Failover Configuration on Audiocodes Mediant Gateway

Description:

This document describes configuration of failover on a pair of audiocodes SBCs.

The Basics:

Failover for these devices is very bare-bones. A hearbeat cable is installed either through a switch or connected directly to the pair, and when a critical event such as loss of connectivity over a particular interface or via the hearbeat cable is detected, the secondary immediately goes into standalone mode and starts talking over the primary IP and attempting to serve calls.

If the hearbeat cable is disconnected between the devices, both primary and secondary will assume it’s partner is down and both will start talking over the same primary IP, causing a variety of call related issues.

Other features regarding HA include the ability to add test IPs/pings to verify SIP circuit connectivity and initiate failover given a failure and the ability to set priority for each unit in the failover pair to prefer one as primary over the other given all is working.

High Availability Configuration:

The first steps for configuration of failover involves the configuration of the uplink/hearbeat cable between the audiocodes devices. For the purposes of this document, we will assume that the uplink will be direct and that an IP has already been configured on both devices, from which you can reach the web interface for further configuration.

1. Open up the web interface of the device and go to Configuration -> VOIP -> Network -> IP Interfaces Table.
2. Add an interface with the following values:
   1. Index: Default
   2. IApplication Type: Maintenance
   3. IInterface mode: IPV4 Manual
   4. IIP Address, I would choose a /30 network for the sake of argument let’s use 10.0.0.0/30, which means the primary would be 10.0.0.1
   5. IPrefix Length: 30
   6. IDefault gateway: 0.0.0.0
   7. IInterface Name: ‘FAILOVER’
   8. IPrimary and Secondary DNS: 0.0.0.0
   9. Underlying Device: None
3. Now go to your ‘Ethernet Groups Table’ (is in the same subtree as Configuration -> VOIP -> Network -> IP Interfaces Table) and edit the first available group, let’s say that is GROUP_2.
   1. Index: Default
   2. Group: GROUP_2
   3. Mode: 2RX 1TX
   4. Member1: GE_3
   5. Member2: GE_4
4. Now go to System->HA Settings and configure the following:
   1. HA Remote Address: 10.0.0.2
   2. HA Revertive: Enable
   3. HA Priority: 1
   4. HA Device Name: HA_PRIMARY
5. Save your configuration and power off the primary.
6. Now power up the secondary audiocodes and repeat the steps for configuring the IP interface and ethernet groups, using 10.0.0.2 for the interface IP.
7. Go to System->HA Settings and configure the following
   1. HA Remote Address: 10.0.0.1
   2. HA Revertive: Enable
   3. HA priority: 5
   4. HA Device Name: HA_SECONDARY
8. Now save your configuration and power down the audiocodes.

Establishing HA for the First Time:

The key here is patience and booting the audiocodes at the same time.

1. Connect GE_3 and GE_4 from the primary to the secondary.
2. Connect LAN interface cable (assume GE1) for the primary and secondary to their corresponding switches.
3. Start a ping test going to the primary’s external address (web interface).
4. Power on both the primary and secondary at the same time.
5. After about 2 minutes, you should see the primary’s address respond. Go ahead and login to the web interface.
6. On the main splash page, you will see the ‘High Availability’ set to standalone. Wait 60 seconds.
7. 60 seconds later, refresh your screen, you should see ‘High Availability’ change to ‘synchronizing’.
8. Wait another 60 seconds, at which point the picture of the current device should change to show the primary highlighted in green and the secondary highlighted in cornflower blue. Notice ‘High Availability’ is set to ‘Operational’. Once you see this, HA has been fully established.

mfuller, PEI