我有一个非常奇怪的问题，我希望有人能给我一个关于在哪里看的想法。我有一个新的 Netgear M4100-D10-POE 第 2 层托管交换机，我们正在远程建筑物中安装它。它通过 CAT5 电缆连接到外部网络的其余部分到 Cisco 交换机（我们有几个，它连接的位置似乎并不重要）。现在它工作正常，但当我关闭这个 Netgear 交换机（或从网络上拔下它）时，我收到一堆来自各种服务的电子邮件，表明一对其他 Cisco 交换机（Catalyst 3560 和催化剂 2960S)。这些交换机通过光纤线相互连接。
奇怪的是，Netgear 交换机没有直接连接到遭受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 个其他 Cisco 交换机。我也没有在任一交换机上看到任何排序端口向上/向下日志消息。我也知道这不是巧合，因为我可以随时通过插拔 Netgear 交换机来重现问题。
我唯一的猜测是它与 BGP、STP 或其他一些交换机到交换机协议有关，但我不知道如何监控它。
更新：这是配置文件。首先是网件交换机：
!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
现在的 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
您可以在此处查看网络的拓扑：http: //imgur.com/1CvaqUt
The Netgear switch is connected to CDCSwitch port 30 right now (although it was connected to BillingSwitch at one point). Here is the config for that port:
interface FastEthernet0/30
description CDCParts1Switch
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree link-type point-to-point
!
It is the link between CDCVOIPSwitch and HDServerSwitch that's going down.
I'm not an STP expert, but I'll take a crack at this.
The brief loss of connectivity sounds like the expected behavior to me, based on what happens during an STP topology change.
When the STP topology changes (due to a switch port transitioning to or from the blocking or forwarding state, because a switch or uplink is added, removed or fails), some frames may be "blackholed" due to the destination MAC address being available via a path that no longer exists. This occurs until STP converges and the MAC address table expires, which in the case of an STP topology change is reduced from the default of 300 seconds to 15 seconds. Frames will also be flooded through the switching infrastructure as a result of the MAC address tables expiring.
So again, what you're experiencing sounds like the expected behavior.