c-bsr hash-length

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 126.

Format

c-bsr hash-length hash-length

undo c-bsr hash-length

Parameters

Parameter	Description	Value
hash-length	Specifies a global hash mask length for C-BSRs.	The value is an integer ranging from 0 to 128.

Parameter

Description

Value

hash-length

Specifies a global hash mask length for C-BSRs.

The value is an integer ranging from 0 to 128.

Views

IPv6 PIM view, VPN instance IPv6 PIM view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
pim	write

Usage Guidelines

Usage Scenario

On an IPv6 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 all C-RPs have the same priority, the hash function is operated. 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 ipv6 routing-enable command in the public network instance view.

Configuration Impact

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

Precautions

A hash mask length configured for the global domain has the highest priority.

A global hash mask length configured using the c-bsr hash-length command is effective for all C-BSRs on the router. To change the hash mask length of a C-BSR on an interface, run the c-bsr command.The c-bsr command is valid only for the specified interface. The c-bsr command configuration takes precedence over the c-bsr hash-length command configuration.

Example

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

<HUAWEI> system-view
[~HUAWEI] multicast ipv6 routing-enable
[*HUAWEI] pim-ipv6
[*HUAWEI-pim6] c-bsr hash-length 16