c-bsr hash-length(VPN instance PIM view/PIM view of a public network instance)

Function

The c-bsr hash-length command sets a global hash mask length for candidate-bootstrap routers (C-BSRs).

The undo c-bsr hash-length command restores the default value.

By default, the global hash mask length of C-BSRs is 30.

Format

c-bsr hash-length hashLengthValue

undo c-bsr hash-length

Parameters

Parameter	Description	Value
hashLengthValue	Specifies a global hash mask length for C-BSRs.	The value is an integer ranging from 0 to 32.

Parameter

Description

Value

hashLengthValue

Specifies a global hash mask length for C-BSRs.

The value is an integer ranging from 0 to 32.

Views

VPN instance PIM view, PIM view of a public network instance

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
pim	write

Usage Guidelines

Usage Scenario

On a PIM-SM network where a rendezvous point (RP) is dynamically elected using the BSR mechanism, each candidate-rendezvous point (C-RP) sends to the BSR an Advertisement message carrying the C-RP address, range of multicast groups that the C-RP serves, and C-RP priority. Then, the BSR collects all those information and the BSR hash mask length as an RP-set, encapsulates the RP-set into a bootstrap message, and advertises the message to all Routers on the network. All Routers use the RP-set and follow the same RP election rules to elect an RP for a specific group.

The RP election rules are as follows:

The C-RP with the highest priority wins (a larger priority value indicates a lower priority).
If the C-RPs have the same priority, the hash function is started. The C-RP with the largest calculated value is elected as the RP.
If all C-RPs have the same priority and calculated hash value, the C-RP with the largest address wins the election.
To configure a global hash mask length for C-BSRs, run the c-bsr hash-length command.

Prerequisites

The multicast routing function has been enabled using the multicast routing-enable command in the public network instance view or VPN instance view.

Configuration Impact

If the c-bsr hash-length command is run more than once, the latest configuration overrides the previous one.

Example

# In the public network instance, set the global hash mask length to 16 for C-BSRs.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] pim
[*HUAWEI-pim] c-bsr hash-length 16