
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
Preliminary Data Sheet, Rev. 1
October 2000
262
Lucent Technologies Inc.
VT/TU Mapper Functional Description
(continued)
Receive Lower-Order Path Overhead (RX_LOPOH)
The RX_LOPOH logic block (in Figure 31 on page 248) will perform all necessary functions to store and transmit
the overhead associated with each VT/TU, specifically, V5, J2, Z6/N2, Z7/K4, and the O bits. The following features
will be implemented:
I
V5, J2, Z6/N2, Z7/K4, and the 0 bits, on a per VT basis, are stored for one complete superframe and transmitted
during the next superframe. REI and RDI values received from the SPEMPR and TMUX are stored on a per-
frame basis and transmitted during the next frame. REI and RDI values are latched during the A1 time of the of
the received SONET frame.
I
When operating in UPSR mode (bit VT_UPSR = 1 (Table 173)), REI, RDI, and ERDI values in the V5 and Z7
bytes will be modified based on the receive status. See Table 153 on page 267 for automatic generation require-
ments.
I
The REI and RDI received from the SPEMPR and TMUX blocks is the first data type transmitted in each frame
as a burst of 34 bits on the rising edge of the SPE mapper Rx clock (6.48 MHz). All other data types are transmit-
ted as a burst of 224 bits on the rising edge of the SPE mapper Rx clock.
Note:
The number of valid bits transmitted is dependent upon the VT/TU group types. i.e., full VT2 equals 168 bits.
I
The first frame of the four frame multiframe contains data types 001, 010, 011, and 100, respectively. The second
frame of the multiframe contains data types 001, 101, and 110, respectively. The remaining frames contain only
data type 001. Data type headers will be defined as shown in Table 149 below.
All data types must be transmitted within 500 μs.
Table 149. Data Type Header Definitions
* All overhead bytes will be transmitted from MSB to LSB.
O bits are received in the byte following J2 and the byte following Z6/N2 in asynchronous mode. The O bits will be transmitted in the order of
which they are received within a VT, starting with the MSB of the nibble following the J2 byte.
Figure 37, VT Mapper Receive Path Overhead Serial Access Channel on page 281, contains the RX_LOPOH
block serial channel format and timing.
Header
0
0
1
1
0
0
1
1
Description
0
0
0
0
1
1
1
1
0
1
0
1
0
1
0
1
Reserved.
TMUX and SPE mapper RDI/REI.
V5 byte, 28/21 bytes starting with VT 1*.
J2 byte, 28/21 bytes starting with VT 1.
Z6/N2 byte, 28/21 bytes starting with VT 1.
Z7/K4 byte, 28/21 bytes starting with VT 1.
O bits, 28/21 bytes starting with VT 1.
Reserved. Data will be ignored.