How The Ctp Implementation Of Tdm/Tdc Works - Juniper CTP Series Manual

Using Bundles to Create Logical Configurations for Physical Interfaces, CTP Release 7.3, CTPView Release 7.3
No TDM

How the CTP Implementation of TDM/TDC Works

18
Figure 8: Serial Port Bit Allocation Without TDM
31 30 29 28 27 26 25 24 23 22
D D D D D D D D D D D D D D D D
When you enable TDM, a specific number of the 32 data bits are allocated for another
function. That is, another function is interleaved with the serial data. For example, in
Figure 9 on page 18 half of the bits (16 bits in 32) are allocated to serial port data (as
indicated by D), and half of the bits are allocated to TDM (as indicated by T).
Figure 9: Serial Port Bit Allocation With 16 Bits Allocated to TDM
15 14 13 12 11
D T D T D T D T D T
TDM Rate 16 (1:1)
The number of bits out of 32 that are allocated to TDM is called the TDM rate.
Figure 9 on page 18 showed a TDM rate of 16.
for TDM rates of 2, 4, and 8.
Figure 10: Bit Allocation for TDM Rates of 2, 4, and 8
29 28 27 26 25 24 23 22 21 20
D D D D D D D D D D D D D D D
TDM Rate 2 (15:1)
27 26 25 24 23 22 21 20 19 18
D D D D D D D T D D D D D D D
TDM Rate 4 (7:1)
23 22 21 20 19 18 17 16
D D D T D D D T D D D
TDM Rate 8 (3:1)
To use this feature, you configure two bundles on each CTP device:
A high-speed bundle that carries all traffic by interleaving multiple data sources into
a single stream.
A low-speed bundle that routes clock and data signals.
The high-speed bundle oversamples the incoming clock (TT) and data (SD) from the
low-speed bundle. At the remote end of the network, the embedded circuit data is
recovered and exits the node on the low-speed bundle as RT and RD outputs. The direct
interleaving of two bundles' data allows TDC to be maintained between the two bundles
with an accuracy of one bit time at the bundle's data rate.
21 20 19 18 17 16 15 14 13 12
D D D D D D D D D D D D D D D D
10 9 8 7 6
D T D T D T D T D T
Figure 10 on page 18
19 18 17 16 15 14 13 12 11 10
T D D D D D D D D D D D D D D D
17 16 15 14 13 12 11 10
T D D D D D D D
15 14 13 12 11 10 9
T D D D T D D D T
11 10 9 8 7 6 5 4 3 2
5 4 3 2 1
D T D T D T D T D T
shows the bit allocation
9 8 7 6 5 4 3 2 1
9 8 7 6 5 4 3 2 1
T D D D D D D D
8 7 6 5 4 3 2 1
D D D T D D D T D D D
Copyright © 2018, Juniper Networks, Inc.
1 0
0
D T
0
T
0
T
0
T