Communication Manager NAT Shuffling feature

Last Updated : Jul 20, 2023 |

With the Communication Manager NAT Shuffling feature, IP telephones and IP Softphones can work behind a NAT device. This feature was available before release 1.3, but it did not work with shuffled calls activated by enabling Direct IP-IP Audio. The NAT feature now works with shuffled calls.

Terms

The following terms are used to describe the NAT Shuffling feature:

  • Native Address: The original IP address configured on the device, also known as the internal address.

  • Translated Address: The IP address after it has gone through NAT, as seen by devices on the other side of the translation, also known as external address.

  • Gatekeeper: The Avaya device that is handling call signaling which is processor Ethernet.

  • Gateway: The Avaya device that is handling media conversion between TDM and IP. The device can be any of the following branch gateways:

    • G450

    • G430

With this feature, Communication Manager keeps track of the native and translated IP addresses for every IP station such as an IP telephone or IP Softphone. If an IP station registration displays with different addresses in the IP header and the RAS message, the call server stores the two addresses. The call server also alerts the station that NAT occurred.

This feature works with static 1-to-1 NAT. This feature does not work with NAPT, so the TCP/UDP ports sourced by the IP stations must not be changed. Consequently, this feature does not work with many-to-1 NAT. This feature works with many-to-a-pool NAT if the translated address of a station remains constant for when the station is registered, without port translation.

The NAT device must perform plain NAT, not H.323-aware NAT. Any H.323-aware feature in the NAT device must be disabled, so that two independent devices do not try to compensate for H.323 simultaneously.

Rules

The following rules govern the NAT Shuffling feature:

  • When Direct IP-IP Audio is enabled and a station with NAT and a station without NAT communicate, the translated address is used. The Direct IP-IP Audio parameters are configured on the SAT ip-network-region screen. Direct IP-IP Audio is enabled by default.

  • When two stations with NAT communicate, the native addresses are used when Direct IP-IP Audio is administered with Yes or Native (NAT). The translated addresses are used when Translated (NAT) is specified.

  • The Gatekeeper and Gateway must not be enabled for NAT so that these devices can be assigned to any network region.