Why sip is better than h.323

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.

Typically, H. There are several channels in H. While control channel defined to be transported over a reliable transport protocol like TCP. Similar to H. So, the difference between H. SIP is an application layer control protocol used to set-up, modify and end multimedia sessions or calls. Although, it manages the communication between the caller and callee, which includes endpoint addressing and user location.

Servers are not necessarily needed for a basic SIP call. The INVITE message holds the session specification that notifies about the type of media the caller can accept and the destination of the media data. Session Initiation Protocol is similar to H. SIP is an application layer which is enabled to control to setup or modulate multimedia call or session. This is a guide to H. Here we discuss the difference between H. You can also go through our other suggested articles to learn more—.

Submit Next Question. To compound the problem—to further propagate the error, as it were—we have also seen several papers written by naive students and rank-and-file engineers that blindly parrot what they have read in these comparisons.

Furthermore, many, many people have formed their opinions of H. To counter this misinformation, we decided to put together this thorough, up-to-date comparison.

As with ours, please consider the financial interests of the source of any information on this subject, be it an author, speaker, institution, forum, company, web site, or conference. Are the people providing information on this issue involved in both of these—and other—protocols and have nothing besides perhaps an honest academic interest in one or the other protocol, or have they otherwise "hitched their wagon" to one?

Like everything else on the web, this is a living document which we will be updating as the standards evolve. In fact, there is much work in progress for both H. Also, note that commentary that is not vital to the main comparison text appears in a smaller font immediately below it.

As a result, it might be reasonable for users to expect about the same level of robustness and interoperability as is found on the PSTN today, although this admittedly varies across the globe. The most widely deployed use of H. SIP was designed to setup a "session" between two points and to be a modular, flexible component of the Internet architecture. It has a loose concept of a call that being a "session" with media streams , and has no intrinsic support for multipoint multimedia conferencing though implementers have built conferencing services to provide conferencing support.

SIP is now. Though there have been some efforts to create a more modern communication standards, companies thus far have either elected to keep using these old systems, create proprietary systems that do not interwork to a significant degree, or focus effort on web-based conferencing i. No communication system is simple, but H. SIP was initially focused on voice communication and then expanded to include video, application sharing, instant messaging, presence, etc.

With each capability, complexity increases and, unfortunately, there are no strict guidelines as to what functionality any given device must support. This leads to more complex systems with more interoperability problems.

SIP was "marketed" as a simple protocol, in spite of the fact it only looks simple on the surface. Telephony is a hard problem and, regardless of how one wants to deliver it, the total system is going to have a certain level of complexity out of necessity. SIP has not defined procedures for handling device failure.

If a proxy fails, the user agent detects this through timer expiration. It is the responsibility of the user-agent to send a re-INVITE to another proxy, leading to long delays in call establishment. Messages are efficiently encoded and decoded by machines, with decoders widely available e. As a result, effort has been made to binary encode SIP e. Globally unique identifiers prevent feature and data element collision. SIP is extended by adding new header lines or message bodies that may be used by different vendors to serve different purposes, thus risking interoperability problems.

The risk is admittedly small, but this problem has already been seen in the real world with similar extension schemes. However, new revisions of H. SIP is extended by the standards community to add new features to SIP in such a way as to not impact existing features. However, new revisions of SIP are potentially not backward compatible e. In addition, several extensions are "mandatory" in some implementations, which cause interoperability problems. In addition, endpoints report their available and total capacity so that calls going to a set of gateways, for example, may be best distributed across those gateways.

There is no means of detecting the load on a particular gateway or to know whether a device has failed, meaning that proxies simply have to try a PSTN gateway, wait for the call to timeout, and then try another. When an H. In large networks, the direct call model may be used so that endpoints connect directly to one another. When using a SIP proxy to perform address resolution for the SIP device, the proxy is required to handle at least 3 full message exchanges for every call.

In large networks, such as IMS networks, the number of messages on the wire may be excessive. A basic call between two users may require as many as 30 messages on the wire! The H. The endpoint does not have to be concerned with the mechanics of this process, and the processing requirements for address resolution placed on the gatekeeper by H. Although out of scope of H. The endpoint does not have to be concerned with the mechanics of this process.