关于pos接口下C2字节导致单向环通的解释

spearhead

The value of the c2 byte is determined as follows: class="pSmartList1">
If the value of the c2 byte has not been explicitly configured with the pos flag command, the SONET framer sends the following values:
class="pSmartList2">
For Cisco HDLC encapsulation with or without SPE scrambling: 0xCF
For PPP encapsulation with scrambling: 0x16 (RFC 2615)
For PPP encapsulation without scrambling: 0xCF (RFC 2615)
If the value of the c2 byte has been explicitly configured with the pos flag command, the configured value is sent regardless of the encapsulation method.
The value of the s1s0 bits is determined as follows:

class="pSmartList1">
If the value of the s1s0 bits has not been explicitly configured with the pos flag command, the SONET framer sends the following values:
class="pSmartList2">
For SONET framing, the default value is 0.
For SDH framing, the default value is 2.
If the value of the s1s0 bits has been explicitly configured with the pos flag command, the configured value is used regardless of the framing.
以下是在Cisco 设备下 show controller pos后的信息

POS2/3/1
SECTION
LOF = 4          LOS    = 4                            BIP(B1) = 86366
LINE
AIS = 4          RDI    = 3          FEBE = 45406715   BIP(B2) = 17971784
PATH
AIS = 20         RDI    = 20         FEBE = 47535      BIP(B3) = 476240
PLM = 3          UNEQ   = 0          TIM = 0          TIU     = 0
LOP = 1          NEWPTR = 3552       PSE = 4449475    NSE     = 1

解释如下：

SECTION（再生段 RS 路由器跟本地阿卡设备互联之间）
LOF 帧丢失 = 4          LOS 无信号 = 4       BIP(B1) = 86366 因为LOF引起的
LINE（复用段 MS 路由器跟长话局骨干机房端口之间）
AIS = 4          RDI    = 3      FEBE 除去严重误码秒以外的误码= 45406715  

BIP(B2)收长话方向的B2误码 = 17971784
PATH（指段开销，VC4，全程通道）以下误码应该是收对端路由器的，与传输层面无关
AIS = 20 （）        RDI    = 20         FEBE = 47535      BIP(B3) = 476240
PLM = 3          UNEQ(C2 通道未装载)   = 0          TIM（J0踪迹字节） = 0   

     TIU     = 0
LOP 指针丢失，秒= 1          NEWPTR = 3552       PSE 指针增加个数，没有大的关

系 = 4449475    NSE 指针减少个数，没有大的关系    = 1