The router ID defaults to the address specified in the system interface command. If the system interface is not configured with an IP address, the router ID inherits the last four bytes of the MAC address. The router ID can also be manually configured in the config>router router-id context. On the BGP protocol level, a BGP router ID can be defined in the config>router>bgp router-id context and is only used within BGP.
If a new router ID is configured, protocols are not automatically restarted with the new router ID. The next time a protocol is initialized, the new router ID is used. An interim period of time can occur when different protocols use different router IDs. To force the new router ID, issue the shutdown and no shutdown commands for each protocol that uses the router ID, or restart the entire router.
It is possible to configure SR OS to operate with an IPv6 only BOF and no IPv4 system interface address. When configured in this manner, the operator must explicitly define IPv4 router IDs for protocols such as OSPF and BGP because there is no mechanism to derive the router ID from an IPv6 system interface address.
To configure the router ID:
- config>router
- router-id router-id
- interface ip-int-name
- address {ip-address/mask | ip-address netmask} [broadcast {all-ones | host-ones}]The following example shows a router ID configuration:
A:ALA-4>config>router# info
#------------------------------------------
# IP Configuration
#------------------------------------------
interface "system"
address 10.10.0.4/32
exit
. . .
router-id 10.10.0.4
#------------------------------------------
A:ALA-4>config>router#