C2 Byte; Figure 4-1 Three Sonet Layers; Table 4-2 C2 Byte Common Values - Cisco ONS 15454 Software Feature And Configuration Manual

Chapter 4 Configuring Interfaces
Figure 4-1
9 Rows

C2 Byte

One of the overhead bytes in the SONET frame is the C2 Byte. The SONET standard defines the C2 byte
as the path signal label. The purpose of this byte is to communicate the payload type being encapsulated
by the SONET framing overhead (FOH). The C2 byte functions similarly to EtherType and Logical Link
Control (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
Table 4-2
Hex Value
00
01
02
03
04
12
13
14
15
16
CF
FE
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
78-15224-02
Three SONET Layers
3 Bytes
STS
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4-2.
C2 Byte Common Values
SONET Payload Contents
Unequipped
Equipped non specific payload
Virtual Tributaries (VTs) inside (default)
VTs in locked mode (no longer supported)
Asynchronous DS3 mapping
Asynchronous DS-4NA mapping
Asynchronous Transfer Mode (ATM) cell mapping
Distributed Queue Dual Bus (DQDB) protocol cell mapping
Asynchronous Fiber Distributed Data Interface (FDDI) mapping
IP inside PPP with scrambling
IP inside PPP without scrambling
Test signal mapping (see ITU-T G.707)
B7 Byte
Payload
Capacity
Payload Envelope
POS on the ML-Series card
4-9