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Test Frames Cannot Be Transferred During the EPL Service Interconnection Between the OSN EMS4 Board and the Metro1000V3 EFS Board

Publication Date:  2012-07-25 Views:  47 Downloads:  0
Issue Description
During the EPL service interconnection between the EMS4 board of the OSN and the EFS board of the Metro1000V3, test frames cannot be transferred when the VCTRUNK ports of the data boards are set to Tag but can be transferred when the VCTRUNK ports of the data boards are set to Access. The services, however, are actually normal in both cases.
EMS4 version: 4.13 EFS version: 2.21 
 
Alarm Information
Null
Handling Process
1. The EFS board of version 2.21 supports only the MAC bearing mode of test frames.
2. The EMS4 board of version 4.13 supports both the MAC bearing mode and the GFP bearing mode of test frames.
3. The test frames sent by the EFS board in MAC bearing mode do not carry VLAN data, that is, these data packets do not carry the VLAN tag when they are transmitted on lines. And the EFS board doesn't identifies whether the received test frames carry VLAN or not. Therefore, the test frames can be transferred when the VCTRUNK ports of both the receiving board and the transmitting board are set as tagged ports. This has been proven by lab tests.
4. The EMS4 board can receive both test frames in MAC bearing mode and test frames in GFP bearing mode. After receiving a test frame in MAC bearing mode, however, the EMS4 board identifies whether the test frame carries VLAN data.
5. During the service interconnection between the EMS4 board and the EFS board, the EMS4 board sends test frame in both MAC bearing mode and GFP bearing mode. When the test frame reaches the EFS board, however, the EFS board can receive only the test frame in MAC bearing mode and responds with a test frame also in MAC bearing mode. The response MAC frame does not carry VLAN data. After the response MAC frame reaches the EMS4 board, the EMS4 board identifies whether the response MAC frame carries VLAN data. If the response MAC frame does not carry VLAN data, the tagged port of the EMS4 board discards the response MAC frame whereas the access port of the EMS4 board permits the response MAC frame to enter the EMS4 board. 
 
Root Cause
1. The EFS board’s bearing mode of test frames is different from the EMS4 board’s bearing mode of test frames.
2. The EFS board’s mode of identifying test frames is different from the EMS4 board’s mode of identifying test frames. 
 
Suggestions
1. Upgrade the EFS board of the Metro1000V3 to version 2.42, so that the EFS board supports both test frames in MAC bearing mode and test frames in GFP bearing mode.
2. The fault occurs to all the early versions of the EFS board that support only test frames in MAC bearing mode. Therefore, upgrade the version of the FES board to a version that supports both test frames in MAC bearing mode and test frames in GFP bearing mode.
3. This fault does not occur when the EMS4 board is interconnected with the EFT board, because the EFT board supports only test frames in GFP bearing mode. 
 

END