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New Member

mst traffic problem

Hi all.

I configured two mst regions in a conf where  2 Catalyst 6500 are the main bridge for instance 1 & 2. Lets say catalyst 1 is the bridge for mst1 & catalyst 2 is the bridge for mst2. these two switch are connected via an Etherchannel composed by two gigabit ethernel. The other switches are conected via fastEthernet interfaces once to catalyst1 and once to catalyst2.

The problem is that when whe send traffic (let's say we copy 5Gbytes of data). from one vlan belonging to   an mst region all the switch show the same traffic in the concerned interface. Let's say the machine origen of the copy is in a vlan belonging to mst instance2 , all the switch will have traffic in the interface connected to catalyst 2.

Any ideas please??


New Member

Re: mst traffic problem


I am still trying to understand your question.

catalyst switch 1 ------------------------- catalyst switch 2

          |                                                  |

          |                                                  |

ACCESS SWITCH 1                    ACCESS SWITCH 2

          |                                                  |

          |                                                  |

          |                                                  |

     HOST A                                      HOST B

So, you are trying to send traffic from Host A to Host B. Which interfaces are you checking the packets? How are you checking that ?



New Member

Re: mst traffic problem


you can find in this attachement the network schema. As you can see there are several switches carriyng vlan traffic.

When setting MST we notice that when we do copy of data from one host to another, lets say host A & B belongs to the same vlan (wich belongs to instance 2), but host A is  in switch 1 and hostB in switch B. When the copy is executed we see the same amount of inbound traffic in the  interface connected to catalyst2   in all switches at the same time.

Thank you very much

New Member

Re: mst traffic problem


In order to solve this problem we have decided check up the  config of all  switches and  to put all access link in portfast and bpdufilter.

Apparently there is a global command that put all the portfast port in bdpufilter at the same time

"spanning-tree bpdufilter enable"

is it save to in a production switch?