C2 Byte And Scrambling - Cisco ONS 15454 Software Feature And Configuration Manual

POS on the ML-Series card

C2 Byte and Scrambling

As listed in
ATM-style scrambling is enabled or not. RFC 2615, which defines PPP over SONET, mandates the use
of these values based on the scrambling setting. The RFC defines the C2 byte values as follows: "the
value of 22 (16 hex) is used to indicate PPP with X^43+ 1 scrambling [4]. For compatibility with
RFC 1619 (STS-3c-SPE/VC-4 only), if scrambling has been configured to be off, then the value 207 (CF
hex) is used for the Path Signal Label to indicate PPP without scrambling."
In other words:
•
•
•
Most POS interfaces that use a default C2 value of 0x16 (22 decimal) insert the pos flag c2 22 command
in the configuration, although this line does not appear in the running configuration since it is the default.
Use the pos flag c2 command to change the value from its default, as follows:
Router(config-if)# pos flag c2 ?
<0-255>
Changing the C2 value from the default value does not affect POS scrambling settings.
Note
Use the show run command to confirm your change. The show controller pos command outputs the
receive and transmit values and the C2 value. Thus, changing the value on the local end will not change
the value in the show controller command output.
Router# sh controllers pos 0
Interface POS0
Hardware is Packet/Ethernet over Sonet
PATH
PAIS
PPLM
BER_SF_B3 = 0
NEWPTR
Active Alarms : None
Demoted Alarms: None
Active Defects: None
Alarms reportable to TCC/CLI: PAIS PRDI PLOP PUNEQ PPLM PTIM PPDI BER_SF_B3 BER_
SD_B3
Link state change defects: PAIS PLOP PRDI PPDI BER_SF_B3
Link state change time
DOS FPGA channel number: 0
Starting STS (0 based) : 0
Circuit size
RDI Mode
C2 (tx / rx)
Framing
Path Trace
Mode
Buffer
Remote hostname :
Remote interface:
Remote IP addr
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
4-10
Table 4-2, POS interfaces use a value of 0x16 or 0xCF in the C2 byte depending on whether
If scrambling is enabled, POS interfaces use a C2 value of 0x16 (PPP and HDLC encapsulation).
If scrambling is disabled, POS interfaces use a C2 value of 0xCF (PPP and HDLC encapsulation).
LEX encapsulation uses a C2 value of 0x01 regardless of the scrambling setting.
byte value, default 0x16
= 0 PLOP
= 0 PUNEQ
BER_SD_B3 = 0
= 0 PSE
: 200 (msec)
: STS-24c
: 1 bit
: 0x01 / 0x01
: SONET
: off
: Unstable
:
= 0 PRDI = 0
= 0 PPDI = 0
BIP(B3) = 14
= 0 NSE = 0
Chapter 4 Configuring Interfaces
PTIM = 0
REI = 155
78-15224-02