I have a switch that is not receiving BPDU Hellos properly and I have not been able to pin point the problem. Switch 1 puts all ports for vlan4 into desg mode and claims it is the root for vlan4 (the root is upstream), while switch 2 knows the root is upstream on port Gi0/24, so it places that port as root and Gi017 as desg. Running debug spanning-tree events shows that each side sends BPDU's to the other but they do not arrive. So i have no idea why switch 1 will not realize it is not root for vlan4. The only way I can get this switch to not think it is root is to put the interface on both ends of the trunk as access and set the access vlan to 4.
Switch1 Interface 0/24 is configured as follows:
interface GigabitEthernet0/24
switchport trunk allowed vlan 1,4
switchport mode trunk
Swtich2 Interface G0/17 is configured as follows:
interface GigabitEthernet0/17
switchport trunk allowed vlan 1,4
switchport mode trunk
Show Spanning-tree results Switch1
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 16385
Address 4055.39cc.6780
Cost 12
Port 24 (GigabitEthernet0/24)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0021.1b59.ae80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
Gi0/24 Root FWD 4 128.24 P2p Peer(STP)
VLAN0004
Spanning tree enabled protocol rstp
Root ID Priority 61444
Address 0021.1b59.ae80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 61444 (priority 61440 sys-id-ext 4)
Address 0021.1b59.ae80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
Gi0/18 Desg FWD 4 128.18 P2p
Gi0/24 Desg FWD 4 128.24 P2p
Switch2
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 16385
Address 4055.39cc.6780
Cost 4
Port 24 (GigabitEthernet0/24)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0021.1b59.cb00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
Gi0/10 Desg FWD 4 128.10 Edge P2p
Gi0/11 Desg FWD 4 128.11 Edge P2p
Gi0/12 Desg FWD 4 128.12 Edge P2p
Gi0/13 Desg FWD 4 128.13 Edge P2p
Gi0/14 Desg FWD 19 128.14 Edge P2p
Gi0/15 Desg FWD 19 128.15 Edge P2p
Gi0/16 Desg FWD 19 128.16 Edge P2p
Gi0/17 Desg FWD 4 128.17 P2p Peer(STP)
Gi0/18 Desg FWD 4 128.18 Edge P2p
Gi0/19 Desg FWD 19 128.19 Edge P2p
Gi0/20 Desg FWD 19 128.20 Edge P2p
Gi0/24 Root FWD 4 128.24 P2p
VLAN0004
Spanning tree enabled protocol rstp
Root ID Priority 16388
Address 4055.39cc.6780
Cost 4
Port 24 (GigabitEthernet0/24)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32772 (priority 32768 sys-id-ext 4)
Address 0021.1b59.cb00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
Gi0/17 Desg FWD 4 128.17 P2p
Gi0/24 Root FWD 4 128.24 P2p
Other Information about the trunk...
Switch 1
Show Interface Trunk
Port Mode Encapsulation Status Native vlan
Gi0/24 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/24 1,4
Port Vlans allowed and active in management domain
Gi0/24 1,4
Port Vlans in spanning tree forwarding state and not pruned
Gi0/24 1,4
Switch2
Port Mode Encapsulation Status Native vlan
Gi0/17 on 802.1q trunking 1
Gi0/24 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/17 1,4
Gi0/24 1-4094
Port Vlans allowed and active in management domain
Gi0/17 1,4
Gi0/24 1-4,10,100-101,600
Port Vlans in spanning tree forwarding state and not pruned
Gi0/17 1,4
Gi0/24 1-4,100-101
Show CDP NE Switch1
Switch1#sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay
Device ID Local Intrfce Holdtme Capability Platform Port ID
Switch2 Gig 0/24 140 S I WS-C2960G Gig 0/17
Switch2
switch2#sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID Local Intrfce Holdtme Capability Platform Port ID
Switch.domain.lcl
Gig 0/17 159 S I WS-C2960G Gig 0/24
root-3750 Gig 0/24 164 R S I WS-C3750X Gig 2/0/20
Switch1 Configuration file
Current configuration : 2834 bytes
!
