Use the WebAdmin Interface to configure the XIMSS module. Open the Access page in the Settings realm:

Processing
Log Level:	Crashes OnlyFailuresMajor & FailuresProblemsLow LevelAll Info	Channels:	off135102550100250500100030001000030000other	Listener

Use the Log setting to specify the type of information the XIMSS module should put in the Server Log. Usually you should use the Major (message transfer reports) or Problems (message transfer and non-fatal errors) levels. But when you experience problems with the XIMSS module, you may want to set the Log Level setting to Low-Level or All Info: in this case protocol-level or link-level details will be recorded in the System Log as well. When the problem is solved, set the Log Level setting to its regular value, otherwise your System Log files will grow in size very quickly.

The XIMSS module records in the System Log are marked with the XIMSSI tag.

When you specify a non-zero value for the Maximum Number of Channels setting, the XIMSS module creates a Listener. The module starts to accept all XIMSS connections that clients establish in order to communicate with your Server. The setting is used to limit the number of simultaneous connections the XIMSS module can accept. If there are too many incoming connections open, the module will reject new connections, and the client should retry later.

By default, the XIMSS module Listener accepts clear text connections on the TCP port 11024. Follow the Listener link to tune the XIMSS Listener.

XIMSS connections can be made to TCP ports served with other CommuniGate Pro modules. If the first symbol received on a connection made to the HTTP module is the < symbol, the HTTP module passes the connection to the XIMSS module.

When a connection is passed:

• the logical job of the passing module completes.
• the logical job of the XIMSS module is created, in the same way when an XIMSS connection is received on a port served with the XIMSS module.
• the XIMSS module restrictions for the total number of XIMSS channels and for the number of channels opened from the same IP address are applied.

When all users initiate XIMSS connections via other Module ports, you can disable the XIMSS Listener by setting all its ports to zero.

When a Flash client connects to an XMLSocket server (such as the CommuniGate Pro XIMSS module), it can send a special policy-file-request request. The XIMSS module replies with an XML document allowing the client to access any port on the Server.

When a user is authenticated, the XIMSS module creates a XIMSS session. The current XIMSS module TCP connection can be used to communicate with that session.

A XIMSS session can be created without the XIMSS module, using special requests sent to the HTTP User module. See the XIMSS Protocol section for more details.

The XIMSS session records in the System Log are marked with the XIMSS tag.

Codecs Av01008m08 399 Opus 251 New 〈90% COMPLETE〉

Example yt-dlp -F output snippet:

Earlier AV1 adoption was limited to software decoding, which was resource-intensive. By 2026, most modern CPUs and GPUs support hardware acceleration for AV1 , making the av01 stream smooth and efficient on laptops, phones, and TVs.

audio codec, which YouTube uses for its highest quality audio streams.

If you're reviewing or investigating the use of the Opus codec with specific settings (like "251") and a unique identifier or device specification ("AV01008M08" and "399"), consider the following: codecs av01008m08 399 opus 251 new

This string identifies a combination of the cutting-edge and the highly efficient Opus audio codec . Together, they form the bedrock of next-generation media delivery across the internet. Decoding the Technical String

Older Firefox versions or Linux configurations might struggle with av01 VA-API playback. If you encounter black screens, users often suggest forcing VP9 via about:config (media.av1.enabled = false), though this increases data usage.

: This is another YouTube ITAG identifier. On the platform, ITAG 251 represents the highest standard audio quality available for free users. It delivers a Variable Bitrate (VBR) stream hitting a ceiling of roughly 160 kbps at a 48 kHz sampling rate . The Power of AV1 Video Compression Example yt-dlp -F output snippet: Earlier AV1 adoption

parts = codec_str.split()

is currently the king of internet audio. It is a codec so advanced it can switch between speech and music modes in real-time. In the standard YouTube Itag list, 251 specifically refers to Opus audio inside a WebM container, usually at a bitrate around 160 kbps.

: This prefix identifies the codec as AV1 , short for AOMedia Video 1. Developed by the Alliance for Open Media, a consortium of major tech companies including Google, Mozilla, Microsoft, and Amazon, AV1 is a royalty-free and highly efficient video coding format. It's the modern successor to H.264 and VP9, designed to deliver the same visual quality as its predecessors but at a significantly lower bitrate, meaning smaller file sizes and faster streaming. In web development, this codec string is used in the type attribute of an HTML <source> element to help browsers decide which video file to play. If you're reviewing or investigating the use of

Opus is a relatively new codec that has gained significant traction in recent years. Developed by the Internet Engineering Task Force (IETF), Opus is an open-source, royalty-free codec designed to provide high-quality audio compression for a wide range of applications, from low-bit-rate speech to high-quality music. Opus has become a popular choice for audio compression due to its exceptional performance, flexibility, and adaptability.

The portion refers to the AV1 (AOMedia Video 1) codec, a royalty-free format designed to deliver high-quality video while using significantly less data than previous standards like H.264 or VP9. av01 : The identifier for the AV1 video codec.

: Represents the decoder capability "Level" and "Tier." The 08 refers to Level 4.0, which easily handles resolutions up to 1080p at 60 frames per second or standard 2K video. The M designates the Main Tier (as opposed to High Tier used for extreme high-bitrate applications).

This long string of characters is an ISO Media Quantification identifier for the AV1 video codec. AV1 (AOMedia Video 1) was developed by the Alliance for Open Media—a consortium including Google, Apple, Microsoft, and Netflix—to replace older, royalty-heavy codecs like HEVC/H.265.

(Variable Bitrate), many audiophiles report it sounds superior to AAC at Sample Rate : Opus operates at a sampling rate, whereas the standard AAC (140) often uses Frequency Range : Opus can maintain frequencies up to

You can monitor the XIMSS Module activity using the WebAdmin Interface.

Click the Access link in the Monitors realm to open the Access Monitoring page:

3 of 3 selected

ID	IP Address	Account	Connected	Status	Running
9786	[216.200.213.116]	user1@domain2.dom	3min	listing messages	2sec
9794	[216.200.213.115]	user2@domain1.dom	34sec	reading request
9803	[216.200.213.115]		2sec	authenticating

ID

This field contains the XIMSS numeric session ID. In the CommuniGate Pro Log, this session records are marked with the XIMSS-nnnnn flag, where nnnnn is the session ID.

IP Address

This field contains the IP address the client has connected from.

Account

This field contains the name of the client Account (after successful authentication).

Connected

This field contains the connection time (time since the client opened this TCP/IP session).

Status

This field contains either the name of the operation in progress or, if there is not pending operation, the current session status (Authenticating, Selected, etc.).

Running

If there is an XIMSS operation in progress, this field contains the time since operation started.

XIMSS activity can be monitored with the CommuniGate Pro Statistic Elements.