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STP - 5500 HI and 1910 48G

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  • 1.  STP - 5500 HI and 1910 48G

    Posted Mar 21, 2016 08:32 AM

    Hi folks. Good morning.

    I'm here to ask a question about the STP functioning. I have the following topology:

    1 HP 5500 HI 48G as the core switch. (RSTP enable, BPDU guard enable)

    7 HP 1910 48G (STP are disable on all switches. 5 of this 1910 are connected through a BAGG (fibre) of 2 Gb straight to the core switch. One switch 1910 in another room is connected through a single UTP (1 Gb) to the core switch. The last 1910 is on another building connected through an ISP link (100 Mb).

    On the core switch I have the main assets connected as a Domain Controlller, File and Print Server, Backup Server, Tape Library, some web servers, the Firewall, two storages (1 is a NAS, the other storage not).

    When I need to reboot any device connected to the core switch, I lose the connectivity to the core, to the firewal and if Im doing a backup job or a restore job I lost it too. This is the behaviour and this is being a nightmare because if the electricity fails and the topology changes, the LAN does not come back and I need to force a reboot on the core switch.

    Thanks in advance.

    EDIT#1: The LAN connectivity is stablished when the rebooted machine is uprunning again. Before this, no LAN.


  • 2.  RE: STP - 5500 HI and 1910 48G

    Posted Mar 22, 2016 04:32 AM

    What's the 5500 config?  Does it log show events after rebooting an attached host?  What do STP show commands reveal?

  • 3.  RE: STP - 5500 HI and 1910 48G

    Posted Mar 22, 2016 07:42 AM
      |   view attached


    The config file is attached.

    When I reboot a host connected to the core switch the log events register some ARP messages until the device is uprunning again. Like this:

    Mar 22 01:58:07:174 2016 ARP Notification ARP_DUPLICATE_IPADDR_DETECT Detected an IP address conflict. The device with MAC address 74d4-35f0-d723 connected to Bridge-Aggregation4 in VLAN 1 and the device with MAC address 74d4-35f0-d723 connected to GigabitEthernet1/0/26 in VLAN 1 are using the same IP address

    When the device finishes the reboot process the environment works normally again.

    I'm start to think in power on the STP in the other switches, with RSTP mode on, BPDU protection enbale, instance ID 1 for all HP 1910, root type "not set" and bridge priority 32768. And disable all protection type on the core switch ports.

    Thank you.


    zip   703 B 1 version

  • 4.  RE: STP - 5500 HI and 1910 48G

    Posted Mar 22, 2016 11:51 AM

    Seems like something is looping on the network.  Hook up a PC on VLAN1 , and start a sniffer to capture broadcast packets....  (while rebooting your test host)

  • 5.  RE: STP - 5500 HI and 1910 48G

    Posted Mar 22, 2016 01:01 PM

    Ok, I will try to do this today. A question: Can I start to capture (in promiscuous mode) in Wireshark from my machine?

    I need to do this after the job hour. I drawed a little diagram with the STP configs that I want to implement and it is attached in.pdf.

    Do you think that it is a physical or logical loop?

    Thanks in advance.

    EDIT#1: I did a test a few minutes ago with the STP disabled. and the same behaviour happened. The LAN drops and when the reboot process is finished the core switch pings again.

    It's odd, so much odd.