Changing the Router ID

Although a Layer 3 device may have multiple IP addresses configured on different interfaces, some routing protocols need to identify the device using one IP address, the router ID.

In most configurations, a Layer 3 device has multiple IP addresses, usually configured on different interfaces. As a result, a Layer 3 device identity to other devices varies depending on the interface to which the other device is attached. Some routing protocols, including Open Shortest Path First (OSPF) and Border Gateway Protocol version 4 (BGP4), identify a Layer 3 device by just one of the IP addresses configured on the Layer 3 device, regardless of the interfaces that connect the Layer 3 devices. This IP address is the router ID.

Note: Routing Information Protocol (RIP) does not use the router ID.

By default, the router ID on a RUCKUS Layer 3 switch is one of the following:

  • If the router has loopback interfaces, the default router ID is the IP address configured on the lowest numbered loopback interface configured on the Layer 3 device. For example, if you configure loopback interfaces 1, 2, and 3 as follows, the default router ID is 10.9.9.9/24:
    • Loopback interface 1, 10.9.9.9/24
    • Loopback interface 2, 10.4.4.4/24
    • Loopback interface 3, 10.1.1.1/24
  • If the device does not have any loopback interfaces, the default router ID is the lowest numbered IP interface configured on the device.

If you prefer, you can explicitly set the router ID to any valid IP address. The IP address cannot be in use on another device in the network. RUCKUS Layer 3 devices use the same router ID for both OSPF and BGP4. If the router is already configured for OSPF, you may want to use the router ID that is already in use on the router rather than set a new one. To display the router ID, enter the show ip command at any CLI level or select IP > General links from the Configure tree in the Web Management Interface.

Note: If you change the router ID, all current BGP4 sessions are cleared.

To assign a router ID, follow these steps.

  1. Enter global configuration mode. 
    device# configure terminal
  2. Assign the router ID. 
    device(config)# ip router-id 10.157.22.26
    You can specify an IP address used for an interface on the RUCKUS Layer 3 device, but do not specify an IP address in use by another device.
  3. To verify the router ID, use the show ip command. 
    device(config)# show ip

Global Settings
ttl: 64, arp-age: 10, bootp-relay-max-hops: 4
router-id : 10.157.22.26
enabled : BGP4 UDP-Broadcast-Forwarding Source-Route Load-Sharing RARP VSRP
arp-port-move-syslog
disabled: Route-Only Directed-Broadcast-Forwarding IRDP Proxy-ARP RIP OSPF
VRRP VRRP-Extended ICMP-Redirect add-host-route-first
    The router-id in the output is set to the configured IP address.
Parent topic: IP Addressing