Introduction to the practical application of HSRP Routing Technology in Networks

The router technology in China has developed very rapidly. So I studied the application of HSRP routing technology in the network. I would like to share with you here, hoping it will be useful to you. Vro is the core and heart of the entire network. If the router technology suffers a fatal fault, it will paralyze the local network. If it is a backbone router, the impact scope will be greater, the loss is hard to estimate. Therefore, using hot backup for router technology is an inevitable choice to improve network reliability.

1. HSRP protocol Overview

The condition for implementing HSRP is that there are multiple routers in the system and they form a "hot backup group", which forms a virtual router. At any time, only one vro in A group is active and forwards data packets. If the active vro technology fails, a backup vro technology is used to replace the active vro, however, in the view of hosts in the network, the virtual router has not changed. As a result, the host still maintains the connection and is not affected by the fault. This effectively solves the problem of router technical switching.

To reduce network data traffic, only the active router technology and the backup router technology regularly send HSRP packets after Active Routers and backup routers are configured. If the active router fails, the backup router takes over as the active router. If the backup router fails or becomes an active router, another router is selected as the backup router. In a Specific Lan, multiple hot backup groups may coexist or overlap. Each hot backup group imitates a virtual router, which has a Well-known-MAC address and an IP address. The IP address, the interface address of the vro in the group, and the host are in the same subnet, but cannot be the same. When multiple hot backup groups exist on a LAN, distributing hosts to different hot backup groups can share the load.

Ii. How HSRP works

The HSRP protocol uses a priority scheme to determine which router technology configured with the HSRP Protocol becomes the default active router. If a router technology has a higher priority than all other routers, the router becomes an active router. The default priority of vro technology is 100. Therefore, if only one vro technology has a higher priority than 100, the vro。 will become an active vro. HSRP priority is broadcast between routers with HSRP protocol set. The current active router is selected by HSRP protocol. When the active router cannot send hello messages within a preset period of time, the Standby Router with the highest priority becomes the active router. Packet transmission between routers is transparent to all hosts on the network.

Vrouters configured with the HSRP protocol exchange the following three multicast messages:
Hello --- the hello Message notifies other routers of their HSRP priority and status information. The HSRP router sends a hello message every three seconds by default;
Coup --- send a coup message when a Standby Router changes to an active router;
Resign-when the active router is down or a router with a higher priority sends a hello message, the active router sends a resign message. At any time, the router with HSRP protocol configured will be in one of the following six States:
Initial --- the status of HSRP when it is started. HSRP is not running yet. It is usually entered when the configuration is changed or the port is just started.
Learn --- the vro has obtained a virtual IP address, but it is neither an active router nor a waiting router. It monitors the HELLO messages sent from the active router and waiting for the router.
Listen --- the router is listening for hello messages.
Speak-in this status, the vro regularly sends HELLO messages and actively participates in the active vro or waits for the election of the vro.
Standby --- when the active router fails, the router is ready to take over the packet transmission function.
Active --- the Router performs the packet transmission function.

Iii. Features of this solution

1. high reliability: HSRP Hot Backup Redundancy protocol is used between two router technologies to ensure that any one of the two routers is down or the wide area network port of the router is down, will be quickly switched to another. If there are problems with both lines, use the routing policy to stop the postal subnet service and enable the dialing line.

2. effective implementation of load balancing, In the STAR-S1924F + division of their respective VLAN, the savings subnet VLAN on the left side of the router HSRP priority is higher, the default use of the FR network line; the HSRP of the subnet VLAN on the right router has a higher priority. By default, the China Unicom FR line is used. Fully utilizes Bandwidth Resources and achieves load balancing.

3. the multi-Ethernet router technology is fully used to divide the functions of multiple service network segments. Only the multi-Ethernet router in the HSRP application can achieve load balancing between the two routers, this is a great advantage of four Ethernet router interfaces.

4. Enable the QoS policy on the right-side router technology. The VoIP service requires a low latency, so the VoIP service is set to a high priority.

5. By setting VLANs on the vswitch, the security between the two subnets is effectively controlled.

6. There is no single point of failure.