Understanding Hot Standby

Hot Standby Overview

If only one FW is deployed at the egress of the network and a fault occurs on it, services on the entire network will be adversely affected. To improve network reliability, two FWs must be deployed and work in hot standby mode.

System Requirements for Hot Standby

This section describes the hardware, software, and license requirements for hot standby.

Heartbeat Link

In hot standby networking, heartbeat links are used to exchange messages between two FWs to learn about the peer status and back up configuration commands and various entries. The interfaces at both ends of a heartbeat link are called heartbeat interfaces.

Hot Standby Working Modes

This section describes the hot standby modes to help you select the right mode.

VGMP Group

VRRP Group Management Protocol (VGMP) is a Huawei proprietary protocol. The VGMP group concept is defined in the VGMP protocol. The FWs manage the active/standby status based on the VGMP group.

VRRP-based Hot Standby

When the service interfaces on the FWs work at Layer 3 and connect to a switch, you can configure Virtual Router Redundancy Protocol (VRRP) on the FWs to implement hot standby.

Hot Standby Using Dynamic Routing

When a FW service interface works at Layer 3, a dynamic routing protocol (OSPF or BGP) runs between the FW and the router to implement hot standby based on dynamic routes.

Hot Standby in Transparent Mode

This section describes the mechanism of hot standby in transparent mode.

Hot Standby in Mirroring Mode

This section describes the mechanism of hot standby in mirroring mode.

Fault Monitoring and Failover

Failover means that when one FW in a hot standby network fails, the other FW takes over services from the faulty FW. The FW monitors different fault events based on the configured trigger conditions. When a fault occurs, a failover is triggered in a timely manner to ensure service continuity.

Service Active/Standby and Configuration Active/Standby Status

This section describes the service active/standby and configuration active/standby status on FWs and their differences.

Configuration and Status Backup

To ensure smooth service switchover between the two FWs, you need to back up the configuration and status information between them.

Proactive Preemption

Proactive preemption is a mechanism that enables the original active device to switch back to the active state after recovery.