Avaya T3 Comfort, Service Manual

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General explanations
7
General explanations
Basic information about IP telephones can be found in the Service Manual T3 IP
connected to Integral 5, order number 4.999.105.974. This manual provides basic
information about DHCP, MAC addresses, IP addresses, Subnet masks and FTP.
How does the IP telephone communicate with the IP Office?
Communication between an ISDN terminal and the IP Office
•
The configuration data (e.g., for establishing and disconnecting a connection
during setup for example) are transferred to/from the system in the D channel
of layer three.
•
The voice data are sent via the B channel.
Communication between an IP telephone and the IP Office
D and B channel information the same as ISDN exist here also. Due to the fact that
there is no ISDN connection, however, the ISDN data must be sent to the recipient in a
different way.
Generally speaking, the IP phone and the IP Office communicate via the TCP/IP
protocol.
•
Layer 3
of the OSI layer model is the
switching layer
. This layer is used to
establish the connection between the end systems (IP telephone-IP Office).
Information regarding the transmitting and receiving station is included in the
message packets.
The
data packages
are addressed in this layer. The
IP
protocol
(TCP /
IP
) applies here. This layer is also responsible for routing in
complex networks, in other words establishing the route for getting the data
packages through to the end station. At the appropriate point in the IP header,
it is indicated which protocol of higher-level layers will be prefixed to the data
portion next, e.g.
06 = TCP
or
17 = UDP
.
•
Layer 4
of the OSI layer model is the
transport layer
. This layer is responsible
for establishing and controlling connections between communication partners.
Communication partners are communication applications in this context. These
applications must be addressed and data loss in a connection detected and
resolved. The transport layer is the link between the transport and application
system. It doesn’t matter to the functions of the application system what type of
network the messages come from or are forwarded from. The protocols
TCP
(
T
ransmission
C
ontrol
P
rotocol) or
UDP
(
U
ser
D
atagram
P
rotocol) apply here.