Dear admin,One day I found that The Gb Link of SGSN was not working & I got the alarm that NSVL Faulty.I checked from my point of view but did not get my answer. Then I put the details to Huawei support website for their investigation.I am so happy to say that I received my clear answer within shortest possible time from Huawei support website.Solution:1. We checked the physical link between the BSC6000 and SGSN by pinging the IP address of the SGSN from BSC6000 by executing the command given below:PING IP: SRN=0, SN=14, DESTIP="10.124.76.4";The ping was OK, so we concluded the link was also OK at physical layer.2. We checked the GFGUG board, the board was working normally.3. We checked the data configuration at the BSC6000 end and the SGSN end, it was correct.4. When we tried to ping the SGSN by using the source IP as the device IP of GFGUG we were getting request timed out. The command we used was as given below:PING IP: SRN=0, SN=14, DESTIP="10.124.76.4", SRCIP="10.118.229.1";5. Similarly we were able to ping the physical port IP of the GFGUG from the SGSN side but we were not able to ping the logical IP of the PCU.6. When we checked the routes added in the NE-40 we found that in NE-40-1 the route added to the logical IP of PCU (10.118.229.1) contained the active physical port IP (10.118.232.130) as the first hop and in NE-40-2 the route to the logical IP (10.118.229.1) contained the standby physical port IP (10.118.232.131) as the first hop.7. Since the current active router was NE-40-2 it was trying to route all the packets sent from SGSN to PCU logical IP through 10.118.232.131. But in BSC6000 irrespective of the board no. the active IP is always taken by the current active board i.e for eg. if the GFGUG boards are configured in slots 14 and 15 then the active IP will always be given to the board which is currently active i.e. if 14 is active it will have the IP 10.118.232.130 and 15 will have the IP 10.118.232.131 and vice versa.8. Since NE-40-2 was active whenever it tried to send packets to the PCU through 10.118.232.131 the packets could not reach the PCU since this was the IP of the physical port of standby board and hence the Gb link was comming faulty.9. Once we added the route to logical IP of PCU (10.118.229.1) via the active physical port IP(10.118.232.130) in NE-40-2 the Gb link was up. Thanks to Huawei team