Field
Description
IP Pool Name
Enter the name of the IP pool.
IP Pool Range
In the first field, enter the first IP address of the range.
In the second field, enter the last IP address of the range.
17.2 ATM
ATM (Asynchronous Transfer Mode) is a data transmission procedure that was originally
designed for broadband ISDN.
ATM is currently used in high-speed networks. You will need ATM, for example, if you want
high-speed access to the Internet via the integrated ADSL or SHDSL modem.
In an ATM network, different applications such as speech, video and data, can be transmit-
ted side-by-side in the asynchronous time multiplex procedure. Each transmitter is provided
with time sections for transmitting data. With asynchronous transmission, unused time sec-
tions of a transmitter are used by another transmitter.
With ATM, the packet switching procedure is connected-based. A virtual connection is used
for data transmission that negotiates between the transmitter and recipient or is configured
on both sides. This determines the route that the data should take, for example. Multiple
virtual connections can be set up over a single physical interface.
The data is transmitted in so-called cells or slots of constant size. Each cell consists of 48
bytes of usage data and 5 bytes of control information. The control information contains,
amongst other things, the ATM address which is similar to the Internet address. The ATM
address is made up of the Virtual Path Identifier (VPI) and the Virtual Connection Identifier
(VCI); this identifies the virtual connection.
Various types of traffic flows are transported over ATM. To take account of the various de-
mands of these traffic flows on the networks, e.g. in terms of cell loss and delay time, suit-
able values can be defined using the service categories. Uncompressed video data, for ex-
ample, requires different parameters to time-uncritical data.
In ATM networks Quality of Service (QoS) is available, i.e. the size of various network para-
meters, such as bit rate, delay and jitter can be guaranteed.
OAM (Operation, Administration and Maintenance) is used to monitor the data transmission
in ATM. OAM includes configuration management, error management and performance
measurement.
Funkwerk Enterprise Communications GmbH
17 WAN
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