! Last configuration change at 15:14:14 EST Thu Oct 6 2016
! NVRAM config last updated at 10:45:43 EST Thu Oct 6 2016
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Switch1
!
boot-start-marker
boot-end-marker
!
!
!
!
no aaa new-model
clock timezone EST -5
system mtu routing 1500
udld enable
!
!
ip domain-lookup source-interface GigabitEthernet0/24
ip domain-name .......
!
!
!
!
!
!
spanning-tree mode pvst
spanning-tree logging
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
ip tftp source-interface Vlan1
!
!
interface GigabitEthernet0/1
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/2
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/3
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/4
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/5
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/6
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/7
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/8
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/9
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/10
switchport access vlan 4
!
interface GigabitEthernet0/11
switchport access vlan 4
!
interface GigabitEthernet0/12
switchport access vlan 4
!
interface GigabitEthernet0/13
switchport access vlan 4
!
interface GigabitEthernet0/14
switchport access vlan 4
!
interface GigabitEthernet0/15
switchport access vlan 4
!
interface GigabitEthernet0/16
switchport access vlan 4
!
interface GigabitEthernet0/17
switchport access vlan 4
!
interface GigabitEthernet0/18
switchport access vlan 4
!
interface GigabitEthernet0/19
switchport access vlan 4
!
interface GigabitEthernet0/20
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/21
switchport access vlan 4
!
interface GigabitEthernet0/22
switchport access vlan 4
!
interface GigabitEthernet0/23
switchport access vlan 4
switchport mode access
!
interface GigabitEthernet0/24
description Trunk to switch2
switchport trunk allowed vlan 1,4
switchport mode trunk
!
interface Vlan1
ip address dhcp
!
interface Vlan4
ip address xxx.xxx.xxx.x xxx.xxx.xxx.x
!
ip default-gateway xxx.xxx.x.x
ip http server
ip http secure-server
!
line con 0
exec-timeout 40 0
logging synchronous
line vty 0 4
login
line vty 5 15
login
!
!
monitor session 61 source vlan 4
ntp clock-period ..........
ntp server ........
end
Switch2 Configuration file
Current configuration : 5278 bytes
!
! Last configuration change at 16:12:50 EDT Thu Oct 6 2016 by
! NVRAM config last updated at 15:37:44 EDT Thu Oct 6 2016 by
!
version 12.2
no service pad
service timestamps debug datetime
service timestamps log datetime
service password-encryption
!
hostname Switch2
!
enable secret ..
!
username ..
username ..
aaa new-model
aaa authentication login .. group radius local
aaa authentication login .. group radius local
aaa authentication enable default group radius enable
aaa authorization console
aaa authorization exec ... group radius local
aaa authorization exec ... group radius local
!
aaa session-id common
clock timezone EST -5
clock summer-time EDT recurring
system mtu routing 1500
udld enable
ip subnet-zero
!
no ip domain-lookup
!
!
!
no file verify auto
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
interface GigabitEthernet0/1
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/2
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/3
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/4
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/5
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/6
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/7
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/8
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/9
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/10
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/11
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/12
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/13
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/14
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/15
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/16
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/17
description Trunk to Switch1
switchport trunk allowed vlan 1,4
switchport mode trunk
!
interface GigabitEthernet0/18
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/19
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/20
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/21
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/22
switchport access vlan 3
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/23
switchport mode trunk
spanning-tree portfast
!
interface GigabitEthernet0/24
switchport mode trunk
spanning-tree portfast
!
interface Vlan1
ip address xxx.xxx.xxx.xxx xxx.xxx.xxx.x
no ip route-cache
!
interface Vlan4
no ip address
no ip route-cache
!
interface Vlan11
ip address xxx.xxx.xxx.xxx xxx.xxx.xxx.x
no ip route-cache
!
interface Vlan66
no ip address
no ip route-cache
shutdown
!
ip default-gateway xx.x.x.x
no ip http server
ip radius source-interface Vlan1
snmp-server community xxxxxxxxx XX
radius-server host xxx.xxx.xx.x auth-port .......
radius-server source-ports ..........
!
control-plane
!
