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Cisco ONS 15454 Reference Manual, R8.5.x
78-18106-01
Chapter 11 Circuits and Tunnels
11.14 Path Signal Label, C2 Byte
(LLC)/Subnetwork Access Protocol (SNAP) header fields on an Ethernet network; it allows a single
interface to transport multiple payload types simultaneously. C2 byte hex values are provided in
Table 11-10.
If a circuit is provisioned using a terminating card, the terminating card provides the C2 byte. A VT
circuit is terminated at the XCVT, XC10G, or XC-VXC-10G card, which generates the C2 byte (0x02)
downstream to the STS terminating cards. The XCVT, XC10G, or XC-VXC-10G card generates the C2
value (0x02) to the DS1 or DS3XM terminating card. If an optical circuit is created with no terminating
cards, the test equipment must supply the path overhead in terminating mode. If the test equipment is in
pass-through mode, the C2 values usually change rapidly between 0x00 and 0 xFF. Adding a terminating
card to an optical circuit usually fixes a circuit having C2 byte pro blems. Table 11-11 lists label
assignments for signals with payload defects.
Table 11-10 STS Path Signal Label Assignments for Signals
Hex Code Content of the STS Synchronous Payload Envelope (SPE)
0x00 Unequipped
0x01 Equipped - nonspecific payload
0x02 VT structured STS-1 (DS-1)
0x03 Locked VT mode
0x04 Asynchronous mapping for DS-3
0x12 Asynchronous mapping for DS4NA
0x13 Mapping for Asynchronous Transfer Mode (ATM)
0x14 Mapping for distributed queue dual bus (DQDB)
0x15 Asynchronous mapping for fiber distributed data interface (FDDI)
0x16 High-level data link control (HDLC) over SONET mapping
0x1B Generic Frame Procedure (GFP) used by the FC_MR-4 and ML
Series cards
0xFD Reserved
0xFE 0.181 test signal (TSS1 to TSS3) mapping SDH network
0xFF Alarm indication signal, path (AIS-P)
Table 11-11 STS Path Signal Label Assignments for Signals with Payload Defects
Hex Code Content of the STS SPE
0xE1 VT-structured STS-1 SPE with 1 VTx payload defect (STS-1 with 1 VTx PD)
0xE2 STS-1 with 2 VTx PDs
0xE3 STS-1 with 3 VTx PDs
0xE4 STS-1 with 4 VTx PDs
0xE5 STS-1 with 5 VTx PDs
0xE6 STS-1 with 6 VTx PDs
0xE7 STS-1 with 7 VTx PDs
0xE8 STS-1 with 8 VTx PDs
0xE9 STS-1 with 9 VTx PDs