HPE 5820X Series, Руководство по настройке

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Figure 51 SPT building in PIM-SSM
As shown in Figure 51 , Host B and Host C are multicast information receivers. They send IGMPv3
report messages to the respective DRs to express their interest in the information about the specific
multicast source S.
After receiving a report message, the DR first examines whether the group address in this message
falls into the SSM group range and does the following:
•
If the group address falls into the SSM group range, the DR sends a subscribe message for
channel subscription, hop by hop, toward the multicast source S. An (S, G) entry is created on
all routers on the path from the DR to the source. An SPT is thereby built in the network, with the
source S as its root and receivers as its leaves. This SPT is the transmission channel in
PIM-SSM.
•
If the group address does not fall into the SSM group range, the receiver-side DR sends a (*, G)
join message to the RP, and the multicast source registers with the source-side DR.
Relationship among PIM protocols
In a PIM network, PIM-DM cannot run together with PIM-SM, BIDIR-PIM, or PIM-SSM. However,
PIM-SM, BIDIR-PIM, and PIM-SSM can run together. When they run together, which one is chosen
for a receiver trying to join a group depends, as shown in
Figure 52 .
Source
Server
Host A
Host B
Host C
Receiver
Receiver
Multicast packets
SPT
Subscribe message
DR
DR
RP