S9712 指定端口被discarding

发布时间:  2016-06-29 浏览次数:  111 下载次数:  0
问题描述

S9712----S3700

S9700 V200R007C00SPC500     S3700 V100R006C05  

S9712与S3700通过电口直连,S97为根桥,S97的互连端口被discarding,无环形组网

S9712关键配置及接口状态如下:

#
stp instance 0 root primary
#
interface GigabitEthernet2/4/0/37
port link-type trunk
port trunk allow-pass vlan 1000
#

----[Port132(GigabitEthernet2/4/0/37)][DISCARDING]----
Port Protocol       :Enabled
Port Role           :Designated Port
Port Priority       :128
Port Cost(Dot1T )   :Config=auto / Active=20000
Designated Bridge/Port   :0.4846-fb87-3250 / 128.132
Port Edged          :Config=default / Active=disabled
Point-to-point      :Config=auto / Active=true
Transit Limit       :6 packets/s
Protection Type     :None
Port STP Mode       :MSTP
Port Protocol Type  :Config=auto / Active=dot1s
BPDU Encapsulation  :Config=stp / Active=stp
PortTimes           :Hello 2s MaxAge 20s FwDly 15s RemHop 20
TC or TCN send      :0
TC or TCN received  :0
BPDU Sent           :169      

S3700关键配置及接口状态如下:

#
stp bpdu-protection
#
interface Ethernet0/0/1
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 1000
bpdu disable
dhcp snooping trusted
#

----[Port3(Ethernet0/0/1)][FORWARDING]----
Port Protocol       :Enabled
Port Role           :Designated Port
Port Priority       :128
Port Cost(Dot1T )   :Config=auto / Active=199999
Designated Bridge/Port   :32768.80fb-06b0-a03e / 128.3
Port Edged          :Config=enabled / Active=enabled
BPDU-Protection     :Enabled
Point-to-point      :Config=auto / Active=true
Transit Limit       :147 packets/hello-time
Protection Type     :None
Port STP Mode       :MSTP
Port Protocol Type  :Config=auto / Active=dot1s
PortTimes           :Hello 2s MaxAge 20s FwDly 15s RemHop 20
TC or TCN send      :0
TC or TCN received  :0
BPDU Sent           :1110            


处理过程

1、正常情况,如存在环路,应该是备份端口被阻塞,指定端口肯定不会被阻塞的,根据stp原理,指定端口除非收到优先级更高的bpdu报文,状态会改变,可能会被阻塞,在S97上debug stp发现,收到S37过来的bpdu,其Root id为S37自己,而且一直都是,确认问题根因在S37上:

<NeiWang-S9712-CSS>
Jun 23 2016 15:49:20.530.1 NeiWang-S9712-CSS MSTP/7/PKT:
Port132(GigabitEthernet2/4/0/37) Rcvd Packet(Length: 102)
ProtocolVersionID               : 03
BPDUType                        : 02
Flags                           : 7c( DESIGNATED  Learning  Forwarding  Agreement )
CIST Root Identifier            : 32768.80fb-06b0-a03e
CIST External Path Cost         : 0
CIST Bridge Identifier          : 32768.80fb-06b0-a03e
CIST Port Identifier            : 128.2
Message Age                     : 0
Max Age                         : 20
Hello Time                      : 2
Forward Delay                   : 15
Version 1 Length                : 0
Version 3 Length                : 64
CIST Regional Root Identifier   : 32768.80fb-06b0-a03e
CIST Internal Root Path Cost    : 0
CIST Remaining Hops             : 20.

2、查看配置发现,S37上所有端口都bpdu disable,导致无法处理收到的bpdu报文,一直认为自己为根桥,发送的bpdu报文异常,开启S3700的接口bpdu enable后问题解决

根因
S3700端口bpdu disable,导致无法处理收到的bpdu报文,一直认为自己为主
解决方案
开启S3700的接口bpdu enable,开启后问题解决
建议与总结
stp的交互报文为bpdu报文,请注意

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