<提要> 小白是某金代的工程师，一天接了个小case，部署一个新站点；
<方案> 一个router做GW，三个switch做二层接入；
<问题> PC死活ping不通GW，万恶的 "....."
<结论> 大家觉得是哪个方案更靠谱？
A: 重配
B: 插拔网线
C: Reload
D: 开case让TAC去头痛吧~
E: 灵异事件~
【TAC结论】
在一些特殊的情况下，STP的软件和硬件端口状态不同步，软件显示forwarding，但是实际上硬件确是block的~
【Process】
- Identify the MVID (VLAN TO IIF ID MAPPING)
- Identify the IIF-ID associated to an interface
- Identify the ASIC Number/ASIC Port
- Read the ilemststatetable(Register) to identify if they are Forwarding/Blocking
===== SPANNING_TREE STATE IN SOFTWARE: =========
======= Identify the MVID (VLAN TO IIF ID MAPPING) ========
MVID: 4
======= Identify the IIF-ID associated to an interface ========
BGL.S.09-3850-1#sh platform port-asic ifm interfaces ethernet sw 1
Interface Table
Interface IIF-ID State Additional Details
Gi1/0/1 0x00c23a0000000008 READY
Gi1/0/47 0x00c19e8000000069 READY
======= Identify the ASIC Number/ASIC Port ==========
Interface Name: Gi1/0/1
ASIC Number: 1
ASIC Port:21
BGL.S.09-3850-1#sh platform port-asic ifm iif-id 0x00c19e8000000069
Interface Table
Interface IIF-ID : 0x00c19e8000000069
Interface Name : Gi1/0/47
Interface Block Pointer : 0x5666a9d0
Interface State : READY
Interface Stauts : IFM-ADD-RCVD, FFM-ADD-RCVD
Interface Ref-Cnt : 6
Interface Epoch : 0
Interface Type : ETHER
Port Type : SWITCH PORT
Port Location : LOCAL
Slot : 1
Unit : 47
Slot Unit : 47
SNMP IF Index : 49
GPN : 47
EC Channel : 0
EC Index : 0
ASIC : 0
ASIC Port : 19
Port LE Handle : 0x56188694
Non Zero Feature Ref Counts
FID : 48(AL_FID_L2_PM), Ref Count : 1
FID : 77(AL_FID_STATS), Ref Count : 1
FID : 51(AL_FID_L2_MATM), Ref Count : 1
FID : 13(AL_FID_SC), Ref Count : 1
FID : 26(AL_FID_QOS), Ref Count : 1
Sub block information
FID : 48(AL_FID_L2_PM), Private Data : 0x56684fe4
FID : 26(AL_FID_QOS), Private Data : 0x5666aab0
Gi1/0/47
========
ASIC number:0
ASIC Port:19
======== Read the ilemststatetable(Register) to identify if they are Forwarding/Blocking =========
If MVID is 4 then use ilemststatetable-3 (Because the value starts with 0 )
If MVID is 5 then use ilemststatetable-4
blkFwd31to0 0xffffffff --->Convert this into binary (1111 1111 1111 1111 1111 1111 1111 1111)
If the bit is set to 1 then it is blocking state
If the bit is set to 0 then it is forwarding state
ASIC Port Number 19 so check the 19th bit and it is set to 1 hence it is in blocking state
Gi1/0/1
=======
ASIC number:1
ASIC Port:21
blkFwd31to0 0xffcfffff --->Convert this into binary (1111 1111 1100 1111 1111 1111 1111 1111)
ASIC
Port Number is 21 so check the 21st bit and it is set to 0 hence it is
in forwarding state.
