All things related to multicast

[Beau Williamson <>]

At 07:17 AM 12/6/1999, Greg Shepherd wrote:
>> Also, are you using these in 'sa-filter' lists or 'sa redistribute' lists 
>or both?
>
>I currently have confi'd this for 'sa-filter'. Can you explain the
>difference?
>

The 'ip msdp redistribute' command is used to control sa messages that are 
originated by a router.  (BTW, I think the command syntax "stinks".  The term 
"redistribute" has other meanings that is inconsistant with what this command 
does. It should be something more obvious like 'ip msdp sa-originate-filter' 
since that is what it controls.  Opps. Sorry, I got off on one of my pet 
rants, IOS commands that don't say what they mean such as 'ip dvmrp 
unicast-routing'!  Why would anyone want to route their unicast traffic using 
dvmrp!  This is a ridiculous syntax which most customers don't understand and 
just causes.... [Slap! Slap!] Oh, sorry.  I'm better now.  Really, I am.  
Back to the original topic. :) )

If you are applying the access-list to ALL MSDP peers via an 'sa-filter out' 
then you accomplish the same thing in one swelled foop.  :)  However, I would 
think that you would normally want to use the same access-list in the 'ip 
msdp redistribute' command so you don't originate SA messages for RFC1918 
sources that happen to be in your own network.  

I have encountered at least one customer that needs to do this since they use 
NAT internally as well as ip multicast.  I'm sure there are others (or will 
be others) that fall into this category.

Beau