Streaming Media Supplement sa2150 and sa2250

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Chapter 1
TCP.
Transmission Control Protocol; based on RFC 793. Used as the underlying transport protocol by the
control channel, and sometimes by the data transfer channel. Based on the principle of a TCP connection
between nodes (for example, between a Web client and a proxy cache, or between a proxy cache and an origin
server). See “UDP” .
Transparency.
A transparency device (a layer 4 switch or WCCP2-compatible router) provides transparency
by looking into the TCP packet of incoming traffic, determining which protocol the traffic is using, and making
routing decisions based on what it finds. See “Transparent proxy caching” .
Transparent proxy caching.
When clients are not configured to explicitly direct their requests to a proxy
cache, but the network is designed so that a proxy cache server receives the client requests anyway, the proxy
cache is transparent to the client.
Requires a transparency device (a layer 4 switch or WCCP2-compatible router) to intercept traffic (by protocol)
and redirect it to the proxy cache.
UDP.
User Datagram Protocol; based on RFC 768. Used as the underlying transport protocol by the data
transfer protocols. Operates in a connectionless manner. See “TCP” .
Underlying transport protocol.
A protocol that takes care of the transport of bits; is used by, or lies
underneath, another protocol, which may be a data transfer protocol or a control protocol. See “Control
protocol” and “Data transfer protocol” .
Upper level.
Part of hierarchy closer to content.
Upstream.
The host closer to the origin server or originator of the content.
VIP failover.
Stands for Virtual IP failover. In a Media-IXT cluster, a pool of virtual IP addresses is assigned
to the nodes in the cluster. In VIP failover, when one node fails, the node with the lowest IP address assigns
another node to take over the traffic that would normally go to the down node.
Windows Media Technologies.
A streaming media format from Microsoft; the client is a browser equipped
with Windows Media Player, and the origin server is Windows Media server. Abbreviated as WMT. See “ASF”
, “ASX” and “MMS” .