Configuring RUI in Exclusive Address Pool Mode

In BRAS multi-device backup scenarios, proper address pool configuration helps achieve efficient use of addresses.

Context

The master and backup devices are configured with address pools in shared mode. If a link fault triggers a master/backup device switchover, the backup device (the new master device) can continue to assign addresses of the original master device (the new backup device) to users through a remote DHCP server. This prevents address pool resource wastes.

Procedure

Configure address pools on the master and backup devices.
1. Run system-view
  The system view is displayed.
2. Run ip pool pool-name [ bas { local | remote } rui-slave ]
  An IPv4 address pool is configured, and its view is displayed.
  
  A local primary address pool and a local RUI-slave address pool must be configured on both the master and backup devices.
  
  A remote DHCP server can be used to allocate addresses to users logging in to the master and backup devices. If a remote DHCP server is used, you must configure a remote address pool on the master device and a remote RUI-slave address pool on the backup device. The address pools must be associated with the DHCP server group on the remote DHCP server.
3. Run gateway ip-address { mask-length | mask }
  A gateway address is configured for each address pool.
  
  The gateway address and subnet mask are used to check whether an address segment is in the same subnet as the gateway. Therefore, the gateway address and subnet mask must be configured before the address segment.
4. Run section section-number start-ip-address [ end-ip-address ]
  An address range is configured for each address pool.
  
  If both the master and backup devices have two address pools configured, the address pools on each device must use different address ranges. In addition, the primary address pool on the master device and the secondary address pool on the backup device share the same address range, so do the secondary address pool on the master device and the primary address pool on the backup device. This prevents address conflicts if a master/backup device switchover occurs in a load balancing scenario.
  
  If an RUI-slave address pool is configured using the local rui-slave parameter, you can perform the following step to associate a remote DHCP server group with the specified address pool.
  
  If an RUI-slave address pool configured using the local rui-slave parameter is bound to an RBS, the address pool automatically uses the peer IP address in the RBS as a DHCP server IP address.
  
  Before performing the following step, run the dhcp-server group group-name remote-backup-service rbs-name command in the system view to specify the name of a DHCP server group and the RBS to be associated with the DHCP server group.
5. (Optional) Run dhcp-server group group-name
  A remote DHCP server group is associated with the specified address pool.
  
  The remote DHCP server group associated with the secondary address pool on the backup device must be mapped to the master device. In a load balancing scenario, the remote DHCP server group associated with the secondary address pool on the master device must also be mapped to the backup device.
6. Run commit
  The configuration is committed.
(Optional) Configure address pool mappings in the RBP.
1. Run system-view
  The system view is displayed.
2. Run remote-backup-profile service-name
  The RBS view is displayed.
3. Run service-type bras
  The remote backup for user services is enabled.
4. Run ip-pool [ pool-group ] source-name include [ pool-group ] destination-name [ node node-id ]
  Address pool mappings in the RBP are configured.
  
  A source address pool can be mapped to multiple target address pools in ascending order by node-id, which means that the mapping starts from the target address pool with the smallest node-id.
  
  If a remote DHCP server takes precedence over a local address pool in address allocation, the secondary address pool must have a higher priority than the primary address pool. However, if a local address pool takes precedence over a remote DHCP server, the primary address pool must have a higher priority than the secondary address pool.
5. (Optional) Run frame-route metric metric-num
  The preference of a route used by the RADIUS server to deliver an IP address is configured.
  
  This step applies only to PPP private line users.
6. Run commit
  The configuration is committed.