Interface connections for an Avaya SBC HA pair

Last Updated : Dec 16, 2024 |

The following interface connections are required before deploying an Avaya SBC HA pair.

Interface

Description

EMS

M1 interface or management IP

EMS uses this IP to:

  • Communicate with the Avaya SBC devices.

  • Send the database to the Avaya SBC devices.

  • Check the status of the Avaya SBC devices.

  • Communicate with the NTP and DNS.

Note:

M1 interface does not support IPv6 address.

Avaya SBC

M1 interface or management IP

Avaya SBC devices use this IP to:

  • Communicate with EMS and access the server box through SSH port 22 for maintenance.

  • Communicate with NTP, most likely on the same subnet as EMS M1.

    Note:

    If the Avaya SBC M1 IP is not on the same subnet as EMS M1 IP, the Avaya SBC IP must be routable to the EMS M1 IP.

Note:

M1 interface IP does not support IPv6 address.

A1 internal interface towards PBX

This IP cannot be on the same subnet as the PBX or media board IPs or the M1 IP.

B1 external interface towards trunk or remote users

This IP cannot be on the same subnet as the M1 IP.

M2 connection

This interface is a layer 2 connection between the two Avaya SBC devices. This interface does not require an IP.

In an HA pair deployment, primary and secondary Avaya SBC instances use a Keep alive mechanism to check call processing module availability for the other Avaya SBC. This mechanism is controlled by two parameters:

  • Keep alive interval: The duration between two Keep Alive requests.

  • Max retries: The number of Keep Alive requests sent before declaring that other Avaya SBC instance’s call processing module is unavailable.

Secondary Avaya SBC sends a Keep Alive request packet after Keep alive interval is expired. If a response is not received after the Max Retries value, secondary Avaya SBC takes over as primary Avaya SBC.

For example, if Keep alive interval is set to 1500 and Max Retries is set to 3 and secondary Avaya SBC has not received a Keep Alive response for (3 x 1500 milliseconds), secondary Avaya SBC takes over as primary Avaya SBC.

You can change this value on the EMS web interface from Network & Flows > Advanced Options > HA pairs. For more information, see the “HA Pairs” section in Advanced Options field descriptions.

If frequent failovers are seen in delay prone deployed platforms such as VMWare, these numbers can be adjusted to increase the detection time to prevent frequent failovers.

Important:

The A1 and B1 IP addresses are shared between the two Avaya SBC devices. These IPs must be capable of routing and being handled at both sites. The IPs are swapped between the Avaya SBC devices using a gratuitous ARP (GARP) request that is handled by a switch or router. The GARP request indicates the MAC of the new Primary Avaya SBC interface that will now handle the IPs that were being handled by the new Secondary Avaya SBC.

All interfaces on the switches and routers to which the Avaya SBC devices and EMS are plugged in must be set as auto/auto.