Internet protocol address selection in session initiation protocol communications
Examples disclosed herein provide methods and systems for selecting Internet Protocol addresses for Session Initiation Protocol (SIP) communications. In at least one implementation, a method of operating a communication network utilizing a session initiation protocol (SIP) is provided. The method performed within a second communication device includes receiving a SIP invite from a first communication device, and determining a source IP address for the second communication device, using an IP address for a third communication device as a destination address within a source address selection algorithm (SASA) function. The method further includes adding a Via header within the SIP invite to include the SASA determined source IP address for the second communication device, adding a Record-Route header within the SIP invite to include the SASA determined source IP address for the second communication device, and transferring the modified SIP invite to the third communication device.
1. A method of operating a communication network utilizing a session initiation protocol (SIP), the method comprising:
within a second communication device:
receiving a SIP invite from a first communication device;
determining a source IP address for the second communication device, using an IP address for a third communication device as a destination address within a source address selection algorithm (SASA) function;
adding a Via header within the SIP invite to include the SASA determined source IP address for the second communication device;
adding a Record-Route header within the SIP invite to include the SASA determined source IP address for the second communication device; and
after adding the Via header and the Record-Route header, transferring the SIP invite to the third communication device.
2. The method of claim 1 , wherein adding the Record-Route header within the SIP invite further comprises:
if a source address of an inbound connection of a previous hop is different from a source address of an inbound connection of a next hop, adding a first Record-Route header within the SIP invite including the source address of the inbound connection of the previous hop and adding a second Record-Route header within the SIP invite including the source address of the inbound connection of the next hop.
3. The method of claim 1 , wherein the SASA determined source IP address for the second communication device is an IPv4 IP address or an IPv6 IP address.
4. The method of claim 1 , wherein the SASA determined source IP address for the second communication device added to the Via header is determined using a source IP address of an outbound socket to a next hop.
5. The method of claim 1 , wherein the SASA determined source IP address for the second communication device is determined using a SASA getsocname( ) function.
6. The method of claim 1 , wherein the third communication device is a session manager or proxy in communication with a fourth communication device.
7. The method of claim 1 , wherein the source addresses of incoming connections are determined using a SASA getsocname( ) function using an IP address of a downstream entity as the destination address, and the source addresses of outgoing connections are determined using a SASA getsocname( ) function using an IP address of an upstream entity as the destination address.
8. A computing apparatus comprising:
one or more non-transitory computer readable storage media;
a processing system operatively coupled with the one or more non-transitory computer readable storage media;
program instructions stored on the one or more non-transitory computer readable media to operate an end user communication device that, when executed by the processing system, direct the processing system to:
receive a SIP invite from a first communication device;
determine a source IP address for the computing apparatus, using an IP address for a second communication device as a destination address within a source address selection algorithm (SASA) function;
add a Via header within the SIP invite to include the SASA determined source IP address for the computing apparatus;
add a Record-Route header within the SIP invite to include the SASA determined source IP address for the computing apparatus; and
transfer the SIP invite to the second communication device after the Via header and the Record-Route header are added.
9. The computing apparatus of claim 8 , wherein add the Record-Route header within the SIP invite further comprises:
if a source address of an inbound connection of a previous hop is different from a source address of an inbound connection of a next hop, add a first Record-Route header within the SIP invite including the source address of the inbound connection of the previous hop and add a second Record-Route header within the SIP invite including the source address of the inbound connection of the next hop.
10. The computing apparatus of claim 8 , wherein the SASA determined source IP address for the computing apparatus is an IPv4 IP address or an IPv6 IP address.
11. The computing apparatus of claim 8 , wherein the SASA determined source IP address for the second communication device added to the Via header is determined using a source IP address of an outbound socket to a next hop.
12. The computing apparatus of claim 8 , wherein the SASA determined source IP address for the computing apparatus is determined using a SASA getsocname( ) function.
13. The computing apparatus of claim 8 , wherein the second communication device is a session manager or proxy in communication with a third communication device.
14. The computing apparatus of claim 8 , wherein the source addresses of incoming connections are determined using a SASA getsocname( ) function using an IP address of a downstream entity as the destination address, and the source addresses of outgoing connections are determined using a SASA getsocname( ) function using an IP address of an upstream entity as the destination address.
15. A communication system for operating a communication network utilizing a session initiation protocol (SIP) comprising:
a first communication device; and
a second communication device, coupled with the first communication device, wherein the second communication device is configured to:
receive a SIP invite from a first communication device;
determine a source IP address for the second communication device, using an IP address for a third communication device as a destination address within a source address selection algorithm (SASA) function;
add a Via header within the SIP invite to include the SASA determined source IP address for the second communication device;
add a Record-Route header within the SIP invite to include the SASA determined source IP address for the second communication device; and
transfer the SIP invite to the third communication device after the Via header and the Record-Route header are added.
16. The communication system of claim 15 , wherein add the Record-Route header within the SIP invite further comprises:
if a source address of an inbound connection of a previous hop is different from a source address of an inbound connection of a next hop, add a first Record-Route header within the SIP invite including the source address of the inbound connection of the previous hop and add a second Record-Route header within the SIP invite including the source address of the inbound connection of the next hop.
17. The communication system of claim 15 , wherein the SASA determined source IP address for the second communication device is an IPv4 IP address or an IPv6 IP address.
18. The communication system of claim 15 , wherein the SASA determined source IP address for the second communication device added to the Via header is determined using a source IP address of an outbound socket to a next hop.
19. The communication system of claim 15 , wherein the SASA determined source IP address for the second communication device is determined using a SASA getsocname( ) function.
20. The communication system of claim 15 , wherein the third communication device is a session manager or proxy in communication with a fourth communication device.