In an Avaya IX™ Messaging (now Avaya Aura® Messaging) High Availability (HA) deployment, each Voice Server Node (VSN) is engineered with specific capacity limits to ensure system stability and performance. According to official Avaya technical specifications, a single VSN is designed to support a maximum of 100 SIP ports. This limit is a fundamental design parameter for the VSN component, regardless of whether it is in a standalone or HA configuration. Exceeding this limit can lead to performance degradation and is not a supported configuration.

B. 120: This number exceeds the documented maximum capacity of 100 SIP ports for a single VSN.

C. 150: This value is 50% higher than the specified maximum and would overload the VSN's processing capabilities.

D. 220: This is more than double the supported SIP port limit and is not a valid capacity for a VSN.

1. Avaya Aura® Messaging Documentation Library, "Implementing Avaya Aura® Messaging," Release 10.8, NN43001-615, Issue 1.0, December 2020.

Page 16, Chapter 2: System capacities, Table 2: Avaya Aura® Messaging system capacities. The table explicitly states, "Maximum number of SIP ports per VSN" is "100". This document is the primary implementation guide for the system, which includes the former Avaya IX™ Messaging branding.