During the connection of NE40E and NE80E POS interfaces between different sites the interfaces fail to go to UP/UP state and LOP alarm is generated on the interface. The transmission equipment in this case is Ericsson ADM (Marconi)
[NE80E-01-Pos1/1/1]disp this inter
Pos1/1/1 current state : UP
Line protocol current state : DOWN
Route Port,The Maximum Transmit Unit is 4470, Hold timer is 10(sec)
Internet Address is 10.193.250.5/30
Link layer protocol is PPP
The Vendor PN is FTLF1323P1BTR-HW
Port BW: 155M, Transceiver max BW: 155M, Transceiver Mode: SingleMode
WaveLengh: 1310nm, Transmission Distance: 15km
Tx optical power: -11.75dBm, Rx optical power: -10.65dBm
Physical layer is Packet Over SDH
Scramble enabled, clock master, CRC-32, loopback: none
Flag J0 "NetEngine "
Flag J1 "NetEngine "
Flag C2 22(0x16)
section layer: none
line layer: none
path layer: LOP PRDI
section layer: B1 74655
line layer: B2 86117 REI 40020
path layer: B3 26566 REI 14168
Statistics last cleared:never
Last 300 seconds input rate 8 bits/sec, 0 packets/sec
Last 300 seconds output rate 24 bits/sec, 0 packets/sec
Input: 372 packets, 6944 bytes
Input error: 2427 shortpacket, 0 longpacket, 433 CRC, 1751 lostpacket
Output: 1072 packets, 23686 bytes
Output error: 0 lostpackets
Output error: 0 overrunpackets, 0 underrunpackets
LOP alarm is usually generated by transmission equipment in case of mismatching SDH framing (using SDH with SONET). However since both equipment were configured for SDH framing this alarm should not be present.
After receiving a frame, the transmission device of any early version on the current network checks the SS bit (2 bits in total) in the H1H2 overhead byte of the frame. The SS bit of an SDH frame should be 10 and of an SONET frame should be 00. If the SS bit of the frame is not the same as the expected value, the frame cannot be forwarded.
The ITU-T standard released in 2007 states that since the 2000 version, the SS bit has been deleted from the AU-n pointer detection algorithm of ITU-T G.783 and G.806. The specification on the SS bit only exists in versions earlier than 2000 .The ATM or POS FPIC on the NE40E&80E LPUF-10 or LPUF-20/21 adopts a chip manufactured after the year of 2000, which has no specification on the SS bit and adopts the default value 00. The transmission device, however, adopts a strict mechanism to check the SS bit of every received frame. As a result, when the NE40E&80E is connected to the transmission device through the ATM or POS interface in SDH mode, the link layer protocol fails to go Up and the SDH frame cannot be forwarded.
So solve this issue set the parameter of the SS bit on the transmission equipment to (ignore SS bit).