3Com 3C892 - OfficeConnect ISDN Lan Modem Router User Manual page 104

How do different
devices communicate
with each other?
What is TCP/IP?
¤
OfficeConnect
ISDN LAN Modem
LAN STATUS
OfficeConnect ®
Tx Coll 1 2 3 4
Alert PWR ISDN B1 B2 ISDN LAN Modem
Figure 56 Two Simultaneous Connections
The B channels may also be combined using the Multilink PPP feature to allow one
higher speed connection to a single location as shown in Figure 57.
¤
OfficeConnect
ISDN LAN Modem
LAN STATUS
®
OfficeConnect
Alert PWR ISDN B1 B2 Tx Coll 1 2 3 4 ISDN LAN Modem
Combining both
B channels with Multilink
provides a single 128 Kbps*
connection
*Without compression.
Figure 57 Using Multilink to Combine B Channels for a Single High-Speed Link
Once the computers are physically connected in a network, they must run some
type of standard communications software that allows different types of
computers to communicate with each other. Transmission Control
Protocol/Internet Protocol (TCP/IP) is becoming the most common software used
to accomplish this.
TCP/IP is a standardized communications protocol that works across LANs and
WANs, allowing different devices to communicate with each other. As its name
indicates, TCP/IP has two main components, TCP and IP. TCP manages the transfer
of data and corrects any errors that occur during transmission. It ensures that data
is reliably transferred. IP routes the data in packets from one location to another
across a network using the source and destination information within each data
packet to determine routing and destinations.
Note that TCP/IP encompasses more than the two protocols which define its
name. It comprises a set of software applications that allow various network
services such as remote file transfer protocol (FTP), remote login (Telnet), and
e-mail Simple Mail Transfer Protocol (SMTP) and Post Office Protocol (POP) 3.
Internet/Intranet or
B channel 1
B channel 1
Public telephone
B channel 2
3 Com
network
ISDN BRI line
Internet/Intranet or
128 Kbps B1 & B2
64 Kbps B1
Public telephone
64 Kbps B2
3 Com
network
What is a network?
online service
Remote office
LAN
B channel 2
online service
Remote office
LAN
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