All things related to multicast

[Marshall Eubanks <>]

On Jun 11, 2008, at 5:43 PM, Leonard Giuliano wrote:

> Keep in mind that SAP is useful for some apps like SDR, VLC, IPTV,  
> etc.
> Policing the entire SAP group to 1Mbps just makes it easier to DOS  
> SAP-
> now you only need to send 1Mbps of mcast data at the SAP group and  
> no good
> SAP packets will get through either, effectively taking down the  
> entire
> SAP service.
>
> Routers have no problems with high SAP data rates.  They will happily
> forward them with no problems.  The problem happens when you tell the
> routers to listen to these SAP announcements.
>
> Listening to SAP messages was once a nice, quick and easy way to see  
> if
> mcast was working.  The benefit may not be worth the risk anymore.   
> May
> want to think about simply turning off SAP listening on the routers
> (delete protocols sap / no sdr listen).

I keep thinking that after each SAP storm there won't be any more  
people with routers listening to SAP,
which sounds very archaic to me. Why does this keep coming up ? Is  
there some default router config
that needs to be changed.

Regards
Marshall


> This will still forward the SAP announcements to the intended  
> receiving
> hosts, it just won't cache these messages on the routers.
>
>
> -Lenny