According to survey analysis, approximately 70% of the information humans acquire comes through vision. As the scope of video technology applications continues to expand, for video conferencing systems that rely on network operation, the network environment plays a decisive role in meeting quality. Video conferencing has the following network access methods:
IP-Based Network Systems
For small and medium-sized users and individual users with sufficient network bandwidth, an IP-based network is arguably the best choice. IP networks are what we commonly refer to as broadband networks. This network access method is simple, affordable, and widely used. Based on various transmission media, this network adopts the TCP/IP protocol as its communication protocol and uses routers for networking to achieve routing and switching transmission of IP data packets.
Typically, to better address the service quality of real-time communication, protocols such as UDP/IP, RTP, RTCP, and RSVP are employed. Currently, video conferencing systems applied over broadband IP networks like ADSL and FTTB+LAN have achieved excellent results. However, because packet-switched IP networks follow a best-effort delivery principle, the video conferencing quality of this access method is inferior compared to dedicated lines like ISDN and DDN. Nevertheless, its excellent cost-effectiveness has won the favor of an increasing number of users.
Using ATM Networks
For users with existing line infrastructure and very high quality requirements, ATM networks are recommended. ATM, or Asynchronous Transfer Mode, combines the advantages of circuit switching and packet switching. It can transmit broadband signals at any rate and carry voice, data, image, and video services.
It is worth mentioning that the biggest feature of this technology is its QoS guarantee, which can output very high-quality images. Networking is convenient, as not all video conferencing terminal lines need to be connected to the MCU, and reliability is relatively high. If high-quality video effects are desired and ATM network access is readily available, it is also a good choice.
One thing users should note here is that the equipment cost for this solution is high, and it requires a dedicated ATM network connection. Users should plan and deploy based on their own conditions to avoid unnecessary capital waste.
Using ISDN Line Access
ISDN, or Integrated Services Digital Network, uses the public telephone network to provide users with end-to-end digital channel connections, used to carry various telecommunication services including voice and non-voice. It utilizes ISDN lines to transmit video conferencing over ISDN channels, with speeds reaching from 384kb/s to 2Mb/s.
Since ISDN is billed based on the used B channels (64kb/s) for communication, and the domestic communication rate for one B channel is equivalent to the ordinary telephone communication rate, for users with low communication volume and short communication times, choosing ISDN incurs lower costs. Moreover, the national ISDN network is still in a phase of continuous upgrading, and its reliability and stability still need improvement compared to dedicated line methods.
Leased DDN Dedicated Line Systems
Generally speaking, large enterprises and institutions often have high requirements for video quality, making DDN dedicated line access a suitable choice. DDN dedicated lines offer high transmission quality, low network latency, highly reliable circuits, high network security, and convenient networking.
DDN refers to a data transmission network that uses digital channels to transmit data signals. Its primary role is to provide users with permanent and semi-permanent connections for digital data transmission channels, usable for communication between computers, as well as for transmitting digitized fax, digital voice, digital image signals, or other digitized signals.
However, for users with short communication times, this method is not suitable because the digital circuits provided by DDN are semi-permanent connections, only appropriate for long-duration point-to-point and multipoint-to-multipoint communication connections. Billing is based on the number of point-to-point connections, making the cost too high for such users. Therefore, understanding one’s own needs is crucial when setting up the network.
Using Satellite Access Systems
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