Ethernet Switches & Routers

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Occasional Contributor
Posts: 10
Registered: ‎08-25-2015

Frequent Topology changes

Hi ,

 

We have a Brocade ICX 6430 switch which has been configured  fro MSTP and is root bridge for instance 0 and 2. This is connected to my Netgear switch which is a root bridge for instance  1 and 3.

 

As soon as I connect my brocade switch to the rest of the network the topology changes every 2 mins or so. There are no flapping ports. What can cause frequent topology changes like this in brocade. Can any one suggest any options to troubleshoot this problem.

 

Regards,

Neville

Occasional Contributor
Posts: 7
Registered: ‎01-07-2010

Re: Frequent Topology changes

Does the Netgear run MSTP?

Occasional Contributor
Posts: 10
Registered: ‎08-25-2015

Re: Frequent Topology changes

Yes Netgear has MSTP configured. Brocade switch connects to 2 other cisco switches . I would like to know what is triggering the frequent topology changes. All the switches are configured with MSTP and share the same digest.

 

I have one port which connects to Esxi host, which i find fishy

 

Brocade01#show mstp detail

Port 1/1/13 - Role: DESIGNATED - State: FORWARDING
PathCost 20000, Priority 128, OperEdge T, OperPt2PtMac F, rcvdInternal F, Boundary N/A
Designated - Root 1000cc4e247ae600, RegionalRoot 1000cc4e247ae600,
Bridge 1000cc4e247ae600, ExtCost 0, IntCost 0
ActiveTimers - helloWhen 2
MachineState - PRX-DISCARD, PTX-IDLE, PPM-SENDING_RSTP, PIM-CURRENT
PRT-ACTIVE_PORT, PST-FORWARDING, TCM-INACTIVE
BPDUs - Rcvd MST 0, RST 0, Config 0, TCN 0
Sent MST 18879, RST 0, Config 0, TCN 0

 

Is this correct behaviour? Should I use stp-protect or bpdu-guard comands on this port? Also Cisco has a command like below which gives details to investigate from where the last toplogy change was was received. Is there a command like that in Brocade.

 

Cisco01# show spanning-tree vlan 1 detail

MST0 is executing the mstp compatible Spanning Tree protocol 
Bridge Identifier has priority 61440, sysid 0, address 0025.b4ad.e600 
Configured hello time 2, max age 20, forward delay 15, transmit hold-count 6
Current root has priority 61440, address 0025.b4ad.e480
Root port is 18 (GigabitEthernet0/18), cost of root path is 0
Topology change flag not set, detected flag not set
NUMBER OF TOPOLOGY CHANGES 260 LAST CHANGE OCCURRED 17:30:55 AGO
FROM GIGABITETHERNET0/16
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0

 

 

 

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