router lan connection to switch

[GM2005]

Hi

I have a Cisco 877. When my customer connects the LAN port to their 3650 PoE switch, it shuts down every port. The router was fine until the new switch was added, it was previously connected to an HP switch.

Has anyone any idea of what could be causing this? I can post the relevant parts of the config if required.

 

[ADB100]

It sounds like some of the advanced STP features have been enabled (BPDU-Guard or Loop-Guard). You should probably post the configs (or parts of) of the 877 and the 3560.

Andy

 

[Minue]

Hello
I would start at layer 1.Is the cable a crossover?Is it a good cable?If any of the isn't the problem.The only logical issue could be spanning-tree.These 3560 are very intelligent swicthes,could be some default protection system that's triggered.Would be a good idea to post the conf.
Regards

 

[GM2005]

I have chopped out the irrelevant bits. There are some stp and other mechanisms configured.

service timestamps debug uptime
service timestamps log datetime
no service password-encryption
service sequence-numbers
!
hostname xxxxxxxxx
!
no logging console

!

no aaa new-model
clock timezone GMT 0
clock summer-time GMT recurring last Sun Mar 1:00 last Sun Oct 2:00
system mtu routing 1500
udld aggressive

ip subnet-zero
!
!

!
macro global description cisco-global
errdisable recovery cause link-flap
errdisable recovery interval 60
no file verify auto
!
spanning-tree mode rapid-pvst
spanning-tree loopguard default
spanning-tree extend system-id
!
vlan internal allocation policy ascending
interface GigabitEthernet0/40
power inline never
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust cos
macro description cisco-wireless
auto qos voip trust
spanning-tree bpduguard enable
!
interface GigabitEthernet0/41
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
macro description cisco-switch
auto qos voip trust
spanning-tree link-type point-to-point
!
interface GigabitEthernet0/42
!
interface GigabitEthernet0/43
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
macro description cisco-switch
auto qos voip trust
spanning-tree link-type point-to-point
!
interface GigabitEthernet0/44
!
interface GigabitEthernet0/45
!
interface GigabitEthernet0/46
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
mls qos trust cos
macro description cisco-wireless
auto qos voip trust
spanning-tree bpduguard enable
!
interface GigabitEthernet0/47
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
macro description cisco-switch
auto qos voip trust
spanning-tree link-type point-to-point
!
interface GigabitEthernet0/48
!
interface GigabitEthernet0/49
!
interface GigabitEthernet0/50
!
interface GigabitEthernet0/51
!
interface GigabitEthernet0/52
!
interface Vlan1

ip classless
ip http server
!
!
control-plane
!
!
line con 0
line vty 0 4
password selection
login
length 0
line vty 5 15
password selection
login
!
end

 

[Minue]

Hello
It must be some spanning-tree issue could be the problem do have any known loops in the network.
For testing purposes try turning off "spanning-tree loopguard default"If the problem persist try plugging the Router into one off the the port that isn't configured,ex."interface GigabitEthernet0/48"
Regards

 

[GM2005]

Thanks. I'll try that. I strongly suspect there is a loop and we are not being told about it.

 

[brianinms]

If you are connecting the 871 to any of the ports configured with spanning-tree bpduguard enable then it is what is downing the connection.

 

[pmoorey]

Try issue:

router#show spanning-tree blocked

This will indicate which ports have been put into blocking mode as loops have been detected.

Additionally, try:

router#show spanning inconsistant

This will identify any ports that are in an inconsistant spanning-tree state.

HTH

Regards,


Peter
CCNA, Cisco Qualified Specialist

 

[GM2005]

Thanks all. I'll let you know when I go there and see it for myself just what is causing the problem. Just to confirm, when the ethernet port of the router is connected to the switch, it sends every port into either blocking or errdisable. I cannot confirm right now which state as the switch log buffers were too small and were overwritten.