!
line con 0
exec-timeout 5 0
password .......
authorization exec ....
logging synchronous
login authentication .....
line vty 0 4
exec-timeout 14 59
password 7 ......
authorization exec ......
logging synchronous
login authentication ....
length 0
history size 40
line vty 5 15
exec-timeout 14 59
password .......
authorization exec.....
logging synchronous
login authentication.....
length 0
history size 40
!
!
ntp clock-period ......
ntp server ......
end
Root-2750 Switch This Bridge is root for ALL vlans.
!
version 12.2
no service pad
service timestamps debug datetime localtime
service timestamps log datetime localtime
service password-encryption
service sequence-numbers
!
hostname Root-3750
!
boot-start-marker
boot-end-marker
!
enable secret 5
!
!
!
aaa new-model
!
!
aaa authentication login .. group radius local
aaa authentication login.. group radius local
aaa authentication enable default group radius enable
aaa authorization console
aaa authorization exec ..group radius local
aaa authorization exec .. group radius local
!
!
!
aaa session-id common
clock timezone EST -5
clock summer-time EDT recurring
switch 1 provision ws-c3750x-24
switch 2 provision ws-c3750x-24
system mtu routing 1500
ip routing
ip dhcp excluded-address ...
ip dhcp excluded-address ...
!
ip dhcp pool Phones
network ....
default-router ....
domain-name ...
dns-server ...
option 160 ascii .......
!
!
ip name-server ....
ip name-server ...
!
track 1 ip sla 1 reachability
!
track 2 ip sla 2 reachability
!
track 10 list boolean or
object 1
object 2
!
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 .............
enrollment selfsigned
..............
.............
...............
!
!
crypto pki certificate chain,,,,,,,,,,,,,
certificate s,,,,,,,,,,,
,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
quit
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
spanning-tree vlan 1-4094 priority 16384
!
!
!
!
vlan internal allocation policy ascending
!
ip ssh time-out,,,,
ip ssh ve,,,,,,
lldp run
!
!
!
interface Port-channel1
!
interface Port-channel2
!
interface Port-channel3
!
interface Port-channel4
!
interface Port-channel5
!
interface FastEthernet0
no ip address
no ip route-cache cef
no ip route-cache
no ip mroute-cache
shutdown
!
interface GigabitEthernet1/0/1
description ..
spanning-tree portfast
!
interface GigabitEthernet1/0/2
description ..
spanning-tree portfast
!
interface GigabitEthernet1/0/3
description...
spanning-tree portfast
!
interface GigabitEthernet1/0/4
description
spanning-tree portfast
!
interface GigabitEthernet1/0/5
description
spanning-tree portfast
!
interface GigabitEthernet1/0/6
description
spanning-tree portfast
!
interface GigabitEthernet1/0/7
description
spanning-tree portfast
!
interface GigabitEthernet1/0/8
description
spanning-tree portfast
!
interface GigabitEthernet1/0/9
description
spanning-tree portfast
!
interface GigabitEthernet1/0/10
description
spanning-tree portfast
!
interface GigabitEthernet1/0/11
description
spanning-tree portfast
!
interface GigabitEthernet1/0/12
description
spanning-tree portfast
!
interface GigabitEthernet1/0/13
description
spanning-tree portfast
!
interface GigabitEthernet1/0/14
description
spanning-tree portfast
!
interface GigabitEthernet1/0/15
description
spanning-tree portfast
!
interface GigabitEthernet1/0/16
description
spanning-tree portfast
!
interface GigabitEthernet1/0/17
description to
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/18
description
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/19
description
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/20
description
switchport access vlan 2
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/21
description OPEN
switchport trunk encapsulation dot1q
switchport mode access
!
interface GigabitEthernet1/0/22
description OPEN
switchport trunk encapsulation dot1q
switchport mode trunk
shutdown
!
interface GigabitEthernet1/1/1
description Trunk 2 a switch
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-599,601-4094
switchport mode trunk
!
interface GigabitEthernet1/1/2
description Trunk to a switch
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-599,601-4094
switchport mode trunk
!
interface GigabitEthernet1/1/3
description Trunk to a switch
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-599,601-4094
switchport mode trunk
!
interface GigabitEthernet1/1/4
description
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet2/0/20
description Switch2
switchport trunk allowed vlan 1-599,601-4094
spanning-tree portfast
!
interface GigabitEthernet2/0/24
description
switchport access vlan 600
switchport mode access
load-interval 30
!
