As the first step of live transmission, push stream scheduling has great influence on live link. This article will address this topic from the perspective of transmission
Netease cloud letterLive broadcast is how to do a good job of scheduling push flow.
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What is a live tweet
First of all, live streaming means that the host “pushes” out the video data collected and encoded by his or her local client.
Streaming involves two issues: where does the video go and where does the viewer pull the stream to the playback end.
The host pushes the stream to the live broadcast receiving server, which is responsible for distributing the stream to a higher transmission layer to push the video stream to the global audience. The live streaming server is the first station after the video stream starts from the client and also the station which has the greatest influence on the transmission quality. The problem of livestream uplink scheduling is to select an appropriate stream receiving server for the push stream client.
Scheduling and deployment of live streaming server
The scheduling and deployment of the live streaming server are of great importance:
First of all, due to the complexity of domestic network operators, there are many operators, small operators borrow large operation network and other problems. For live uplink scheduling, the first challenge is to identify the specific region and network type of customers. This step is usually handled through a network IP library. Although various IP network libraries exist on the network, accuracy is not guaranteed. Based on 20 years of Internet experience, NetEase Yunxin has accumulated a large amount of IP information and has its own IP library. Compared with the general IP library on the network, it can more accurately identify the problems of various regions and operators.
Secondly, it is the scheduling itself, that is, according to the source of customers, to the corresponding stream push server. The most common system is DNS based scheduling. NetEase cloud letter of course also supports this kind of scheduling. That is, a domain name is resolved by the AUTHORITATIVE DNS server of NetEase, and traffic receiving servers of the carrier and similar regions are assigned to the traffic pushing clients based on the carrier and region information. For example, if a user in Hangzhou uses the domain name xx.live.126.net to push the stream, it will first go to the DNS server for domain name resolution without considering the DNS cache. The DNS authoritative server of NetEase will finally receive the resolution request and provide an APPROPRIATE IP address for the incoming stream server according to the corresponding region and carrier identified in the IP database. Return to the client. The client can then push the stream to the receiving server.
DNS system is a general solution, the advantage is that there is no need for additional link intervention, directly based on DNS can achieve scheduling. However, its disadvantages are also quite prominent: DNS system for performance, do cache. If a traffic receiving server is down and unavailable for various reasons, the client will cache access to this machine as the traffic receiving server, which will cause the client to push the traffic is unavailable. The client needs to wait until the DNS cache becomes invalid before using the service, and the expiration time of the cache is complicated. Domestic carriers may extend the DNS cache, and the availability of the live streaming service cannot be guaranteed. On the other hand, the CLIENT IP address displayed by the DNS system is not necessarily the IP address of the client’s video stream egress, but the IP address of the local DNS egress, which may cause misjudgments by some DNS systems.
NetEase Cloud letter how to do a good job push flow scheduling
NetEase yunxin has its own live broadcast scheduling system. When a user uses the SDK of NetEase yunxin Live to broadcast, the SDK will contact the scheduling system of NetEase Yunxin to directly obtain the address of the stream receiving server. Due to netease cloud letter scheduling system deployed to select the multi-line BGP, with a number of small operators to pull the line, so small operators in users netease cloud scheduling system, will not go to a third party operators export, export, but walked straight line to the largest extent, reduce the scheduling system network operators for the users of miscalculation. The NetEase cloud communication dispatching system also has corresponding dispatching nodes overseas, that is, overseas clients can also obtain the appropriate address of the traffic receiving server.
On the other hand, there is a close connection between the scheduling system of NetEase Yunit and the upstream traffic receiving servers around the world, and the real-time CPU, memory, network and other resource usage of the traffic receiving servers will be monitored in real time, so as to finally give the most reasonable scheduling result.
By using NetEase Video SDK, users of NetEase Yunshun can skip the above possible PROBLEMS of DNS, conduct more accurate scheduling, and get better live streaming experience.
Uplink scheduling of live broadcast system affects the quality of the whole live broadcast to a great extent. If the upstream streaming server is not properly scheduled, for example, the client sends the video stream across the carrier due to the wrong identification of the client operator, the network is prone to instability and network congestion. NetEase Cloud Live streaming service ensures the accuracy of scheduling to the greatest extent through the above means.
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