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This site was created as a place to share stories, tips, and troubleshooting help with ShoreTel/Mitel systems. ShoreTel/Mitel is obviously the MOST exciting VoiP platform on the market right now, and we realized there was no centralized place to discuss this platform, but now there is. Please feel free to join and share your experiences.

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  • WAN Link in Backup mode

    Is there a method of preventing the the ST system from placing calls on a WAN when the WAN is in backup mode.(Routing all calls to the PSTN in this case)
    Reason been that in backup mode the bandwidth is a fraction of what it is (apro 1/4) when in normal working mode.
    I have been looking at call admission control bandwidth but this does not take into consideration WAN in Backup mode.

    Any ideas?

  • #2
    How would you expect ShoreTel to automatically know that it is in backup mode? There is no standard automatic way of determining this.

    For the manual way, you should be able to set the admission control bandwidth to 0. IIRC, this will force all calls over the PSTN.


    • #3
      Backup Mode

      Can you describe your connection a bit. Do you normally have a t1 or something, and use ISDN as a backup connection (or a vpn or something else)?


      • #4
        If you have a backup WAN, then it should have a separate routing table. If you're using VLANs then just deny that subnet from going across the backup WAN. If it's a flat subnet just specify the specific IPs. Shoretel should automatically route calls across the local PSTN if the WAN fails.


        • #5
          Going on no information...

          Here is example of really simple firewall filter you could apply to the VLAN interface that the ShoreTel equipment sits on. 192.168.1/24 would be the segment that the Backup WAN link sits on. So any traffic destined for the backup link would be logged and silently discarded.

          filter no-bkup-wan-access {
          term block-wan {
          from {
          destination-address {
          then {


          • #6
            You could also use Policy Based Routing or Source Based Routing on whatever device is making your WAN routing decisions (i.e. redundant connections to a single router, or if you don't have multiple routes in your switch and a router is your next hop).

            This is slightly more elegant to utilize if you have equipment that will support it. Otherwise, ACLs (Cisco) or firewall filters (Juniper) will work.