Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH ユーザーズマニュアル
Chapter 27. Multicast Routing and Switching
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NETGEAR 8800 User Manual
Note:
This feature is supported at and above the license level listed for
this feature in the license tables in
.
Using PIM-SM, the router sends a join message to the rendezvous point (RP). The RP is a
central multicast router that is responsible for receiving and distributing the initial multicast
packets. You can configure a dynamic or static RP.
central multicast router that is responsible for receiving and distributing the initial multicast
packets. You can configure a dynamic or static RP.
When a router has a multicast packet to distribute, it encapsulates the packet in a unicast
message and sends it to the RP. The RP decapsulates the multicast packet and distributes it
among all member routers.
message and sends it to the RP. The RP decapsulates the multicast packet and distributes it
among all member routers.
When a router determines that the multicast rate has exceeded a configured threshold, that
router can send an explicit join to the originating router. When this occurs, the receiving
router gets the multicast directly from the sending router and bypasses the RP.
router can send an explicit join to the originating router. When this occurs, the receiving
router gets the multicast directly from the sending router and bypasses the RP.
Note:
You can run either PIM-DM or PIM-SM per virtual LAN (VLAN).
PIM Mode Interoperation
A NETGEAR switch can function as a PIM multicast border router (PMBR). A PMBR
integrates PIM-SM and PIM-DM traffic.
integrates PIM-SM and PIM-DM traffic.
When forwarding PIM-DM traffic into a PIM-SM network, the PMBR acts as a virtual first hop
and encapsulates the initial traffic for the RP. The PMBR forwards PIM-DM multicast packets
to the RP, which, in turn, forwards the packets to those routers that have joined the multicast
group.
and encapsulates the initial traffic for the RP. The PMBR forwards PIM-DM multicast packets
to the RP, which, in turn, forwards the packets to those routers that have joined the multicast
group.
The PMBR also forwards PIM-SM traffic to a PIM-DM network, based on the (*.*.RP) entry.
The PMBR sends a (*.*.RP) join message to the RP, and the PMBR forwards traffic from the
RP into the PIM-DM network.
The PMBR sends a (*.*.RP) join message to the RP, and the PMBR forwards traffic from the
RP into the PIM-DM network.
No commands are required to enable PIM mode interoperation. PIM mode interoperation is
automatically enabled when a dense mode interface and a sparse mode interface are
enabled on the same switch.
automatically enabled when a dense mode interface and a sparse mode interface are
enabled on the same switch.
PIM Source Specific Multicast
PIM-SM works well in many-to-many multicasting situations. For example, in video
conferencing, each participating site multicasts a stream that is sent to all the other
participating sites. However, PIM-SM is overly complex for one-to-many multicast situations,
such as multimedia content distribution or streaming stock quotes. In these and similar
applications, the listener is silent and can know the source of the multicast in advance, or can
obtain it. In these situations, there is no need to join an RP, as the join request can be made
directly towards the source.
conferencing, each participating site multicasts a stream that is sent to all the other
participating sites. However, PIM-SM is overly complex for one-to-many multicast situations,
such as multimedia content distribution or streaming stock quotes. In these and similar
applications, the listener is silent and can know the source of the multicast in advance, or can
obtain it. In these situations, there is no need to join an RP, as the join request can be made
directly towards the source.