Enterasys Networks X-PeditionTM manual Icmp Ping, Interface Monitoring

IP Routing Protocols

•Master VR - all traffic, including locally generated or forwarding traffic, uses one of the virtual MAC addresses as the source MAC address except VRRP protocol packets, which use the corresponding virtual MAC address as the source MAC address. For example, if four VRs occupy one interface, two are in a master and the others a backup state. The VRRP router uses one of the virtual MAC addresses of the master VRs as the source MAC address for all traffic transferring over this interface, except VRRP protocol packets, which use the corresponding virtual MAC address as the source MAC address.

•Backup VR - all traffic will use a real physical MAC address as the source MAC address. For example, If there are two VRs on one interface and both are in the backup state. The VRRP router will use the real physical MAC address of this interface as the source MAC address for all traffic transferred over this interface.

ICMP Ping

RFC-2338 specifies that a VR master that is not the actual address owner should not respond to an ICMP ping associated with the virtual IP address. The vrrp <group> master-respond-pingcommand allows the VR master to respond to a ping regardless of actual IP address ownership.

Interface Monitoring

This feature, invoked by vrrp <group> track, allows a different router to act as the default gateway when a route through the local router is unavailable. An interface of a VR (usually the intended master of the VR) is set to monitor another interface on the same router, and will refrain from acting as the master of the VR if the monitored interface is down. It lowers its VR priority to

0 when the XSR meets one of the following conditions:

•The monitor interface does not exist. This occurs when you configure one monitor interface on a certain VR but do not create that interface.

•The monitor interface is removed. This occurs you remove one port which has been configured as the monitor port on a certain VR.

•The monitor interface fails. This occurs in the following cases:

–You change the administrate state of the interface to down.

–You remove the IP address of that interface.

–The physical layer of the interface fails due to a disconnected cable, for example.

–The link layer of the interface fails, such as a PPP or FR link.

The VR will increase its priority back to the original value, and may become the Master VR again if preemption is enabled, when the router meets all of the following conditions:

•The physical layer of the monitor interface comes up.

•The link layer of the monitor interface comes up.

•You configure a valid IP address for the monitor interface.

•You change the administrate state of the monitor interface to up.

When the monitored interface comes up again, the interface of the VR will increase its priority back to the original value, and may become the master VR again if preemption is enabled with vrrp <group> preempt. You can manually set the VR priority level with vrrp <group>

priority.

5-32 Configuring IP