3com 3031 Instruccion De Instalación
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MSDP C
ONFIGURATION
MSDP Overview
Multicast Source Discovery Protocol (MSDP) is used to discover multicast source
information in other PIM-SM domains. A RP configured with MSDP peers notifies
all of its MSDP peers of the active multicast source message in its domain via SA
message. In this way, multicast source information in a PIM-SM domain is
transmitted to another PIM-SM domain.
information in other PIM-SM domains. A RP configured with MSDP peers notifies
all of its MSDP peers of the active multicast source message in its domain via SA
message. In this way, multicast source information in a PIM-SM domain is
transmitted to another PIM-SM domain.
MSDP peer relationship can be established between RPs in different domains, or in
the same domain, or between a RP and a common router, or between common
routers. The connection between MSDP peers is TCP connection.
the same domain, or between a RP and a common router, or between common
routers. The connection between MSDP peers is TCP connection.
MSDP makes a PIM-SM domain independent of the RP in another PIM-SM
domain. After getting multicast source information in that domain, the receiver iin
can join directly to the SPT of the multicast source in that domain.
domain. After getting multicast source information in that domain, the receiver iin
can join directly to the SPT of the multicast source in that domain.
Another application of MSDP is Anycast RP. In a domain, configure a certain
interface (usually Loopback interface) on each router with the same IP address.;
designate these interfaces as candidate RPs and create MSDP peer relationship
among them. After the unicast route convergence, the multicast source can select
the nearest RP for registration, and the receiver can also select the nearest RP to
add into its RPT. The RPs exchange individual registration source information via
MSDP peers. Therefore, every RP knows all multicast sources of the entire domain;
and every receiver on each RP can receive multicast data from all the multicast
sources in the entire domain.
interface (usually Loopback interface) on each router with the same IP address.;
designate these interfaces as candidate RPs and create MSDP peer relationship
among them. After the unicast route convergence, the multicast source can select
the nearest RP for registration, and the receiver can also select the nearest RP to
add into its RPT. The RPs exchange individual registration source information via
MSDP peers. Therefore, every RP knows all multicast sources of the entire domain;
and every receiver on each RP can receive multicast data from all the multicast
sources in the entire domain.
By initiating registration and RPT joining to the nearest RP, MSDP implements RP
load sharing. Once a RP turns invalid, its original registered source and receivers
will select another nearest RP, implementing redundant RP backup .
load sharing. Once a RP turns invalid, its original registered source and receivers
will select another nearest RP, implementing redundant RP backup .
In addition, MSDP excludes redundant SA messages through the RPF check
mechanism, and prevents the flooding of SA messages among MSDP peers via the
Mesh Group.
mechanism, and prevents the flooding of SA messages among MSDP peers via the
Mesh Group.
MSDP Working
Principles
As shown in Figure 151, RPs in PIM-SM domain 1, domain 2 and domain 3 are in
an MSDP peer relationship, and there is a group member in domain 3. If a
multicast source in domain 1 sends data to this group in domain 3, the whole
process up to the group member in domain 3 receiving the multicast data is as
follows:
an MSDP peer relationship, and there is a group member in domain 3. If a
multicast source in domain 1 sends data to this group in domain 3, the whole
process up to the group member in domain 3 receiving the multicast data is as
follows:
1 The multicast source in PIM-SM domain 1 begins to send datagram.
2 The DR connected to the multicast source encapsulates the datagram into Register
packets and forwarrd to the RP in domain 1.
3 The RP in domain 1 decapsulates the packet and forwards it along the RPT to all
the members within the domain. The domain members can choose to take the
path along SPT.
path along SPT.