24 ĐỀ THAM KHẢO KÌ THI TUYỂN SINH VÀO LỚP 10 MÔN TIẾNG ANH SỞ GIÁO DỤC HẢI DƯ...
Sw2 presentation homework week11
1. How Circuit-Switched Digital
Networks Work
・ Central Office(CO)
・ Telephone company
・ TCP/IP
・ Circuit-Switched Networks Event Timing Diagram
2. Central Office(CO)
A central office is the physical building used to
house inside plant equipment including
telephone switches, which make telephone
calls "work" in the sense of making connections
and relaying the speech information.
VOICE
Street Cabinet Central Office subscriber
DATA
3. Telephone company
A telephone company (also known as a telco or
telecommunications operator) is a service
provider of telecommunications services such as
telephony and data communications access.
Many were at one time nationalized or state-
regulated monopolies.
This picture is The Edison Bell Telephone Company building of 1896 in Birmingham, England
4. TCP/IP
The Transmission Control Protocol (TCP) is one
of the core protocols of the Internet Protocol Suite.
TCP is one of the two original components of the
suite, complementing the Internet Protocol (IP),
and therefore the entire suite is commonly
referred to as TCP/IP.
5. Circuit-Switched Networks Event Timing Diagram
Below schematic depicts the transmission of data (a message) across four
nodes in a circuit-switched network. The primary components of delay in
circuit switching are the propagation delay of the signaling message on
each link ( Dp ), the processing delay of the signaling message at each node
( Dn ), and the transmission delay of data traffic ( Dt ).
Once the destination receives the call request, assuming the destination is
not busy, it will return an acceptance message. On the return path, no
processing delay at intermediate nodes will be required since the
connections are already set up. This operation is referred to as forward
reservation. In reverse reservation, however, the setup message will be
directly sent to the destination and resource reservation at intermediate
nodes occurs as the acceptance message is received; this is to avoid any
resource reservation before ensuring that the end-to-end path is available.
As shown in the figure, before the data (or message) is sent, a certain
amount of elapsed time is required to setup the path. First, a setup
message is sent through the network to setup a connection to the
destination. Processing delay is the time spent at each node setting up the
route of the connection.
