Basis for comparison | H.323 | SIP |
---|---|---|
Origins | Telephony based | Internet-based |
Designed by | ITU (International Telecommunication Union) | IETF (Internet Engineering Task Force) |
Endpoint location | Utilizes alias (which is mapped by gatekeepers). | Uses SIP URLs. |
Call routing | The gatekeeper provides the routing information. | Redirect and location server provides routing information |
Message Format | Binary | ASCII |
Compatibility with Internet | No | Yes |
Architecture | Monolithic | Modular |
Instant messaging | Not provided | Provides instant messaging facility |
Scalability | Limited | Better |
Flexibility | H.323 is not flexible enough. | Highly flexible. |
Interoperability | Well defined protocols and complete backward compatibility makes it interoperable. | Does not provide interoperability. |
Ease of implementation | Need of special parser complicate the deployment and debugging. | Reusable elements easily conduct the implementation. |
Complexity | Quite complex | Moderate |