Znyx Networks bh5700 Manuale Utente

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.  

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.

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 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