The value of pwTemplateIgmpRobustCount specifies the
value of the Robust count.
This object allows tuning for the expected packet loss on
the SDP. If an SDP is expected to be lossy, the Robustness
Variable may be increased. IGMP snooping is robust to
(Robustness Variable-1) packet losses.
The value of this object is only meaningful when the
value of pwTemplateIgmpSendQueries is 'enabled'.