[c-nsp] Unwanted multicast traffic

Thu Jul 13 07:04:40 EDT 2006

There are 3 cat 3560 with PIM-SM connected as

  R1====vlan999====R2=====vla999=====R3
   ^				   ^
    |				   |
multicast			multicast
source			receiver

on R3 only gi0/1 is up (connection to R2), all other ports is down.

but on R3 (via mrtg graph) I see multicast traffic from R1 to R2, why?

as far as i enter on R3
int vlan999
no ip pim sparse-mod

R2 stop send multicast traffic to R3

why R3 "subscribes" to unwanted multicast traffic?