Configuring The Spt Switchover; Establishing The Configuration Task - Huawei Quidway S7700 Configuration Manual - Multicast

Quidway S7700 Smart Routing Switch
Configuration Guide - Multicast
----End

6.11 Configuring the SPT Switchover

A high volume of multicast data traffic increases the load of an RP, and may result in a fault.
To solve this problem, PIM-SM allows the RP or the DR at the group member side to trigger
the SPT switchover when the rate of multicast packets is high.

6.11.1 Establishing the Configuration Task

After basic functions of PIM-SM are configured, you can adjust control parameters for SPT
switchover as required.
Applicable Environment
This section describes how to configure the control parameters of the SPT switchover through
commands.
In a PIM-SM network, each multicast group corresponds to an RPT. At first, all multicast sources
encapsulate data in Register messages, and send them to the RP in the unicast mode. The RP
decapsulates the messages and forwards them along the RPT.
Forwarding multicast data by using the RPT has the following defects:
l
l
l
The solution to the preceding defects is that:
l
l
Switchs can work normally under the control of default values. The S7700 allows users to adjust
the parameters as required.
Issue 01 (2011-07-15)
instance-name | register | none } | mode { dm | sm | ssm } | flags flag-value | fsm ]
[ outgoing-interface-number [ number ] ]
– display pim [ vpn-instance vpn-instance-name | all-instance ] routing-table brief
[ group-address [ mask { group-mask-length | group-mask } ] | source-address
[ mask { source-mask-length | source-mask } ] | incoming-interface { interface-type
interface-number | register } ]
The DR at the source side and the RP need to encapsulate and decapsulate packets.
Forwarding path may not be the shortest path from the source to receivers.
Large-volume data flow increases the load of the RP, and may cause a fault.
SPT switchover triggered by the RP: The RP sends a Join message to the source, and
establishes a multicast route along the shortest path from the source to the RP. The
subsequent packets are forwarded along the path.
SPT switchover triggered by the DR at the member side: The DR at the member side checks
the forwarding rate of multicast data. If the DR finds that the rate exceeds the threshold,
the DR tiggers the SPT switchover immediately. The DR sends a Join message to the source,
and establishes a multicast route along the shortest path from the source to the DR. The
subsequent packets are forwarded along the path.
NOTE
It is recommended to adopt default values if there is no special requirement.
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
*
6 PIM-SM (IPv4) Configuration
*
183