Wireless group complaint that there is packet loss (ip path alarm) on NodeB and RNC link. The transmission is using EPLAN service on OSN 3500 optical network. When performing Ethernet BERT test using Test Gear, the result is normally pass. However, throughput test (RFC2544) fails when testing the required capacity. For example, if 4 E1 (VC-12) is configured, throughput is set at 8MB and the test fails.
T2000 shows no alarms on the link. Ethernet Test on VCTRUNK using T2000 also passed i.e. Transmit and receive counter frames are same.
1. Configure Hub/ Spoke setting on each EPLAN service (VB ID) to separate the communication flow between each VCTRUNK and PORTS. Refer to T2000 help file on how to configure this setting. (Screenshot attached)
2. Avoid any physical loopback (Layer 1 loopback) on Ethernet port in EPLAN network.
3. Always set VLAN ID FILTERING for each EPLAN network. Omit VLANID=1 in VLAN filtering table if the network uses specific VLAN tag.
4. Enable RSTP setting to control broadcast packets in EGS board.
EFS and EGS board doesn’t support huge network equipments on EPLAN network. This problem only happens on larger network, for example on 3G network consisting of hundreds of NodeB and other network equipments. Huge network on EPLAN causes broadcast storm on the LAN network thus resulting packet loss on data transmission.
Instead of using EPLAN network, large 3G transmission network should use EPL service as the communication flow is always Unicast from NodeB to RNC. Huge EPLAN network can cause broadcast storm on the Ethernet board resulting data packet loss.