H3C S5810 Series, Руководство по эксплуатации

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Virtual Router Redundancy Protocol (VRRP) is designed to address this problem. VRRP adds routers
that can act as network gateways to a VRRP group, which forms a virtual router. Routers in the VRRP
group elect a master through the VRRP election mechanism to take the responsibility of a gateway, and
hosts on a LAN only need to configure the virtual router as their default network gateway.
VRRP is an error-tolerant protocol, which improves the network reliability and simplifies configurations
on hosts. Deploying VRRP on multicast and broadcast LANs such as Ethernet, you can ensure that the
system can still provide highly reliable default links without changing configurations (such as dynamic
routing protocols, route discovery protocols) when a device fails, and prevent network interruption due
to failure of a single link.
The S5810 series Switches support VRRPv2 that works in Standard protocol mode based on RFCs.
VRRPv2 is based on IPv4.
VRRP Standard Protocol Mode
Introduction to VRRP Group
VRRP combines a group of routers (including a master and multiple backups) on a LAN into a virtual
router called VRRP group.
A VRRP group has the following features:
z
A virtual router has an IP address. A host on the LAN only needs to know the IP address of the
virtual router and uses the IP address as the next hop of the default route.
z
Every host on the LAN communicates with external networks through the virtual router.
z
Routers in the VRRP group elect the master acting as the gateway according to their priorities. The
other routers function as the backups. When the master fails, to ensure that the hosts in the
network segment can communicate with the external networks uninterruptedly, the backups in the
VRRP group elect a new gateway to undertake the responsibility of the failed master.
Figure 1-2 Network diagram for VRRP
Host A
Host B
Host C
Router A
Router B
Router C
Virtual router
Network
As shown in Figure 1-2 , Router A, Router B, and Router C form a virtual router, which has its own IP
address. Hosts on the Ethernet use the virtual router as the default gateway.
The router with the highest priority of the three routers is elected as the master to act as the gateway,
and the other two are backups.