Issue in Cisco 2960X switches while configuring redundancy for edge ports.

[mirmohdwasifazam]

 Hi,

      Subject:- issue in Cisco 2960X switches while configuring edge ports.

    we are configuring Cisco 2960X switches  for one of our client company's  project  we have been facing an issue with Cisco 2960X series switches while configuring redundancy for edge devices.

 please find the (attached topology) I'm using 4 nos of Cisco 2960X switches 

with the following part no.WS-C2960X-24PS-L

1.switch 1 (serial no. FCW2037A4WB)

2.switch 2 (serial no. FCW2037A4UU)

3.switch 3 (serial no. FOC2037S03T)

4.switch 4 (serial no. FCW2037A4XE)

1. You can see in the topology diagram that sw1 (switch 1)  and  sw2 (switch 2) is connected to server.

2. (switch 3) sw3 and (switch 4) sw4 are connected to client PC and PLC device. 

3.I have enable teaming in server and client PC 

4.I have 2 nos of  Ethernet ports on PLC device each cable connected to sw3 and sw4 like a bridge configuration.

when I perform a  ping test  from server to remote end devices i.e client PC as well as PLC device  and switch off sw1  the time delay is  just only 1 millisecond communication is stopped and same test I did  for sw2 as well the result is same.

     But  when we perform ping test from server to  client PC and  PLC  than  switch off sw3 I observe that for client PC  just a single packet is lost but PLC communication is stopped for more than 32 seconds.

the client PC is working fine because time delay is just only 1 millisecond

But the problem is in plc device when sw3 is off the request timeout delay is more than 30 seconds

I have already  configured spanning-tree mode rapid-pvst  and spanning-tree portfast commands is all switches (please find the attached backup of switches).

All the ports are moved to vlan 2.The default priority is changed for vlan 2 with the following priority mentioned below.

sw1. priority 4096 

sw2. priority 8192

sw3. priority 12288

sw4. priority 16384

so the block port is in  between sw3& sw4  (Gi0/23&24) ports. 

could you please let  me know what action is to be taken to avoid time delay of 32 seconds for PLC to  reduced to just 1 second in case of switch 3 or switch 4 fail-over.

-------------------sw1 backup----------------------------------------------------

!
! Last configuration change at 14:54:20 UTC Sat Jan 28 2017
! NVRAM config last updated at 14:56:10 UTC Sat Jan 28 2017
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TWK-SW1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$k8s6$kE7K7K.zMWIS2GpqJfJ2I0
!
username dno password 0 dno
no aaa new-model
clock timezone UTC 3 0
switch 1 provision ws-c2960x-24ps-l
!
!
no ip domain-lookup
!
!
!
!
!
!
!
crypto pki trustpoint TP-self-signed-1513073280
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1513073280
revocation-check none
rsakeypair TP-self-signed-1513073280
!
!
crypto pki certificate chain TP-self-signed-1513073280
certificate self-signed 01 nvram:IOS-Self-Sig#1.cer
!
spanning-tree mode rapid-pvst
spanning-tree portfast default
spanning-tree extend system-id
spanning-tree vlan 2 priority 4096
!
!
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
switchport mode trunk
!
interface FastEthernet0
ip address 192.168.2.1 255.255.255.0
!
interface GigabitEthernet1/0/1
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/2
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/3
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/4
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/5
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/6
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/7
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/8
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/9
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/10
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/11
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/12
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/13
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/14
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/15
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/16
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/17
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/18
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/19
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/20
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/21
switchport mode trunk
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/24
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/25
switchport mode trunk
!
interface GigabitEthernet1/0/26
switchport mode trunk
!
interface GigabitEthernet1/0/27
switchport mode trunk
!
interface GigabitEthernet1/0/28
switchport mode trunk
!
interface Vlan1
no ip address
!
interface Vlan2
ip address 192.168.1.251 255.255.255.0
!
ip http server
ip http secure-server
!
!
logging trap debugging
logging host 192.168.1.5
!
!
!
line con 0
line vty 0 4
privilege level 15
password dno
no login
line vty 5 15
password dno
login
!
end

------------------------------sw2 backup -----------------------------------------

!
! Last configuration change at 14:53:02 UTC Sat Jan 28 2017
! NVRAM config last updated at 14:55:20 UTC Sat Jan 28 2017
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TWK_SW2
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$eEhR$Ne1qXlp.Qk9tkFHlZ3Cmu.
!
username dno password 0 dno
no aaa new-model
clock timezone UTC 3 0
switch 1 provision ws-c2960x-24ps-l
!
!
no ip domain-lookup
!
!
!
!
!
!
!
crypto pki trustpoint TP-self-signed-1519136512
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1519136512
revocation-check none
rsakeypair TP-self-signed-1519136512
!
!
crypto pki certificate chain TP-self-signed-1519136512
certificate self-signed 01 nvram:IOS-Self-Sig#1.cer
!
spanning-tree mode rapid-pvst
spanning-tree portfast default
spanning-tree extend system-id
spanning-tree vlan 2 priority 8192
!
!
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
switchport mode trunk
!
interface FastEthernet0
ip address 192.168.2.2 255.255.255.0
!
interface GigabitEthernet1/0/1
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/2
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/3
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/4
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/5
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/6
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/7
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/8
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/9
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/10
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/11
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/12
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/13
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/14
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/15
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/16
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/17
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/18
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/19
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/20
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/21
switchport mode trunk
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/24
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/25
switchport mode trunk
!
interface GigabitEthernet1/0/26
switchport mode trunk
!
interface GigabitEthernet1/0/27
switchport mode trunk
!
interface GigabitEthernet1/0/28
switchport mode trunk
!
interface Vlan1
no ip address
!
interface Vlan2
ip address 192.168.1.252 255.255.255.0
!
ip http server
ip http secure-server
!
!
logging trap debugging
logging host 192.168.1.5
!
!
!
line con 0
line vty 0 4
privilege level 15
password dno
no login
line vty 5 15
password dno
login
!
end

