# Enabling fast call setup

The 3G-324M Interface supports the following techniques for speeding up 3G-324M call setup time:

- Packed H.245 messages

- WNSRP

- MONA

Note: You must obtain the appropriate license to use one of these techniques. For information, see the readme file for this release.

## Packed H.245 messages

Packed H.245 messages allow grouping independent H.245 messages together into a single NSRP command frame. This reduces the number of message round-trips, and thus reduces call setup time. NMS optimizes this technique to achieve smart grouping of messages.

You can enable the packing of H.245 messages by setting the pack_h245 parameter to 1 in the H.324 Middleware configuration file. For information, see Initializing the H.324M Middleware.

## WNSRP

WNSRP (Windowed Simple Retransmission protocol) is an H.245 transport improvement technique that is standardized in ITU-T Recommendation H.324 and accepted into the 3G-324M standard by 3GPP. WNSRP introduces a transmission window for the WNSRP messages sent by a terminal. The transmission of WNSRP H.245 messages allows for multiple independent messages to be sent without acknowledgement, which results in a more efficient use of bandwidth for each message.

The 3G-324M Interface supports WNSRP. The Interface falls back to regular NSRP for compatibility with non-WNSRP terminals.

Enable WNSRP by setting the nsrp_mode parameter to 3 in the H.324 Middleware configuration file. For information, see Initializing the H.324M Middleware.

## MONA

MONA (media oriented negotiation acceleration), formally known as ITU-T Recommendation H.324 Annex K, was approved by the ITU-T in August 2006, and is recommended in 3GPP Release 7 in TR 26.911. MONA unites the technologies for H.324 call setup acceleration under a common framework.

The following table describes the MONA capabilities that the 3G-324M Interface supports:

Supported MONA capability | Description
Exchange of fast call setup capabilities and preferences for MPC MONA call setup | The 3G-324M Interface supports the use of MONA Media Pre-Configured Channels (MPC) to achieve the fast setup of media sessions. When multiple video codecs are supported by the application, only the preferred codec is used for the MONA MPC fast call setup attempt. The preferred codec is the first codec passed by the application to the H.324M Middleware. MONA MPC relies on specific codec configurations, so that the codec configuration does not have to be negotiated. When encoding video, use the configurations defined by MONA. For information, see ITU-T H.324 Annex K.
Fallback to MONA ACP technique | If the MONA MPC negotiation fails, the 3G-324M Interface uses accelerated H.245 signaling (ACP) as a fallback negotiation technique.
Fallback to regular call setup against legacy terminals | The 3G-324M Interface is fully compatible with legacy 3G-324M terminals.

You can enable MONA by setting the mona parameter to 1 in the H.324 Middleware configuration file. As recommended by 3GPP, always enable WNSRP when you enable MONA. For information about enabling MONA and WNSRP, see Initializing the H.324M Middleware.

### Not supported

The 3G-324M Interface does not support:

- The Signaling Pre-Configured Channel (SPC) MONA technique.

- Pre-configured Channel Media frames encapsulated in MONA signaling Preference Messages.