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Cisco Core Configuration

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  • Cisco Core Configuration

    Need some advice. Attached is a diagram (brief) of my network. Basically I got 2 4507 (Sup II) switches that will be the core, and 3750 stacks for distribution. I am having trouble deciding how to configure the "inter-core" communication. I want the environnement to be fully redundant, therefore I want the 100 and 200 vlans to be available on both cores, in case on the them crashes. I am using only 2 vlans for simplification purposes, but in reality I have 12 vlans.

    Each vlan interface is configured with an IP address (.1) for that particular segment, and is used as the default gateway for that vlan.

    My question is how do I define my vlans on the core switches, and what do I use as communication between the 4507 to ensure redundancy?

    As an example, my vlan 100 config is this;

    interface vlan100
    ip address
    no ip redirects
    no ip proxy-arp

    Question 1
    If this is configured on core 1, how do I configure core 2 to make this vlan available if something happens to core 1?

    Question 2
    What do I use between the 2 cores? (I have thought of ISL or EIGRP routing, but am not sure)

    Any help will be greatly appreciated
    Attached Files

  • #2
    Re: Cisco Core Configuration

    I manage a similar topology, so I base my recommendations on a live production environment.

    1) use the 2 fiber ports of each sup2 blade and create a 2-gig port channel between the chassis.

    2) enable hsrp (hot standby router protocol) on each svi (vlan) definition.

    3) enable pvst (per vlan spanning tree) on each sup2 card and set the root bridge for each vlan. In my environment, I home voice to one chassis and data to another chassis. By doing so, both gig trunks at the access layer switches are used. Voice takes one gig trunk, data takes the other gig trunk to the core.

    4) Make sure the hsrp active matches the root bridge. (note the priority on standby and spanning-tree statements)

    5) Select a link-state routing protocol for this type of topology. FWIW: I use EIGRP internally on the core and BGP for the wide are network.

    I can post some example configs if needed, but I figured this out by searching for HSRP config, port-channel (etherchannel) config and modifying spanning tree root config examples.


    • #3
      Re: Cisco Core Configuration

      Thanks for the help.


      • #4
        Re: Cisco Core Configuration


        Do you mind posting a sample config of what your talking about?

        I am trying to implement the same setup with 2 - 6500 core switches. I would
        like to implement the HSRP and pvst.

        Thanks for any help.


        • #5
          Re: Cisco Core Configuration


          I will provide you both 4506 and 6500 config very soon .

          Mr.Scowles-I have a question in my mind regarding your mentioned below point

          "use the 2 fiber ports of each sup2 blade and create a 2-gig port channel between the chassis."

          Instead of using two fiber port of each SUP2 we can use simple Gig port of any module which is part of 4506 chasis to make connectivity b/w two 4506 . and we can use HSRP AND STP in this scenrio also .Correct me if i am wrong.

          Please let me know the answer