[c-nsp] FWSM Is there a way to enable unknown unicast flooding?

[Jeff Fitzwater]

FWSM running 3.2

I am setting it up in transparent mode with 3 bridge-groups, one for 
each ISP on outside.

    The problem is each of our ISP connections are /30 netblocks and 
each bridge-group require an IP address so that it can resolve what port 
the EtherDst is on according to the Bridge Table.  If the EtherDst is 
not in Bridge Table then the FWSM will ARP for the device so it will get 
added to table, using the IP of the Bridge-group as Src.  This is only 
because the FWSM will never flood unicast packets if it does not have a 
bridge-table entry, but if flooding could be enabled in our case, (only 
two routers on link) then I would not have to assign each bridge-group 
an IP, and just use one for management.

    I have demonstrated in our lab that this is the way it work and 
CISCO concurs. 
It is true that the likelihood of it needing to ARP is very slim but 
there is the possibility.

    If there were only a hidden switch to enable flooding for our case.

    We have one ISP which may not allow the use of a /29 link.

   

Any thoughts on this issue.



Thank you for any help;



Jeff Fitzwater
OIT Network Systems
Princeton Univeristy