With the rapid development of IP network, high bandwidth provides a good channel guarantee for video transmission,
In the IPTV scheme, there are multicast and unicast schemes,
At present, the two methods are also widely used in practical applications, and each has its own disadvantages:
The advantage of the unicast method is that it is relatively simple and has no special requirements for the network and equipment.
It is more convenient to implement across different operators' networks, and it is also a method that is widely used at present.
The disadvantage is that each user has to establish a one-to-one communication thread with the server,
When the number of users increases, there will be greater pressure on the line and CDN server.
The multicast method is relatively complicated, mainly because of the large number of device configurations.
Multicast will be forwarded as broadcast packets on Layer 2 access devices that do not enable multicast or do not support multicast.
will stress the network without multicast users; on devices that support multicast,
Multicast delivery can be performed only to terminals that have multicast packet requests.
No forwarding is performed on ports that do not have multicast packet requests, and there is no situation that affects other users.
Its biggest advantage is that when multiple people visit at the same time,
Only one request message transmission for the same source is required,
Layer 2 devices only forward copies to multiple people at the same time.
Using UDP transmission, no two-way communication with each client,
The device performance and resource occupation are less.
plan selection
Considering the advantages and disadvantages of single and multicast methods,
After discussions with the development company of the set-top box, the final choice of live broadcast content is mainly multicast.
The unicast mode is supplemented, and the multicast mode is preferentially used on the set-top box that can receive the multicast source.
Use unicast sources on set-top boxes that cannot receive multicast.
Non-live festivals that require separate responses, such as time-shift and on-demand, use unicast sources.