intervlan routing issue

Posted on 2009-02-15
Last Modified: 2012-05-06
Dear Experts

site toplogy consists of a router 2821 , core switch 4507R  and access catalyst switches 3550
i need to configure intervlan routing on the core switch , but i have some issues because the core switch is not connected directly to the router, instead , it is connected through one of the access switches which is then connected to the router , currenlt all switches act as a layer 2 swicthes with no routing protocol or vlans configured , my question is

- how do i configure intervlan routing on the core switch braring in mind that the core switch isnot directly connected to the router, instead it is conected to a catalyst 3550 switch which is then connected to the router
- suppose i create a vlan X on the switch , if this site is connected to another site that has the same topology , how do i configure vlanX on site A to see Vlan X on site B , meaning, should it be the same vlan id on both sites or should there be any kind of routing information that should be configred on both routers A and B
- i also wanted to create a vlan that should be seprated from those vlans , meaning that , this vlan should be in a differnt subnet and at the same time , it should take a seprate path to the internet and should also be isoalted from the users at the site , how do i configure this ?
- kindly provide configuration scenarios or kindly view the network diagram of the site topology and advise how to configure such scenario
Question by:oelolemy
    LVL 32

    Expert Comment


    If the 4507 needs to do intervlan routing then you will need to terminate the layer 3 components on that device and add seperate connector nets (links) from the 4507 to the upstream router, I  would remove the access switch and upstream router conecctivity.

    You must migrsatte the layer 3 components to the 4507 from where ever they are now.

    I want to add caution here, from the limited amount of information I have this is what I would do. This does however appear to be a very involved project. This is not difficult if you have done this before however, it could be very complex to someone who has not attempted this type of work before.

    why is that access switch there ? Can you directly connect the 4507 to the router?

    harbor235 ;}

    Author Comment

    in fact, it si impossibe to connect that router to the switch , thea reason that the router is connected to a core switch through a layer 2 switch , is that the router is located in a buiilding which is far away from the core switch and there fore there is no way to connect that  router through a firber optic cable since the fastethernet module supports utp cable only and therefore , the router lan ( fastethernet) is connected to a cisco 3550 gbic via a utp cable and that switch ( whch is actually feeding our engineering building ) is connected to the core switch via a fiber optic cable !
    - is it possible to configure the uplink of the core switch connected to that switch as a routed port and assign an ip address to that interface as if it was connected directly to the router since the access switch acts as a layer 2 switch ?
    LVL 32

    Accepted Solution


    ok, so migrate the L3 components as stated above and create a phyiscal L3 interface on the 4507, create a new vlan on the 3550 dedicated to the new L3 interface on the 4507 and the inside router interface.

    harbor235 ;}

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