MCSE : Security Specialist
T1/E1
A
1.544 Mbps point to point dedicated, digital circuit provided by the
telephone companies. T1 lines are widely used for private networks
as well as interconnections between an organizations LAN and the
telco.
A T1
line uses two pairs of wire one to transmit, and one to receive. and
time division multiplexing (TDM) to interleave 24 64-Kbps voice or
data channels. The standard T1 frame is 193 bits long, which holds
24 8-bit voice samples and one synchronization bit with 8,000 frames
transmitted per second. T1 is not restricted to digital voice or to
64 Kbps data streams. Channels may be combined and the total 1.544
Mbps capacity can be broken up as required.
T3/E3
A T3
line is a super high-speed connection capable of transmitting data
at a rate of 45 Mbps. A T3 line represents a bandwidth equal to
about 672 regular voice-grade telephone lines, which is wide enough
to transmit real time video, and very large databases over a busy
network. A T3 line is typically installed as a major networking
artery for large corporations, universities with high-volume network
traffic and for the backbones of the major Internet service
providers.
OC
Optical Carrier, designations are used to specify the speed of fiber
optic networks that conforms to the SONET standard.
|
Level
|
Speed
|
|
OC-1 |
51.85 Mbps |
|
OC-3 |
155.52 Mbps |
|
OC-12 |
622.08 Mbps |
|
OC-24 |
1.244 Gbps |
|
OC-48 |
2.488 Gbps |
|
