd 01712358 rmac 4000.4444.4444 rsap 4 lsap 4
dspu host R4SAP12 xid-snd 01712360 rmac 4000.4444.4444 rsap 12 lsap 12
dspu host R4SAP8 xid-snd 01712359 rmac 4000.4444.4444 rsap 8 lsap 8
!
interface Ethernet0/0
mac-address 4000.1111.1111
ip address 100.1.1.1 255.255.255.0
dspu enable-host lsap 4
dspu enable-host lsap 8
dspu enable-host lsap 12
dspu start R4SAP4
dspu start R4SAP12
dspu start R4SAP8
R4
dspu pu R1SAP4 rmac 4000.1111.1111 rsap 4 lsap 4
dspu pu R1SAP12 rmac 4000.1111.1111 rsap 12 lsap 12
dspu pu R1SAP8 rmac 4000.1111.1111 rsap 8 lsap 8
!
interface Ethernet0
mac-address 4000.4444.4444
ip address 4.1.1.1 255.255.255.0
dspu enable-pu lsap 4
dspu enable-pu lsap 8
dspu enable-pu lsap 12
dspu start R1SAP4
dspu start R1SAP12
dspu start R1SAP8
Once you have SNA traffic going across your DLSW peers your circuits will be up and you can start messing around with filtering.
Finally I would advise getting a good grasp of LLC. Radia Perlman's Router's switches and Interconnections is a good text on the subject.
Hope that is enough to get you started.
Final advise, listen to what people say, but know something works because you have tested it yourself in a lab. What I have told you is my understanding and I have tried to be as correct as possible, but see for yourself.
Good luck with your DLSw study.
Thanks
Andy
-----Original Message-----
From: Rick [mailto:ccie_2003@hotmail.com]
Sent: 21 October 2002 17:05
To: Ccielab (E-mail)
Subject: Need some help working with MAC address and Canonical/
noncanical formating
Could someone please provide some examples of how to convert an ethernet
canonical Mac to a noncanical DLSW address? I just started studying DLSW and
this is the first major issue I'm having. I'm sure this is just the begining.
On another note, DLSW should be really lite on the CCIE lab with Token Ring
going away (yea!!!! :) Does anyone have any great DLSW notes as pertains to
the new test? (or just good DLSW notes in general?)
Thanks,
Rick
************These are great notes from other GroupStudy posts...
You should know this rule:
DLSw+ always sends data in non-canonical format .
So if you have in your exam the following:
you have a router with ethernet interface - R1- and he asked you to
tell remote peers that station with mac Address X is reachable.
so before putting the mac address in ' dlsw icanreach mac-addr ' command
you should convert this MAC address into non-canonical [ because he gave you
a MAC address of ethernet station, i.e. in canonical format ].
Also in case you want to apply a MAC address to dlsw remote-peer command
you should convert the canonical MAC adress given to you to non-canonical
before applying it in the MAC access-list using the keyword "dmac-out"
in the dlsw remote-peer command.
Hope that clarifies your questions and any confusion .
I'm sure a lot of you know this already but I think it's worth saying. I
figured this out after my NMC class. If you remember the following you never
have to do binary conversion for canonical to non-canonical. Just draw the
chart before doing any conversion. I even find I can do the conversion in my
head now.
0 6 9 F Map to them selves
-------------------
1 8 map to each other
2 4 map to each other
3 C map to each other
-------------------
5 A map to each other
7 E map to each other
B D map to each other
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