我们已将旧的 3750 交换机替换为 WS-C3850-24T(堆叠模式下数量:2)。每当我插入任何 SFP 模块来连接我们不同的部门时,所有端口都会变成琥珀色几秒钟,在此期间,其他端口的所有其他连接都会断开,几秒钟后,所有端口都会恢复绿色并恢复连接。这在旧的 3750 交换机上从未发生过。可能的原因是什么?
以下是 STP 详细信息。
xxx-NOC-3850-Cluster#show spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: none
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
EtherChannel misconfig guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 0 0 0 28 28
---------------------- -------- --------- -------- ---------- ----------
1 vlan 0 0 0 28 28
以下是库存输出:
XXX-NOC-3850-Cluster#sh inv
NAME: "c38xx Stack", DESCR: "c38xx Stack"
PID: WS-C3850-24T , VID: V07 , SN: FOC2126L0T1
NAME: "Switch 1", DESCR: "WS-C3850-24T-S"
PID: WS-C3850-24T-S , VID: V07 , SN: FOC2126L0T1
NAME: "StackPort1/1", DESCR: "StackPort1/1"
PID: STACK-T1-50CM , VID: V01 , SN: MOC2102A2VN
NAME: "Switch 1 - Power Supply B", DESCR: "Switch 1 - Power Supply B"
PID: PWR-C1-350WAC , VID: V02 , SN: LIT20462TNP
NAME: "Switch 1 FRU Uplink Module 1", DESCR: "4x1G Uplink Module"
PID: C3850-NM-4-1G , VID: V01 , SN: FOC21083GDN
NAME: "GigabitEthernet1/1/1", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: FNS12060A5K
NAME: "GigabitEthernet1/1/4", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: FNS17041183
NAME: "Switch 2", DESCR: "WS-C3850-24T-S"
PID: WS-C3850-24T-S , VID: V07 , SN: FCW2113C1AK
NAME: "StackPort2/1", DESCR: "StackPort2/1"
PID: STACK-T1-50CM , VID: V01 , SN: MOC2102A2VN
NAME: "Switch 2 - Power Supply B", DESCR: "Switch 2 - Power Supply B"
PID: PWR-C1-350WAC , VID: V02 , SN: ART2205FCLN
NAME: "Switch 2 FRU Uplink Module 1", DESCR: "4x1G Uplink Module"
PID: C3850-NM-4-1G , VID: V01 , SN: FOC21065HC4
NAME: "GigabitEthernet2/1/1", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: FNS17041321
NAME: "GigabitEthernet2/1/4", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: FNS17041205
答案1
如果您的用户端口未处于端口快速模式(默认情况下如所示Portfast Default is disabled
,或每个端口),那么当生成树收敛时,您将遇到中断。
建议按如下方式设置用户端口,以尽量减少 STP 的影响:
switchport mode access
switchport access vlan ###
spanning-tree portfast
如果您不想在每个接口上输入,那么您可以在全局配置模式下spanning-tree portfast
将所有访问端口设置为 portfast 模式。spanning-tree portfast default
也不建议使用 Vlan 1,因为它通常未标记且由 Cisco 用于值得与用户流量分离的网络管理功能。