The principle introduction and application of VRRP of virtual router Redundancy protocol

VRRP Introduction:

VRRP (Virtual ROUTER redundancy PROTOCOL) is also referred to as the redundancy protocol of a dummy router. is a LAN access device backup protocol. He can dynamically assign responsibility for a virtual router to one of the VRRP routers in the local area network. The VRRP router that controls the IP address of a virtual router is called the primary router, and he is responsible for forwarding packets to these virtual IPs. Once the primary router is unavailable, the selection process provides a dynamic failover mechanism that allows the IP address of the virtual router to act as the default first-hop router for the terminal host. The advantage of using VRRP is the availability of a higher default path without the need to configure dynamic routing or Routing discovery protocols on each terminal host.

The role that the router assumes:

Active Router: The router that is responsible for forwarding packets throughout (MASTER Router) is called the active router.

Backup routers: All called (backup Router) is responsible for backing up the primary router and converting it to the active router role once the primary router fails.

The specified scenario for the role:

The HSRP protocol uses a priority scheme to determine which routers configured with the HSRP protocol become active routers. If a router's priority is set higher than all other routes, the route is an active route. When an active route is down or a single point of failure occurs, the active route is again elected in the backup route according to the priority level. The larger the number, the higher the priority.

VRRP Advantages:

The arch has a redundant network that provides load balancing and enables high availability of the network.

Three state models configured for VRRP routers

Initalize initial state, neither active nor backup state, send Hello Package

Master Active state. Forwarding Packets

Backup status, backup is used when master router is down or down, and backup becomes new master.

An important part of VRRP:

VRRP a set of routers in the LAN (parcel a master and several backup) into a virtual router called a backup group. And this virtual router has its own IP address. That is, each backup group has a virtual router.

VRRP Message Format:

VRRP only one broadcast message. The main router is issued periodically to advertise its presence, using such a message to detect various parameters of the virtual router and to elect the main router.

Practical Walkthrough:

Equipment requirements:

Quidway S2000 Exchange Equipment 2 units, ROUTER 3600 routing equipment two;

Topological structure: