sonet 101

What is SONET?
STS Path
Overhead
First DS-1
Second DS-1
Third DS-1
Fourth DS-1
DS-2
Because all virtual
tributaries are
identifiable, it is easy
to tell the bytes that
belong to each DS-1.
125 ms
16
1
•
•
•
•
•
•
•
9
Section
Overhead
Line Overhead
VT
1.5
VT
1.5
VT
1.5
VT
1.5
1 (Bytes) • • • • • • • • • • • • • • • • • • 90
VT
6
51.84 Mbps Building Block (STS-1)
VT Path Overhead
VT-1.5 VT-2 VT-2 VT-6
Sizes of Virtual Tributaries
Figure 1-7 • DS-1 Visibility