Avaya P333R-LB 사용자 설명서

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Avaya 
P333R-LB User’s Guide
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Chapter 13
Layer 3 Redundancy
This chapter discusses the redundancy schemes of VRRP, SRRP, and additional 
redundancy schemes (Real Server Group Backup and Real Server Backup).
VRRP
VRRP is an IETF protocol designed to support redundancy of routers on the LAN, 
as well as load balancing of traffic. VRRP is transparent to host stations, making it 
an ideal choice when redundancy, load balancing and ease of configuration are all 
required.
The concept underlying VRRP is that a router can backup other routers, in addition 
to performing its primary routing functions. Redundancy is achieved by 
introducing the concept of a virtual router. A virtual router is a routing entity 
associated with multiple physical routers. The routing functions of the virtual router 
are performed by one of the physical routers with which it is associated. This router 
is known as the master router.
For each virtual router, VRRP selects a master router. If the selected master router 
fails, another router is selected as master router.
In VRRP, two or more physical routers can be associated with a virtual router, thus 
achieving the extreme reliability inherent in the P333R-LB SAFER architecture.
In a VRRP environment, host stations interact with the virtual router. They are not 
aware that this router is a virtual router, and they are not affected when a new 
router takes over the role of master router. This makes VRRP fully interoperable 
with every host station.
VRRP can be activated on an interface using a single command, while allowing for 
the necessary fine-tuning of the many VRRP parameters. For a detailed description 
of VRRP, refer to VRRP standards and published literature.
Introducing a Load Balancer into the network creates a single point of failure. As a 
result, users will most likely want a backup implementation between two 
P333R-LBs.
For FWLB, the my-ip parameter of the hc-ip command can also be an associated 
IP address of a virtual router. In addition, the override addr owner parameter 
of the ip vrrp command should be used.
For AR, at least two virtual routers should be configured: one for the client vlan area 
and the other for the server vlan area. The servers should be configured with the 
VRRP IP as their default gateway. In addition, the clients should be configured with 
the VRRP IP as their default gateway. The same physical router should be the