------------------------------sw3 backup----------------------------------------

!
! Last configuration change at 15:23:34 UTC Sat Jan 28 2017
! NVRAM config last updated at 16:51:44 UTC Sat Jan 28 2017
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TWK_SW3
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$DlC/$Di0eOzDd0Guf3Z.6PJI/g1
!
username dno password 0 dno
no aaa new-model
clock timezone UTC 3 0
switch 1 provision ws-c2960x-24ps-l
!
!
no ip domain-lookup
!
!
!
!
!
!
!
crypto pki trustpoint TP-self-signed-1510133632
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1510133632
revocation-check none
rsakeypair TP-self-signed-1510133632
!
!
crypto pki certificate chain TP-self-signed-1510133632
certificate self-signed 01 nvram:IOS-Self-Sig#1.cer
!
spanning-tree mode rapid-pvst
spanning-tree portfast default
spanning-tree extend system-id
spanning-tree vlan 2 priority 12288
!
!
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
switchport mode trunk
!
interface FastEthernet0
ip address 192.168.2.3 255.255.255.0
!
interface GigabitEthernet1/0/1
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/2
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/3
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/4
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/5
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/6
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/7
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/8
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/9
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/10
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/11
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/12
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/13
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/14
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/15
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/16
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/17
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/18
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/19
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/20
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/21
switchport mode trunk
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/24
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/25
switchport mode trunk
!
interface GigabitEthernet1/0/26
switchport mode trunk
!
interface GigabitEthernet1/0/27
switchport mode trunk
!
interface GigabitEthernet1/0/28
switchport mode trunk
!
interface Vlan1
no ip address
!
interface Vlan2
ip address 192.168.1.253 255.255.255.0
!
ip http server
ip http secure-server
!
!
logging trap debugging
logging host 192.168.1.5
!
!
!
line con 0
line vty 0 4
privilege level 15
password dno
no login
line vty 5 15
password dno
login
!
end

----------------------------------------sw4 backup-----------------------------------------------

!
! Last configuration change at 16:53:35 UTC Sat Jan 28 2017
! NVRAM config last updated at 16:53:37 UTC Sat Jan 28 2017
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TWK_SW4
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$N1wC$SkkCnLVBJ.v1XKr9isUGJ/
!
username dno password 0 dno
no aaa new-model
clock timezone UTC 3 0
switch 1 provision ws-c2960x-24ps-l
!
!
no ip domain-lookup
!
!
!
!
!
!
!
crypto pki trustpoint TP-self-signed-1515756288
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1515756288
revocation-check none
rsakeypair TP-self-signed-1515756288
!
!
crypto pki certificate chain TP-self-signed-1515756288
certificate self-signed 01 nvram:IOS-Self-Sig#1.cer
!
spanning-tree mode rapid-pvst
spanning-tree portfast default
spanning-tree extend system-id
spanning-tree vlan 2 priority 16384
!
!
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
switchport mode trunk
!
interface FastEthernet0
ip address 192.168.2.4 255.255.255.0
!
interface GigabitEthernet1/0/1
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/2
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/3
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/4
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/5
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/6
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/7
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/8
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/9
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/10
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/11
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/12
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/13
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/14
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/15
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/16
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/17
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/18
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/19
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/20
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/21
switchport mode trunk
!
interface GigabitEthernet1/0/22
!
interface GigabitEthernet1/0/23
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/24
switchport mode trunk
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/25
switchport mode trunk
!
interface GigabitEthernet1/0/26
switchport mode trunk
!
interface GigabitEthernet1/0/27
switchport mode trunk
!
interface GigabitEthernet1/0/28
switchport mode trunk
!
interface Vlan1
no ip address
!
interface Vlan2
ip address 192.168.1.254 255.255.255.0
!
ip http server
ip http secure-server
!
!
logging trap debugging
logging host 192.168.1.5
!
!
!
line con 0
line vty 0 4
privilege level 15
password dno
no login
line vty 5 15
password dno
login
!
end

Thanks & Regards

wasif 

[Collin Clark]

This is a PLC issue, not a configuration issue. The server fails over quicker b/c the NIC's are teamed. The PLC can't do NIC teaming so it must go through the spanning tree stages when a link goes up/down.