Ds0 Signaling And Dynamic Bandwidth Allocation - 3Com 3C63400-3AC-C - PathBuilder S700 Switch Reference Manual

92 C 4: P B
HAPTER ATH UILDER
S700 M A
ODULE AND PPLICATION

DS0 Signaling and Dynamic Bandwidth Allocation

Structured DS0s provide channel associated signaling (CAS) by providing a path
for DS0 ABCD bits. See Figure 55.
Channel associated signalling allows telephone supervision to be signaled end to
end. Note that structured DS1 CBR occupies only the needed bandwidth for the
DS0s selected.
Figure 55 Channel Associated Signaling
Channel
Bank
These frames are then followed by the ABCD bits of each active DS0. Two DS0s
ABCD bits are provided in each byte after the last DS0 group. Figure 56 illustrates
an example of 3 DS0s and their ABCD bits sent in a structured encapsulation.
Figure 56 Multiframe Structure for 3x64kbit/s DS1 or E1 with CAS
AAL1 Pointer
. . .
ABCD for
First
Transported
Timeslot
ABCD for
Third
Transported
Timeslot
ABCD for Second
Transported Timeslot
O
VERVIEW
DS0
A&B Bits
Channel Associated
Signaling (CAS)
First Transported Octet of Multiframe
Second Transported Octet of Multiframe
First 125 µsec Frame of Multiframe for
DS1
Second 125 µsec Frame of Multiframe for
DS1
Last 125 µsec Frame of Multiframe for
DS1
Signaling
Substructure