
Agere Systems Inc.
153
Data Sheet
May 2001
and Packet Payload Engine
Ambassador T8110 PCI-Based H.100/H.110 Switch
14
Connection Control—Standard and Virtual Channel
(continued)
Notes:
Connectivity is as follows:
n
From
stream a, time slot n, bits[1:0]
to
stream e, time slot n + 10, bits[7:6].
n
From
stream b, time slot n + 1, bits[1:0]
to
stream e, time slot n + 10, bits[3:2].
n
From
stream c, time slot n + 2, bits[3:2]
to
stream e, time slot n + 10, bits[1:0].
n
From
stream d, time slot n + 3, bits[5:4]
to
stream e, time slot n + 10, bits[5:4].
Required connection memory programming is as follows:
Five 1/2 simplex connections are required to pack four incoming di-bits into an outgoing byte.
n
From
stream a, time slot n. Connection memory subrate field = 0100X11.
n
From
stream b, time slot n + 1. Connection memory subrate field = 0100X01.
n
From
stream c, time slot n + 2. Connection memory subrate field = 0101X00.
n
From
stream d, time slot n + 3. Connection memory subrate field = 0110X10.
n
To
stream e, time slot n + 10. Connection memory subrate field is don’t care.
Figure 51. Subrate Switching Example, Byte Packing
14.2.2.3.4 Subrate Unpacking of Incoming Bytes
Because the H1x0 bus and the local stream bus are based on byte-oriented TDM data streams, and the T8110
architecture is geared towards standard byte switching, it is not possible to simultaneously switch subrate portions
of a single byte to different places. This limitation is overcome by application. To gain access to each subrate piece
contained in one incoming byte, that byte must be broadcast onto additional channels, one channel for each sub-
rate piece required. The means of broadcasting is up to the application—either the source device of the packed
subrate byte can broadcast it, or the device receiving that byte can broadcast it over unused channels and loop the
broadcast bytes back in. The example from Figure 51 is extended in Figure 52. This example shows the unpacking
of the packed byte created in Figure 51, output to four different channels.
FRAME (8 KHz)
TIMESLOT
STREAM a, DI-BIT CHANNELS IN
STREAM b, DI-BIT CHANNELS IN
STREAM c, DI-BIT CHANNELS IN
BIT POSTITIONS OF DI-BITS
WITHIN THE DATA BYTE
STREAM d, DI-BIT CHANNELS IN
STREAM e, DI-BIT CHANNELS OUT
n
n + 1
n + 2
n + 3
TIMESLOT
n + 10
7:
6
5:
4
3:
2
1:
0
a
1
a
2
a
3
a
4
b
1
b
2
b
3
b
4
a
4
d
2
b
4
c
3
c
1
c
2
c
3
c
4
d
1
d
2
d
3
d
4
7:
6
5:
4
3:
2
1:
0
7:
6
5:
4
3:
2
1:
0
7:
6
5:
4
3:
2
1:
0
7:
6
5:
4
3:
2
1:
0