Hot Backup Routing protocol: Introduction to HSRP protocol

"HSRP": Cisco Private protocol

Name: Hot Backup Routing protocol

Role: Gateway redundancy, a group with an active router,

Multiple hot spare groups can be configured when load sharing is implemented

"Configure HSRP Method"

Active End General Configuration 4 command: Join group, priority, preemptive power, port tracking

Backup-side General Configuration 2 command: Join group, preemptive right

Principle of hot Standby routing protocol

(1) Related concepts of HSRP

1, HSRP overview

HSRP (Hot Standby Routing Protocol, heat Backup routing protocol) is a proprietary technology of Cisco, it is true that when the network edge device or access link failure, user communication can quickly and transparently recover, to some of the IP network to provide redundancy

The Hot Backup routing protocol provides fault tolerance and enhanced routing for IP networks. By using the same virtual IP address and virtual MAC address, two or more routers on a LAN segment can serve as a virtual router for external service

"Routers in the HSRP group monitor each other's running state"

Members of a virtual router group constantly Exchange status information through HSRP messages

If one of the units fails, the other can take over and continue the routing function.

2. Members of HSRP Group

Active Router: Forwards packets sent to the virtual router. Active routers send hello messages to

To assume and maintain its active role

Backup Router: Monitors the running state of the HSRP group, which quickly acts as the forwarding packet when the active router is not running. The backup router also transmits the Hello message, informing the group that all

Role and status changes for router backup routers

Virtual routers: Provides an end user with a router that can work continuously. The virtual router is equipped with its own IP address and MAC address, but does not actually forward the packet

HSRP backup groups can contain other routers that monitor the hello message but do not answer

"Attention":

By default (the same priority), the router with the largest IP address becomes the new backup router, although multiple routers can be in one HSRP group, but only active routers are responsible for forwarding packets sent to the virtual router

3, HSRP principle

Each router in the HSRP group has a specified priority (Priority) to measure the priority of the router in the active router

Default priority ' 100 ', optional range ' 0~255 '