我遇到了一个非常奇怪的问题，希望有人能告诉我该去哪里找。我有一个新的 Netgear M4100-D10-POE 第 2 层管理型交换机，我们正在将其安装在一栋偏远的建筑中。它通过 CAT5 电缆连接到思科交换机，连接到我们网络的其余部分（我们有几个，它连接的位置似乎并不重要）。现在它工作正常，但是当我关闭这台 Netgear 交换机的电源（或将其从网络上拔下）时，我会收到一堆来自各种服务的电子邮件，表明一对其他思科交换机（Catalyst 3560 和 Catalyst 2960S）之间的网络连接丢失。这些交换机通过光纤线路相互连接。
奇怪的是，Netgear 交换机并未直接连接到发生链路故障的两台交换机中的任何一台。两者之间可能有 1 或 2 台其他 Cisco 交换机。我也没有在两台交换机上看到任何端口启动/关闭日志消息。我也知道这不是巧合，因为我可以随时通过插拔 Netgear 交换机重现该问题。
我唯一的猜测是它与 BGP、STP 或其他交换机到交换机协议有关，但我不知道如何监控它。
更新：以下是配置文件。首先是 Netgear 交换机：
!Current Configuration:
!
!System Description "M4100-D10-POE ProSafe 10-port FastEthernet L2+ Intelligent Edge PoE Desktop Managed Switch, 10.0.1.28, B1.0.0.9"
!System Software Version "10.0.1.28"
!System Up Time "2 days 23 hrs 58 mins 15 secs"
!Additional Packages QOS,IPv6 Management,Routing
!Current SNTP Synchronized Time: Mar 9 19:09:41 2015 UTC
!
network protocol none
network parms 172.16.112.68 255.255.240.0 172.16.112.4
vlan database
vlan 3-10,200
vlan name 3 "VOIP_HD"
vlan name 4 "CAMERA"
vlan name 5 "WIFI_MGMT"
vlan name 6 "WIFI_GUEST"
vlan name 7 "WIFI_DATA"
vlan name 8 "SAN_SATA"
vlan name 9 "SAN_SAS"
vlan name 10 "DMZ"
vlan name 200 "AUTOVOIP"
exit
ip ssh server enable
ip ssh protocol 2
no ip telnet server enable
configure
sntp server "172.16.112.6"
sntp server "0.north-america.pool.ntp.org" 2
sntp server "1.north-america.pool.ntp.org" 3
time-range
ip domain name "caymanport.com"
ip name server 172.16.112.6 172.16.112.23 172.16.112.9
snmptrap "CIPAread" ipaddr 172.16.112.65
voice vlan
no green-mode energy-detect
line console
no transport input telnet
exit
line telnet
exit
line ssh
exit
snmp-server sysname "CDCParts1Switch"
snmp-server location "CDC Taylor Parts Container"
snmp-server contact "IT Manager"
!
no snmp-server community public
no snmp-server community private
auto-voip vlan 200
interface 0/7
vlan participation include 2-3
vlan tagging 2-3
exit
interface 0/8
vlan participation include 2-3
vlan tagging 2-3
exit
interface 0/9
vlan participation include 2-10
vlan tagging 1-10
exit
interface 0/10
vlan participation include 2-10
vlan tagging 1-10
exit
no isdp run
no isdp advertise-v2
exit
现在Cisco 3560交换机（CDCVOIPSwitch）：
Current configuration : 19392 bytes
!
! Last configuration change at 11:31:57 EST Fri Mar 6 2015
! NVRAM config last updated at 15:35:31 EST Tue Mar 3 2015
!
version 12.2
no service pad
service timestamps debug uptime
service timestamps log datetime
service password-encryption
service sequence-numbers
!
hostname CDCVoipSwitch
!
boot-start-marker
boot-end-marker
!
aaa new-model
!
aaa session-id common
clock timezone EST -5
system mtu routing 1500
ip routing
ip domain-name caymanport.com
ip name-server 172.16.112.6
ip name-server 172.16.112.23
ip name-server 172.16.112.9
!
