HP 3500YL - Manual (Page 109)

PIM-SM (Sparse Mode)
Feature Overview
and group members are sparsely distributed over a wide area can result in
unnecessary multicast traffic on routers outside the distribution paths needed
for traffic between a given multicast source and the hosts belonging to the
multicast group. In such networks, PIM-SM can be used to reduce the effect
of multicast traffic flows in network areas where they are not needed. And
because PIM-SM does not automatically flood traffic, it is a logical choice in
lower bandwidth situations.
In the 3500yl and 5400zl switches, PIM-SM is included with the Premium
License. In the 6200yl and 8200zl switches, this feature is included with the
base feature set. L i c e n s e
R e q u i r e m e n t s
Feature Overview
PIM-SM on the routers covered by this manual includes:
■ Routing Protocol Support: PIM uses whichever IP unicast routing
protocol is running on the router. These can include:
• RIP
• OSPF
• static routes
• directly connected interfaces
■ VLAN Interface Support: Up to 127 outbound VLANs (and 1 inbound
VLAN) are supported in the multicast routing table (MRT) at any given
time. This means the sum of all outbound VLANs across all current flows
on a router may not exceed 127. (A single flow may span one inbound
VLAN and up to 127 outbound VLANs, depending on the VLAN member­
ships of the hosts actively belonging to the flow.)
■ Flow Capacity: Up to 2048 flows are supported in hardware across a
maximum of 128 VLANs. (A flow is composed of an IP source address and
an IP multicast group address, regardless of the number of active hosts
belonging to the multicast group at any given time.)
■ Multicast Group to Rendezvous Point (RP) Mapping: PIM-SM uses
the Bootstrap Router (BSR) protocol to automatically resolve multicast
group addresses to Candidate-RP routers. In the current software release,
a router administers BSR operation on a PIM-SM domain basis. (BSR
zones and PIM border router operation are not currently supported by the
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