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STP flooding my network...

Discussion in 'Networking Issues' started by progpress, Feb 16, 2006.

  1. progpress

    progpress Guest

    We installed 3 SD216 Linksys 16 port switches and 6 SD208 Linksys 8 Port switches on our network about 10 days ago. On two different occasions, my network has been flooded with Spanning Tree Protocol packets coming from one of these switches, basically bringing all network traffic to a halt.

    Example of one:

    No. Time Source Destination Protocol Info
    11 2006-02-15 17:04:19.401243 Cisco_e3:bb:a2 Spanning-tree-(for-bridges)_00 STP Conf. Root = 32768/00:30:78:e3:b8:00 Cost = 0 Port = 0x8045

    Frame 11 (60 bytes on wire, 60 bytes captured)
    Arrival Time: Feb 15, 2006 17:04:19.401243000
    Time delta from previous packet: 0.000032000 seconds
    Time since reference or first frame: 0.000301000 seconds
    Frame Number: 11
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Protocols in frame: eth:llc:stp
    IEEE 802.3 Ethernet
    Destination: Spanning-tree-(for-bridges)_00 (01:80:c2:00:00:00)
    Source: Cisco_e3:bb:a2 (00:30:78:e3:bb:a2)
    Length: 38
    Trailer: B800804300001400
    Logical-Link Control
    DSAP: Spanning Tree BPDU (0x42)
    IG Bit: Individual
    SSAP: Spanning Tree BPDU (0x42)
    CR Bit: Command
    Control field: U, func=UI (0x03)
    000. 00.. = Command: Unnumbered Information (0x00)
    .... ..11 = Frame type: Unnumbered frame (0x03)
    Spanning Tree Protocol
    Protocol Identifier: Spanning Tree Protocol (0x0000)
    Protocol Version Identifier: Spanning Tree (0)
    BPDU Type: Configuration (0x00)
    BPDU flags: 0x00
    0... .... = Topology Change Acknowledgment: No
    .... ...0 = Topology Change: No
    Root Identifier: 32768 / 00:30:78:e3:b8:00
    Root Path Cost: 0
    Bridge Identifier: 32768 / 00:30:78:e3:b8:00
    Port identifier: 0x8045
    Message Age: 0
    Max Age: 20
    Hello Time: 2
    Forward Delay: 15

    0000 01 80 c2 00 00 00 00 30 78 e3 bb a2 00 26 42 42 .......0x....&BB
    0010 03 00 00 00 00 00 80 00 00 30 78 e3 b8 00 00 00 .........0x.....
    0020 00 00 80 00 00 30 78 e3 b8 00 80 45 00 00 14 00 .....0x....E....
    0030 02 00 0f 00 b8 00 80 43 00 00 14 00 .......C....


    It seemed to happen at random times, unplugging the switches and plugging them back in fixes the problem but what is causing this?

    Thanks.
     
  2. sliderwkw

    sliderwkw Network Guru Member

    any loopback conditions appear?
     

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