mls qos map cos-dscp 0 8 16 26 32 46 48 56
mls qos srr-queue input bandwidth 90 10
mls qos srr-queue input threshold 1 8 16
mls qos srr-queue input threshold 2 34 66
mls qos srr-queue input buffers 67 33
mls qos srr-queue input cos-map queue 1 threshold 2 1
mls qos srr-queue input cos-map queue 1 threshold 3 0
mls qos srr-queue input cos-map queue 2 threshold 1 2
mls qos srr-queue input cos-map queue 2 threshold 2 4 6 7
mls qos srr-queue input cos-map queue 2 threshold 3 3 5
mls qos srr-queue input dscp-map queue 1 threshold 2 9 10 11 12 13 14 15
mls qos srr-queue input dscp-map queue 1 threshold 3 0 1 2 3 4 5 6 7
mls qos srr-queue input dscp-map queue 1 threshold 3 32
mls qos srr-queue input dscp-map queue 2 threshold 1 16 17 18 19 20 21 22 23
mls qos srr-queue input dscp-map queue 2 threshold 2 33 34 35 36 37 38 39 48
mls qos srr-queue input dscp-map queue 2 threshold 2 49 50 51 52 53 54 55 56
mls qos srr-queue input dscp-map queue 2 threshold 2 57 58 59 60 61 62 63
mls qos srr-queue input dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31
mls qos srr-queue input dscp-map queue 2 threshold 3 40 41 42 43 44 45 46 47
mls qos srr-queue output cos-map queue 1 threshold 3 5
mls qos srr-queue output cos-map queue 2 threshold 3 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 2 4
mls qos srr-queue output cos-map queue 4 threshold 2 1
mls qos srr-queue output cos-map queue 4 threshold 3 0
mls qos srr-queue output dscp-map queue 1 threshold 3 40 41 42 43 44 45 46 47
mls qos srr-queue output dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31
mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue output dscp-map queue 3 threshold 3 16 17 18 19 20 21 22 23
mls qos srr-queue output dscp-map queue 3 threshold 3 32 33 34 35 36 37 38 39
mls qos srr-queue output dscp-map queue 4 threshold 1 8
mls qos srr-queue output dscp-map queue 4 threshold 2 9 10 11 12 13 14 15
mls qos srr-queue output dscp-map queue 4 threshold 3 0 1 2 3 4 5 6 7
mls qos queue-set output 1 threshold 1 138 138 92 138
mls qos queue-set output 1 threshold 2 138 138 92 400
mls qos queue-set output 1 threshold 3 36 77 100 318
mls qos queue-set output 1 threshold 4 20 50 67 400
mls qos queue-set output 2 threshold 1 149 149 100 149
mls qos queue-set output 2 threshold 2 118 118 100 235
mls qos queue-set output 2 threshold 3 41 68 100 272
mls qos queue-set output 2 threshold 4 42 72 100 242
mls qos queue-set output 1 buffers 10 10 26 54
mls qos queue-set output 2 buffers 16 6 17 61
mls qos
!
crypto pki trustpoint HTTPS_SS_CERT_KEYPAIR
enrollment selfsigned
serial-number
revocation-check none
rsakeypair HTTPS_SS_CERT_KEYPAIR
!
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
ip ssh time-out 60
ip ssh authentication-retries 2
!
interface FastEthernet0/1
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/2
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/3
description vip5312-3752
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/4
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/5
description vip5330-3757
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/6
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/7
description vip5330-3756
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/8
description vip5312-3759
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/9
description vip5330-3755
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/10
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/11
description vip5312-3758
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/12
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/13
description vip5330-3754
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/14
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/15
description vip5312-3732
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/16
description camCDCNetRm
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/17
description vip5312-3751
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/18
description vip5312-3760
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/19
description vip5312-3750
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/20
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/21
description vip5312-3761
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/22
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/23
description vip5312-3762
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/24
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/25
description vip5312-3763
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/26
switchport mode access
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/27
description vip5312-3764
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/28
description AP.Ware.Out.Corner
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/29
description vip5312-3765
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/30
description AP.Ware.Out.Center
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/31
description vip5312-3766
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/32
description WLC Port 2 (VL06)
switchport access vlan 6
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/33
description WLC Port 3 (VL07)
switchport access vlan 7
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/34
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/35
description vip5312-3753
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/36
description AP.Mech
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
spanning-tree portfast
!
interface FastEthernet0/37
description vip5312-3610
switchport mode access
switchport voice vlan 2
switchport port-security aging type inactivity
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
macro description cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
!
interface FastEthernet0/38
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/39
description WLC Port 4
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/40
description WLC Port 1 (VL05)
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
spanning-tree portfast
!
interface FastEthernet0/41
description AP.Warehouse02
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/42
description AP.Warehouse03
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/43
description AP.Warehouse01
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/44
description AP.CDC.Dwnstairs
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/45
description AP.CDC.Upstairs
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/46
description AP.CDCGuard
switchport trunk encapsulation dot1q
switchport trunk native vlan 5
switchport mode trunk
switchport voice vlan 2
spanning-tree portfast
!
interface FastEthernet0/47
description CDC-3300
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/48
spanning-tree portfast
!
interface GigabitEthernet0/1
description HDServerSwitch SM-
switchport trunk encapsulation dot1q
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust cos
auto qos voip trust
macro description cisco-switch
spanning-tree link-type point-to-point
!
interface GigabitEthernet0/2
description BillingVoipSwitch
switchport trunk encapsulation dot1q
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust cos
auto qos voip trust
macro description cisco-switch
spanning-tree link-type point-to-point
!
interface GigabitEthernet0/3
description CDCDelivSwitch MM Fiber
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/4
description CDCSwitch MM Fiber
switchport trunk encapsulation dot1q
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust cos
auto qos voip trust
macro description cisco-switch
spanning-tree link-type point-to-point
!
interface Vlan1
ip address 172.16.116.2 255.255.240.0
!
interface Vlan2
ip address 172.16.129.4 255.255.255.0
!
interface Vlan3
ip address 172.16.130.4 255.255.255.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.112.1
ip http server
ip http secure-server
!
line con 0
line vty 0 4
length 0
transport input ssh
line vty 5 15
transport input ssh
!
ntp clock-period 36029198
ntp server 172.16.112.6 key 0 prefer
ntp server 169.229.70.95 key 0 prefer
end
接下来是 2960 交换机 (HDServerSwitch)：
Current configuration : 7496 bytes
!
