Brocade BigIron RX Series Configuration Guide - Manual (Page 535)

BigIron RX Series Configuration Guide 457
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Overview of VRRP
17
FIGURE 85 Router1 and Router2 are configured as a VRRP virtual router to provide redundant
network access for Host1
With VRRP, you configure virtual routers that span across the physical routers. A virtual router acts
as a default router for hosts on a shared LAN. For example,
Figure 85 has one virtual router
configured identified as VRID1.This virtual router ID is associated with Router 1 and Router 2.
Since there are more than one IP addresses configured on Router 1 and Router 2, one of the
physical addresses is assigned to the virtual router. For example, in
Figure 85 , IP address
192.53.5.1, the IP address assigned to Router 1’s interface 1/6, is assigned as the IP address of
virtual router VRID1. Router 1 becomes the Owner of the virtual router VRID1 and is the router that
responds to packets addresses to any of the IP addresses in virtual router VRID1.
In addition, one router in the virtual router is elected as the Master router. Other routers act as
backups. The Master router is the one that forwards packets sent to the IP addresses in the virtual
router and answers ARP requests for these IP addresses. The Backup router takes over for the
Master router when the Master router fails.
NOTE
You can provide more redundancy by also configuring a second VRID with Router2 as the Owner and
Router1 as the Backup. This type of configuration is sometimes called Multigroup VRRP.
Master router election
Virtual routers use the VRRP priority values associated with each VRRP router to determine which
router becomes the Master. When you configure an Owner router, the device automatically sets the
its VRRP priority to 255, the highest VRRP priority. The router in the virtual router with the highest
priority becomes the Master. Other routers become the backup and can be assigned priorities 3 –
254. The default priority value is 100.
Internet
or
enterprise Intranet
Internet
or
enterprise Intranet
Host1
Default Gateway
192.53.5.1
192.53.5.1 e 1/6 e 1/5 192.53.5.3
e 3/2 e 2/4
VRID1
Router1 = Master
IP address = 192.53.5.1
MAC address = 00-00-5E-00-01-01
Priority = 255 VRID1
Router2 = Backup
IP address = 192.53.5.1
MAC address = 00-00-5E-00-01-01
Priority = 100
Owner
Router1 Router2