The c-bsr group command configures the Candidate-BootStrap Router (C-BSR) of the BootStrap router (BSR) administrative scope to which a specified multicast group corresponds.
The undo c-bsr group command restores the default configuration.
c-bsr group group-address { mask | mask-length } [ hash-length hash-length | priority priority ] *
undo c-bsr group group-address
| Parameter | Description | Value |
|---|---|---|
| group-address | Indicates a multicast group address in dotted decimal notation. | The value is in dotted decimal notation that ranges from 239.0.0.0 to 239.255.255.255. |
| mask | Indicates the mask of a multicast group address in dotted decimal notation. | The value is in dotted decimal notation. |
| mask-length | Indicates the mask length of a multicast address. | The value is an integer that ranges from 8 to 32. |
| hash-length hash-length | Specifies the hash mask length for the C-BSR in the BSR administrative scope to which a multicast group corresponds. | The value is an integer that ranges from 0 to 32. By default, it is 30. |
| priority priority | Specifies the priority of the C-BSR in the BSR administrative scope to which a multicast group corresponds. The greater the value is, the higher the priority of the C-BSR is. | The value is an integer that ranges from 0 to 255. By default, it is zero. |
By default, the C-BSR of the BSR administrative scope is not configured.
Usage Scenario
By default, each PIM-SM domain has only one BSR and the BSR serves all the devices in the entire PIM-SM domain. To achieve more effective management, you can divide a PIM-SM domain into multiple BSR administrative domains and a global domain. This can reduce the workload of a single BSR and designate a private-network group address for users in a specific domain.
Each BSR administrative domain maintains one BSR that serves multicast groups on network segment 239.0.0.0/8. Multicast packets for groups on this network segment cannot pass through the border of the BSR administrative domain. Multicast groups that do not belong to any BSR administrative domain belong to a global domain. The global domain maintains a BSR, serving all the remained multicast groups, namely, multicast groups beyond the range 239.0.0.0/8.
A BSR administrative domain is similar to a VPN in unicast and multicast address segment 239.0.0.0/8 equals unicast address segment 10.0.0.0/8. Other multicast group addresses can be used on the public network and address conflicts need be avoided. If a PIM-SM domain is divided into different BSR administrative domains, each BSR administrative domain equals a VPN, serving multicast groups on network segment 239.0.0.0/8, You can use the same multicast group address in different BSR administration domains.
Configuration Impact
If the c-bsr group command is run several times, the latest configuration overrides the previous one.
After the undo pim command or the undo multicast routing-enable command is run, the C-BSRs in the BSR administrative domain are automatically disabled.
Precautions
Each BSR administrative domain corresponds to a multicast group address range. Multicast packets carrying group addresses within a specified range can be transmitted only in the corresponding BSR administrative domain.