!
interface Vlan1
ip address ..
!
interface Vlan2
description
ip address ..
!
interface Vlan3
ip address ...
!
interface Vlan4
ip address ..
ip helper-address ...
!
interface Vlan100
ip address ..
!
interface Vlan101
ip address ..
!
interface Vlan600
ip address ....
ip summary-address eigrp ..
!
!
router eigrp 100
network .
network..
network .....
network .
network ..
!
ip classless
ip route
ip route.
ip route ..
ip route ..
ip route .....
ip route ..
ip route ..
ip route ..
ip route ..
ip route ..
ip route ..
ip route...
ip route ...
!
ip http server
ip http secure-server
!
ip access-list standard ..
permit ..
permit ..
permit ...
permit ...
!
ip access-list extended .....
permit ip host ..... any
ip access-list extended ..
permit ip host ...any
permit ip host .. any
permit ip host .......any
permit ip host ....... any
permit ip host ..... any
permit ip host ...... any
permit ip host ........ any
permit ip host .... any
permit ip host ...... any
permit ip host ...... any
permit ip host ...... any
permit ip host ........ any
permit ip host ........ any
permit ip host .. any
permit ip host .. any
!
ip radius source-interface Vlan1
ip sla 1
dns w...
frequency 10
ip sla schedule 1 life forever start-time now
ip sla 2
icmp-echo 4.2.2.1
frequency 10
ip sla schedule 2 life forever start-time now
ip sla enable reaction-alerts
route-map TEST permit 5
match ip address TEST
set ip next-hop ..
!
route-map .. permit 5
match ip address ..
set ip next-hop ...
!
route-map ...permit 10
match ip address ..
!
snmp-server community read4netmon RO
radius-server host ... auth-port . acct-port ...key..
!
!
line con 0
exec-timeout 5 0
password ..
authorization exec ..
logging synchronous
login authentication ..
line vty 0 4
session-timeout 4 output
exec-timeout 4 59
password ..
authorization exec ..
logging synchronous
login authentication..
transport input ssh
line vty 5 15
session-timeout 4 output
exec-timeout 4 59
password ...
authorization exec ..
logging synchronous
login authentication ..
length 0
transport input ssh
!
ntp clock-period 36027768
ntp server ..........
end
Root-3750 Trunk ports & Show cdp ne
Root-3750#sh int trunk
Port Mode Encapsulation Status Native vlan
Gi1/1/1 on 802.1q trunking 1
Gi1/1/2 on 802.1q trunking 1
Gi1/1/3 on 802.1q trunking 1
Gi2/0/20 auto n-802.1q trunking 1
Port Vlans allowed on trunk
Gi1/1/1 1-599,601-4094
Gi1/1/2 1-599,601-4094
Gi1/1/3 1-599,601-4094
Gi2/0/20 1-599,601-4094
Port Vlans allowed and active in management domain
Gi1/1/1 1-4,10,100-101
Gi1/1/2 1-4,10,100-101
Gi1/1/3 1-4,10,100-101
Gi2/0/20 1-4,10,100-101
Port Vlans in spanning tree forwarding state and not pruned
Gi1/1/1 1,4,100
Gi1/1/2 1,4,100
Gi1/1/3 1,100
Gi2/0/20 1,3-4
show cdp neighbor
from each switch). Also, having the full switch configurations, including the switch which is supposed to be the root switch.Vlan 4
. For trunks which you set toswitchport mode trunk
, you should also setswitchport mode nonegotiate
to disable DTP. You can setportfast
andbpduguard
globally, so that you don't have to set it on every access port. You didn't include the root switch configuration, so I can't see if you properly set the VLAN priority. At the very least, try defining the VLANs at layer-2. Not doing that sometimes causes weird problems.