Juniper J2300 User Manual page 498

J-series™ Services Router User Guide
Table 182: Multicast Protocol Building Blocks
Multicast Protocol
DVMRP
PIM dense mode
PIM sparse mode
PIM source-specific multicast (SSM)
IGMPv1
IGMPv2
468
Multicast Protocol Building Blocks
Description
Dense-mode-only protocol that uses
the flood-and-prune or implicit join
method to deliver traffic everywhere and
then determine where the uninterested
receivers are. DVRMP uses source-based
distribution trees in the form (S,G) and
builds its own multicast routing tables
for RPF checks.
Sends an implicit join message, so
routers use the flood-and-prune method
to deliver traffic everywhere and then
determine where the uninterested
receivers are.
PIM dense mode uses source-based
distribution trees in the form (S,G),
and also supports sparse-dense mode,
with mixed sparse and dense groups.
Both PIM modes use unicast routing
information for RPF checks.
Sends an explicit join message, so
routers determine where the interested
receivers are and send join messages
upstream to their neighbors, building
trees from receivers to a rendezvous
point (RP) router, which is the initial
source of multicast group traffic.
PIM sparse mode builds distribution
trees in the form (*,G), but migrates to
an (S,G) source-based tree if that path
is shorter than the path through the RP
router for a particular multicast group's
traffic. Both PIM modes use unicast
routing information for RPF checks.
Enhancement to PIM sparse mode that
allows a client to receive multicast traffic
directly from the source, without the
help of a rendezvous point (RP).
The original protocol defined in RFC
1112, Host Extensions for IP Multicasting.
IGMPv1 sends an explicit join message
to the router, but uses a time-out to
determine when hosts leave a group.
Defined in RFC 2236, Internet Group
Management Protocol, Version 2. Among
other features, IGMPv2 adds an explicit
leave message to the join message.
Uses
Not appropriate for large-scale Internet
use.
Most promising multicast protocol in
use for LANs.
Most promising multicast protocol in
use for WANs.
Used with IGMPv3 to create a
shortest-path tree between receiver
and source.
Used by default.