HP HSR6800 Configuration Manual page 62

As shown in Figure 7, when the AU-4 path is used, the multiplexing structure for 2 Mbps is 3-7-3. The
formula for calculating the TU- 1 2 sequence numbers of different locations in the same VC-4 is as follows:
Sequence number of TU- 1 2 = TUG-3 number + (TUG-2 number – 1) x 3 + (TU- 1 2 Number – 1) x 21
The two TU- 1 2s are adjacent to each other if they have the same TUG-3 number and TUG-2 number but
different TU- 1 2 numbers with a difference of 1.
The numbers in the formula mentioned refer to the location numbers in a VC-4 frame. TUG-3 can be
numbered in the range of 1 to 3; TUG-2 in the range of 1 to 7 and TU- 1 2 in the range of 1 to 3. TU- 1 2
numbers indicate the order (E1 channel number) in which the 63 TU- 1 2s in a VC-4 frame are multiplexed.
Figure 11 Order of TUG-3s, TUG-2s, and TU-12s in a VC-4 frame
1
VC-4 TUG-3
2
TUG-3
3
TUG-3
You can calculate TU- 1 2 numbers in the same way when the AU-3 path is used.
When 63 E1 channels or 84 T1 channels are configured on a CPOS interface, you can reference E1 or
T1 channels by referencing the numbers in the range of 1 to 63 or 1 to 84. When connecting your device
to channelized STM- 1 interfaces on devices of other vendors, you should consider the possible
numbering differences due to different channel referencing methods.
Figure 12 Order of TUG-3, VC-3, and C-3 in a VC-4 frame
The channel number calculation for E3/T3 channels is simpler than that for E1/T1 channels. As shown
in Figure 12, when the AU-4 multiplexing path is used, as TUG-3 and VC-3 are not divided into
lower-order paths, the E3/T3 channel numbers are the TUG-3 numbers. When the AU-3 multiplexing
path is used, you can get the E3/T3 channel numbers in the same way.
TU-12
1
TUG-2 TU-12
TU-12
TU-12
2
TUG-2 TU-12
.
TU-12
.
.
TU-12
7
TUG-2
TU-12
TU-12
57
1
2
3
1
2
3
1
2
3