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Loop prevention Help Required

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  • Loop prevention Help Required

    I am facing an issue to sort out, which is as under.
    There are 4 (A, B, C, D) ZTE devices connected with Cisco LAN Switch in bus topology mode. like
    LAN Switch 1(3550)<-->A<-->B<-->C<-->D
    All these 4 devices has 4 LAN ports ( 2 Giga and 2 FE). These devices are connected on trunk port with Cisco LAN Switch.
    There are two VLAN on LAN Switch, 1 for Voice and 2 for Data,
    Interface confs with LAN Switch1 to device A are as under
    interface GigabitEthernet0/2
    description Site-A
    switchport trunk encapsulation dot1q
    switchport mode trunk

    Want to create a redundancy between these 4 devices as if the link Between LAN Switch 1 to Device A fails, all the chain goes down. This Bus was created to save the power consumption.

    Another LAN Switch-2(2950) was placed, trunking with LAN Switch 1, and it was connected with last device D, but a loop was created.
    LAN Switch 1<-->A<-->B<-->C<-->D<-->LAN Switch-2
    I tried to resolve it by port-channel on Lan SW-2, but putting the both interface (one with trunking with LAN Switch 1 and other with device D), this didn't resolve the issue as site D got down.

    any help to get out me out by resolving this issue.

  • #2
    Re: Loop prevention Help Required

    Take a look at Spanning-Tree Protocol (STP)

    Taken from the above URL
    The purpose of Spanning Tree is to prevent loops in the LAN and to select the fastest network links, if there are redundant links in the network. In the event that a link in the network goes down, Spanning Tree will failover to the alternate link, if one exists.
    Please remember to award reputation points if you have received good advice.
    I do tend to think 'outside the box' so others may not always share the same views.

    MCITP -W7,
    MCSA+Messaging, CCENT, ICND2 slowly getting around to.