24.2. DHCP options for SIP servers

[RFC3319] specifies two DHCPv6 options that allow Session Initiation Protocol (SIP) clients to locate their outbound SIP proxy server. One option carries a list of SIP server domain names and the other carries a list of 128-bit IPv6 addresses.

The "SIP server domain name list" option can carry multiple domain names. Each domain name has a Naming Authority Pointer (NAPTR) record that differs from any other. The client tries the records in the order listed, as specified in Section 12.12.1.1, trying the next record if the previous one fails.

The option is populated with the following:

  • Option code – OPTION_SIP_SERVER_D (21).

  • Option length – variable.

  • Option data – SIP server domain name list.

The "SIP server IPv6 address list option" can carry multiple IP addresses. Servers are listed in order of preference.

The option is populated with the following:

  • Option code – OPTION_SIP_SERVER_A (22).

  • Option length – variable.

  • Option data – IPv6 addresses of SIP servers.

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