Nortel Networks WEB OS 212777 - Manual (Page 259)

Web OS 10.0 Application Guide
Chapter 11: High Availability n 259
212777-A, February 2002
Web OS Extensions to VRRP
This section describes the following VRRP enhancements that are implemented in Web OS:
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Virtual Server Routers
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Sharing/Active-Active Failover
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Tracking VRRP Router Priority
Virtual Server Routers
Web OS supports virtual server routers, which extend the benefits of VRRP to virtual server IP
addresses that are used to perform SLB.
Virtual server routers operate for virtual server IP addresses in much the same manner as Vir-
tual Interface Routers operate for IP interfaces. A master is negotiated via a bidding process,
during which information about each VRRP router’s priority is exchanged. Only the master can
process packets that are destined for the virtual server IP address and respond to ARP requests.
One difference between virtual server routers and virtual interface routers is that a virtual
server router cannot be an IP address owner. All virtual server routers are renters.
All virtual routers, whether virtual server routers or virtual interface routers, operate indepen-
dently of one another; that is, their priority assignments, advertisements, and master negotia-
tions are separate. For example, when you configure a VRRP router’s priority in a virtual
server router, you are not affecting that VRRP router’s priority in any virtual interface router or
any other virtual server router of which it is a part. However, because of the requirement that
MAC addresses be unique on a LAN, VRIDs must be unique among all virtual routers,
whether virtual interface routers or virtual server routers.