Avaya Aura® Device Services provides clients with the Presence Services or Avaya Multimedia Messaging server FQDN and port values using the ESMSRVR and ESMPORT parameters respectively. When clients receive a server FQDN, they resolve it to a single IP address and then try to connect to this address. Previously, Avaya Aura® Device Services used System Manager user profiles as the primary source for server FQDN values.
If the server FQDN resolves to multiple FQDN addresses, there might be an issue when clients resolve the FQDN and try to connect to a failed IP address, but do not try to use other IP addresses. To prevent this issue, Avaya Aura® Device Services can perform automatic DNS SRV service lookup to resolve the server FQDN and port. Avaya Aura® Device Services sets the values of ESMSRVR and ESMPORT based on the first matching record it finds during the DNS SRV query.
Avaya Aura® Device Services supports the following discovering methods for the messaging server FQDN value:
Publishing the ESMSRVR and ESMPORT values using the Dynamic Configuration service.
Obtaining the FQDN value from the System Manager user profile. This method can be enabled or disabled using the legacy ESM_MULTISITE_ENABLED parameter.
Performing DNS SRV service lookup on the FQDN that is found in the System Manager user profile. This method can be enabled using the new AUTO_AMM_LOOKUP_ENABLED parameter.
Note:
Avaya Aura® Device Services deployed in an environment without Avaya Aura® supports the first method only. Other methods are not supported.
By default, automatic DNS lookup is disabled, so Avaya Aura® Device Services uses server FQDN and port values that are configured in the System Manager user profile. If you want to resolve the server FQDN using DNS SRV lookup, you must set the AUTO_AMM_LOOKUP_ENABLED parameter to 1 using the Dynamic Configuration service.
In a migration scenario, Avaya Aura® Device Services continues to use the values configured before migration. In this case, automatic DNS lookup is enabled only if ESM_MULTISITE_ENABLED was set to 0 before migration.
The following table shows which ESMSRVR and ESMPORT values Avaya Aura® Device Services provides to clients depending on the ESM_MULTISITE_ENABLED and AUTO_AMM_LOOKUP_ENABLED values.
Dynamic Configuration parameter value |
Value Avaya Aura® Device Services provides to clients |
ESM_MULTISITE_ENABLED |
AUTO_AMM_LOOKUP_ENABLED |
ESMSRVR |
ESMPORT |
1 |
Not published. Derived value is 0 |
The value configured in the System Manager user profile. If the value is not found, then the published ESMSRVR value is used, if available. |
The ESMPORT value published using the Dynamic Configuration service is used, if available. |
0 |
Not published. Derived value is 1 |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMSRVR value is used, if available. |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMPORT value is used, if available. |
Not published. Derived value is 1 |
Not published. Derived value is 0 |
The value configured in the System Manager user profile. If the value is not found, then the published ESMSRVR value is used, if available. |
The ESMPORT value published using the Dynamic Configuration service is used, if available. |
1 |
0 |
The value configured in the System Manager user profile. If the value is not found, then the published ESMSRVR value is used, if available. |
The ESMPORT value published using the Dynamic Configuration service is used, if available. |
1 |
1 |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMSRVR value is used, if available. |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMPORT value is used, if available. |
0 |
1 |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMSRVR value is used, if available. |
The value received using the DNS SRV query. If the query fails or no result is found, then the published ESMPORT value is used, if available. |
0 |
0 |
The ESMSRVR value published using the Dynamic Configuration service is used, if available. |
The ESMPORT value published using the Dynamic Configuration service is used, if available. |
When the DNS SRV query fails, Avaya Aura® Device Services assumes that no matching DNS records were found. Avaya Aura® Device Services then uses ESMSRVR and ESMPORT values that are set according to the rules listed in the table.
