Ethernet Switches & Routers

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Posts: 1
Registered: ‎11-14-2011

MLX with MSTP and STP protocol migration

Hello,

I've got an MLX with MSTP configured. It is connected to an (unconfigured) FLX talking default STP. I expected the MSTP device to recognize the STP BPDUs and fall back to STP itself by protocol migration. Doesn't look like it does.

This is what is happening on the wire :

No.     Time        Source                Destination           Protocol Info
      1 0.000000    mlx                   IEEE_STP              STP      MST. Root = 4096/0/00:24:38:95:53:00  Cost = 0  Port = 0x8157

Frame 1: 119 bytes on wire (952 bits), 119 bytes captured (952 bits)
IEEE 802.3 Ethernet 
Logical-Link Control
Spanning Tree Protocol
    Protocol Identifier: Spanning Tree Protocol (0x0000)
    Protocol Version Identifier: Multiple Spanning Tree (3)
    BPDU Type: Rapid/Multiple Spanning Tree (0x02)
    BPDU flags: 0x7e (Agreement, Forwarding, Learning, Port Role: Designated, Proposal)
    Root Identifier: 4096 / 0 / 00:24:38:95:53:00
    Root Path Cost: 0
    Bridge Identifier: 4096 / 0 / 00:24:38:95:53:00
    Port identifier: 0x8157
    Message Age: 0
    Max Age: 20
    Hello Time: 2
    Forward Delay: 15
    Version 1 Length: 0
    Version 3 Length: 64
    MST Extension
        MST Config ID format selector: 0
        MST Config name: molgen
        MST Config revision: 0
        MST Config digest: ac36177f50283cd4b83821d8ab26de62
        CIST Internal Root Path Cost: 0
        CIST Bridge Identifier: 4096 / 0 / 00:24:38:95:53:00
            CIST Bridge Priority: 4096
            CIST Bridge Identifier System ID Extension: 0
            CIST Bridge Identifier System ID: 00:24:38:95:53:00
        CIST Remaining hops: 20

No.     Time        Source                Destination           Protocol Info
      2 0.701592    BrocadeC_52:58:f3     IEEE_STP              STP      Conf. Root = 32768/0/74:8e:f8:52:58:c0  Cost = 0  Port = 0x8081

Frame 2: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
IEEE 802.3 Ethernet 
Logical-Link Control
Spanning Tree Protocol
    Protocol Identifier: Spanning Tree Protocol (0x0000)
    Protocol Version Identifier: Spanning Tree (0)
    BPDU Type: Configuration (0x00)
    BPDU flags: 0x00
    Root Identifier: 32768 / 0 / 74:8e:f8:52:58:c0
    Root Path Cost: 0
    Bridge Identifier: 32768 / 0 / 74:8e:f8:52:58:c0
    Port identifier: 0x8081
    Message Age: 0
    Max Age: 20
    Hello Time: 2
    Forward Delay: 15

No.     Time        Source                Destination           Protocol Info
      3 2.007194    mlx                   IEEE_STP              STP      MST. Root = 4096/0/00:24:38:95:53:00  Cost = 0  Port = 0x8157

Frame 3: 119 bytes on wire (952 bits), 119 bytes captured (952 bits)
IEEE 802.3 Ethernet 
Logical-Link Control
Spanning Tree Protocol
    Protocol Identifier: Spanning Tree Protocol (0x0000)
    Protocol Version Identifier: Multiple Spanning Tree (3)
    BPDU Type: Rapid/Multiple Spanning Tree (0x02)
    BPDU flags: 0x7e (Agreement, Forwarding, Learning, Port Role: Designated, Proposal)
    Root Identifier: 4096 / 0 / 00:24:38:95:53:00
    Root Path Cost: 0
    Bridge Identifier: 4096 / 0 / 00:24:38:95:53:00
    Port identifier: 0x8157
    Message Age: 0
    Max Age: 20
    Hello Time: 2
    Forward Delay: 15
    Version 1 Length: 0
    Version 3 Length: 64
    MST Extension
        MST Config ID format selector: 0
        MST Config name: molgen
        MST Config revision: 0
        MST Config digest: ac36177f50283cd4b83821d8ab26de62
        CIST Internal Root Path Cost: 0
        CIST Bridge Identifier: 4096 / 0 / 00:24:38:95:53:00
            CIST Bridge Priority: 4096
            CIST Bridge Identifier System ID Extension: 0
            CIST Bridge Identifier System ID: 00:24:38:95:53:00
        CIST Remaining hops: 20

No.     Time        Source                Destination           Protocol Info
      4 2.701728    BrocadeC_52:58:f3     IEEE_STP              STP      Conf. Root = 32768/0/74:8e:f8:52:58:c0  Cost = 0  Port = 0x8081

Frame 4: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
IEEE 802.3 Ethernet 
Logical-Link Control
Spanning Tree Protocol
    Protocol Identifier: Spanning Tree Protocol (0x0000)
    Protocol Version Identifier: Spanning Tree (0)
    BPDU Type: Configuration (0x00)
    BPDU flags: 0x00
    Root Identifier: 32768 / 0 / 74:8e:f8:52:58:c0
    Root Path Cost: 0
    Bridge Identifier: 32768 / 0 / 74:8e:f8:52:58:c0
    Port identifier: 0x8081
    Message Age: 0
    Max Age: 20
    Hello Time: 2
    Forward Delay: 15

Here some output from the MLX:

SSH@mlx(config)#show mstp deta | begin 8/7
Port 8/7 - Role: DESIGNATED - State: FORWARDING
  PathCost 2000, Priority 128, OperEdge F, OperPt2PtMac T, Boundary F
  Designated   - Root 1000002438955300, RegionalRoot 1000002438955300,
                 Bridge 1000002438955300, ExtCost 0, IntCost 0
  ActiveTimers - helloWhen 1 recover timer 0
  MachineState - PRX-DISCARD, PTX-IDLE, PPM-SENDING_RSTP, PIM-CURRENT
                 PRT-ACTIVE_PORT, PST-FORWARDING, TCM-ACTIVE
  BPDUs        - Rcvd MST 38, RST 0, Config 0, TCN 0
                 Sent MST 34542, RST 0, Config 0, TCN 0

SSH@mlx#show mstp configuration 
mstp name molgen                          
mstp instance 0  vlan 1 to 4090
mstp instance 0 priority 4096
mstp disable ethe 3/1 ethe 8/8 
mstp admin-pt2pt-mac ethe 1/1 to 1/24 ethe 3/1 to 3/24 ethe 5/1 to 5/8 ethe 6/1 to 6/8 ethe 8/1 to 8/8 
mstp start

What is wrong? The behavior or my expectation? :-)

Why PPM_SENDING_RSTP ?  ( "mstp force-migration-check"  doesn't help, btw. )

Thanks

  Donald Buczek

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