Site Links and Physical WAN Links

Discussion in 'MCSE' started by Guest, Mar 20, 2005.

  1. Guest

    Guest Guest

    Currently studying for the 70-219 exam. I have read and understood the
    theoretical stuff on sites and site links. What I have failed to grasp
    though is how you associate a site link with an actual physical WAN Link.


    Lets say I have a single domain that is spread across 2 sites. Each site is
    on a separate subnet and 2 WAN links exist between the 2 sites. My preferred
    WAN link is an ADSL connection and I have a backup dialup or ISDN connection.

    I setup 2 site links in AD Sites and Services. For the dialup connection, I
    leave the cost at the default of 100 and for the ADSL link, I lower the cost
    to 50 so that it will be used in preference. I create the subnets, allocate
    DC to each site, etc, etc.

    Now although I have setup the 2 site links, how do I communicate the fact
    that one relates to my ADSL link and the other relates to my backup dialup
    link? There is nowwhere that I can see that allows me to associate my link
    with my physical WAN connections/equipment, either by assigning IP of Default
    Gateway, or specifying a dial-up type connection, etc.

    How, therefore, do the site links created know which physical or actual WAN
    link to use?

    Thanks in Advance
    Guest, Mar 20, 2005
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  2. Guest

    Guest Guest

    Guest, Mar 21, 2005
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  3. Guest

    Guest Guest

    Thanks for the link csr_tech100. I have read it but it still does not fully
    explain the deeper workings.

    I am clear that you use a site link to represent a WAN link and that if you
    have more than one WAN link between two sites you can assign a cost to the
    link to use one link in preference over the other. However, what the article
    and other articles i have read fail to explain is how does AD know that when
    I create a link that it releates to a specific WAN device used to connect the
    two sites.

    I am assuming that because when you define a site, part of that process is
    to define the subnet(s) that exist within the site and therefore the KCC can
    use this information to work out routes to get to the remote site. If there
    is only one WAN device then it would use it's routing tables to send traffic
    across the link. However, if a second device is available, how does it
    choose which device to use if they both contains routes to the remote site?

    Of course, in defining the site links you would have assigned a cost to each
    link but there still does not appear to be a way to associate the higher cost
    link with your backup WAN device and the lower cost link with your primary
    WAN device, and it is this aspect that I do not fully understand the logic
    Guest, Mar 22, 2005
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