HP-UX C SIP Stack Programmer's Guide (Novembery 2007)

330 HP-UX C SIP Stack Programmer’s Guide
Introduction
 A list of domain suffixes—tells the SIP Stack which domain
suffixes should be appended to FQDNs. (For example,
“hp.com” is the suffix for the “host1.hp.com” host.)
Using suffixes allows using a short version of a name that is
within the suffix domain.
The SIP Stack supports three ways of obtaining the information that is required.
The information can be provided using the RvSipStackCfg configuration
structure when initializing the SIP Stack. For more information, see
RVSipStackCfg Configuration Structure of the Configuration chapter.
If no data (or partial data) is located in the configuration structure when the
SIP Stack initializes, the SIP Stack will try to obtain the data from the operating
system.
A third way is to provide (or change) that data during runtime. You can use the
RvSipResolverMgrSetDnsServers() and the
RvSipResolverMgrSetDnsDomains() functions to set the DNS servers and the
list of DNS suffixes during runtime.
DNS/SRV TREE RFC 3263 specifies the usage of three DNS record types:
 NAPTR—used to determine the transport for a specific domain.
 SRV—used to determine the port and transport of a specific SIP
service.
 A (or AAAA for IPv6)—used to determine the IP/IPv6 address
of a specific host.
The combination of the three types of records spans a tree, as illustrated in
Figure 15-1. Each NAPTR query can result in several SRV records. An SRV
query can result in several host records, each with several IP addresses (A/
AAAA records).