Znyx Networks bh5700 manual High Availability Networking, Surviving Partner

Chapter 3 High Availability Networking

High availability networking is achieved by eliminating any single point of failure through redundant connectivity: Redundant cables, switches and network interfaces for hardware, combined with HA software solutions on both the hosts and switches to control the HA hardware and maintain connectivity. An HA solution called Surviving Partner is provided on the switch.

For host-side HA, the most common solution is to use the Linux bonding driver. HA solutions like the Linux bonding driver present a single, virtual interface to the protocol stack while managing multiple physical links. Figure 3.1: Host HA Architecture shows the relation of the protocol stack, a bonding driver and physical ports.

Figure 3.1: Host HA

Architecture

A failover between physical links can be made very quickly without requiring change to the IP or MAC address of the virtual interface, effectively transparent from the applications point of view. With redundant links from a switch (or switches) to the host, one link is maintained as the ACTIVE link and the other as STANDBY. If the ACTIVE link were to go down, the STANDBY becomes the new ACTIVE, while presenting the same virtual interface to the host.

NOTE: It is important that the bonding solution provide an active-backup mode. For the Linux bonding driver set “mode == 1” see the http://sourceforge.net/projects/bonding/ documentation for more information. Use the recommendations for Linux kernel 2.4x not 2.6x.

Redundant connections provide an ACTIVE and STANDBY link to a switch, or provide redundant links between more than one switch. In the case of more than one switch, a complete HA solution requires a switch-based HA solution.

Surviving Partner

Surviving Partner is a switch-based HA solution. Surviving Partner runs on the switches to provide transition of Layer 2 and Layer 3 switching functionality between two or more switches. Surviving Partner is comprised of many interactive protocols and processes including VRRP, zlmd, zlc, and others.

Ethernet Switch Blade User's Guide release 3.2.2j page 27