! Last configuration change at 15:32:04 UTC Mon Apr 7 2014 by admin
! NVRAM config last updated at 15:35:13 UTC Tue Mar 3 2015
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
service sequence-numbers
!
hostname HDServerSwitch
!
boot-start-marker
boot-end-marker
!
aaa new-model
!
aaa session-id common
clock timezone UTC -5 0
!
ip domain-name caymanport.com
ip name-server 172.16.112.6
ip name-server 172.16.112.23
ip name-server 172.16.112.9
udld aggressive
!
mls qos srr-queue output cos-map queue 1 threshold 3 5
mls qos srr-queue output cos-map queue 2 threshold 3 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 2 4
mls qos srr-queue output cos-map queue 4 threshold 2 1
mls qos srr-queue output cos-map queue 4 threshold 3 0
mls qos
!
crypto pki trustpoint TP-self-signed-1538847872
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1538847872
revocation-check none
rsakeypair TP-self-signed-1538847872
!
spanning-tree mode rapid-pvst
spanning-tree loopguard default
spanning-tree extend system-id
!
errdisable recovery cause link-flap
errdisable recovery interval 60
!
vlan internal allocation policy ascending
!
ip ssh time-out 60
ip ssh authentication-retries 2
!
macro global description cisco-global
!
interface Port-channel1
description RumPoint LACP Team
spanning-tree portfast
!
interface FastEthernet0
no ip address
!
interface GigabitEthernet0/1
description VsxHD01-4
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/2
description VsxHD02-6
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/3
description VsxHD01-5
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/4
description VsxHD02-0
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/5
description VsxHD01-3
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/6
description VsxHD02-5
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/7
description VsxHD01-2
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/8
description VsxHD02-4
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/9
description RumPoint-1
spanning-tree portfast
channel-protocol lacp
!
interface GigabitEthernet0/10
description VsxHD02-3 (VL10)
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/11
description RumPoint-2
spanning-tree portfast
!
interface GigabitEthernet0/12
description VsxHD02-7 (VL10)
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/13
spanning-tree portfast
!
interface GigabitEthernet0/14
description VsxHD02-1
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/15
spanning-tree portfast
!
interface GigabitEthernet0/16
description VsxHD02-2
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/17
spanning-tree portfast
!
interface GigabitEthernet0/18
description VsxHD02ILO
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/19
spanning-tree portfast
!
interface GigabitEthernet0/20
spanning-tree portfast
!
interface GigabitEthernet0/21
spanning-tree portfast
!
interface GigabitEthernet0/22
spanning-tree portfast
!
interface GigabitEthernet0/23
spanning-tree portfast
!
interface GigabitEthernet0/24
description KVMHD
spanning-tree portfast
!
interface GigabitEthernet0/25
description CDCVoipSwitch SM-F
switchport mode trunk
mls qos trust cos
macro description cisco-switch
spanning-tree link-type point-to-point
spanning-tree guard none
!
interface GigabitEthernet0/26
description HDSwitch CAT5
switchport mode trunk
shutdown
mls qos trust cos
macro description cisco-switch
spanning-tree link-type point-to-point
!
interface Vlan1
ip address 172.16.112.57 255.255.240.0
!
interface Vlan10
ip address 172.16.200.57 255.255.255.0
!
ip default-gateway 172.16.112.1
ip http server
ip http secure-server
!
logging esm config
logging history size 500
logging history informational
!
line con 0
line vty 0 4
transport input ssh
line vty 5 15
transport input ssh
!
ntp server 172.16.112.6 prefer
ntp server 169.229.70.95 prefer
end
您可以在此处看到网络的拓扑结构：https://i.stack.imgur.com/FJ127.jpg
Netgear 交换机目前连接到 CDCSwitch 端口 30（尽管它曾经连接到 BillingSwitch）。以下是该端口的配置：
interface FastEthernet0/30
description CDCParts1Switch
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree link-type point-to-point
!
CDCVOIPSwitch 和 HDServerSwitch 之间的链接出现故障。
答案1
我不是 STP 专家，但我会尝试一下。
根据 STP 拓扑变化期间发生的情况，短暂的连接丢失对我来说听起来像是预期的行为。
当 STP 拓扑发生变化时（由于交换机端口转换到或从阻塞或转发状态转换，因为交换机或上行链路被添加、移除或发生故障），某些帧可能会因目标 MAC 地址通过不再存在的路径可用而被“黑洞化”。这种情况会一直持续到 STP 收敛并且 MAC 地址表过期，在 STP 拓扑发生变化的情况下，该时间会从默认的 300 秒缩短到 15 秒。由于 MAC 地址表过期，帧也会通过交换基础设施泛滥。
所以再说一次，您所经历的听起来像是预期的行为。