System information

Configuring Packet Over SONET
14-13
Defining SONET Frame Overhead Bytes
SONET overhead bytes identify information in the SONET frame. Refer to the
GR-253-CORE document for STS Path Signal Label Assignments and the
hexadecimal values required for the SONET frame overhead bytes.
Follow these steps to specify flags for the SONET frame overhead bytes:
1. The c2 byte of the SONET frame is a path signal identifier. To set the
hexadecimal value for the c2 byte, use the pos flag c2 command in Interface
Configuration mode, as shown below:
MOT(config-if)#pos flag c2 <hexnum>
where:
hexnum is the hexadecimal value for the c2 byte.
For example:
• PPP encapsulation is 0xCF
• HDLC encapsulation is 0x16
• ATM encapsulation is 0x13
• Unequipped is 0x00
• Equipped non-specific is 0x01
2. The c2 byte is the path signal label expected from the far end SONET equipment.
To set the hexadecimal value for the c2 byte for the SONET frame payload for the
PPP or HDLC protocols, use the pos flag c2-exp command in Interface
Configuration mode as shown below:
MOT(config-if)#pos flag c2-exp <hexnum>
where:
hexnum is the hexadecimal value for the c2 byte.
3. If the received c2 byte differs from the expected c2 byte, a payload mismatch
occurs. To view a payload mismatch for the c2 byte, use the show controllers pos
command in Interface Configuration mode, as shown below:
MOT(config-if)#show controllers pos