Common terms and concepts for Alibaba Cloud Real-Time Communication (RTC)-Real-Time Communication(RTC)-阿里云帮助中心

This topic explains common terms and concepts for Alibaba Cloud Real-Time Communication (RTC).

Common term	Description
Application ID (AppID)	An application ID is a basic business unit of RTC. Each application is assigned a unique ID. You can create multiple application IDs. You can create multiple channels for an AppID.
Channel	RTC unifies various names such as meeting and room into the single term "channel". Users within the same channel can communicate with each other.
Communication	A session starts when a device joins a channel. The session is not affected by whether the device publishes or subscribes to streams, or by the number of streams published or subscribed to.
User ID (UserID)	RTC uses a UserID to identify a user. UserIDs are generated by your business system. The number of UserIDs corresponds to the number of users of the RTC service.
Cumulative users	The total number of unique UserIDs within a statistical period. For a channel, the statistical period for cumulative users is the duration of a single session.
Device	The unique ID of a device that joins a session. This is called the User Device ID (UDID). Each hardware device has a unique UDID, which is maintained by Alibaba Cloud RTC.
Peak concurrent channels	The minimum statistical period for concurrency is 1 minute. The daily peak is the highest concurrency value recorded in any 1-minute period throughout the day. For real-time data, the current peak is the maximum concurrency value from 00:00 on the current day to the current time.
Peak concurrent sessions	The minimum statistical period for concurrency is 1 minute. The daily peak is the highest concurrency value recorded in any 1-minute period throughout the day. For real-time data, the current peak is the maximum concurrency value from 00:00 on the current day to the current time.
Service type	Services tailored for different scenarios. Currently, only a general-purpose service is available.
Service area	RTC is a global service. However, different pricing policies apply to different geographic regions. Currently, only one service area is available: China.
Media track	A data stream of specific media content, such as an audio stream (audio track) or a video stream (video track). The Alibaba Cloud RTC software development kit (SDK) currently supports one audio track and two video tracks. Video tracks are categorized as camera tracks and screen tracks. A camera track is content from a camera or any source other than the screen. A screen track is content from screen sharing.
Simulcast	The process of encoding the same video content into multiple, independent streams using different encoding methods or parameters. The Alibaba Cloud RTC SDK currently supports Simulcast only for camera tracks.