Oracle Video server, Manual

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Networking in the OVS System
2-32 Introducing Oracle Video Server
PSTN
In Internet environments, clients communicate with both an ISP (Internet Service
Provider) and the OVS. These communications use separate network connections:
■
Clients communicate with an ISP through a PSTN using IP. A PSTN may
consist of:
■
POTS (plain old telephone service)
■
ISDN (Integrated Services Digital Network)
■
ADSL (Asymmetric Digital Subscriber Loop)
■
Clients communicate with the OVS through a TCP or UDP network connection.
LAN
In intranet environments, the OVS system uses switched Ethernet on a LAN to
ensure consistent error-free video delivery and to reduce network congestion.
Unlike shared Ethernet in which every computer reads every data packet, switched
Ethernet uses a hardware hub that provides a dedicated link to each client. The
dedicated link allows the hub to physically map each client IP address to the
communication channel between the hub and the client. The switched Ethernet hub
examines the IP address of each packet as it moves through the hub and routes it
directly to its destination segment ensuring that data in the communication channel
between the hub and a client is destined for that client. Each client views only its
data and does not spend time examining packets addressed to others on the same
communication channel.
The switched Ethernet hub also has high capacity input allowing for the
multiplexing of video streams from the server to many clients from a single line. A
high capacity interface, such as FDDI (Fiber Distributed Data Interface) or CDDI
(Copper Distributed Data Interface), handles many video streams from the video
server computer at once, with a dedicated segment for each client, ensuring
optimum performance for both the dedicated segments and the entire network.
The rest of this section explains why an OVS system using a LAN requires
switched Ethernet and discusses these topics:
■
Ethernet
■
Demands of Video on LANs