9 Replies Latest reply on Jun 27, 2013 8:44 AM by cj!

    Multicast Bonjour issues

    dime New Member

      A client has several Apple TVs and other Apple devices that cannot see each other now that we are on the 160.  I there something special I need to turn on to allow that broadcast traffic to hit other wireless clients in the same Vlan?

      This post was the closest I could find... How come Apple Bonjour (Formerly Rendezvous) is unable to locate devices and services that are on the same BSC managed network as as each other?

       

      The two devices trying to find each other are both connected to the same wireless vlan on the same device...

       

      Thanks!

        • Re: Multicast Bonjour issues
          cj! Beta_User

          I'm interested in this question too.  Looking forward to the answer.    In our experience, an iOS device connected to an NV160 AP functions properly with a hard-wired Apple TV.  But we cannot connect to an Apple TV that is also connected via WiFi with an NV160 AP.

          • Re: Multicast Bonjour issues
            levi Employee

            dime:

             

            Thank you for asking this question in the support community.  Multicast traffic can be problematic for wireless networks as it is a low priority protocol and will be queued at the access point (AP). This is true for all 802.11 technologies. When editing a specific radio on an AP in the web interface, there will be a tab to display advanced settings. Within the advanced settings there are settings for the beacon period (or the command beacon period <time> in the CLI).  Most likely, this setting will need to be changed.

             

            Beacons are sent by the AP to keep the wireless network synchronized. The delivery traffic indication message (DTIM) will alert the wireless clients of the presence of broadcast and multicast traffic. After the DTIM, the access point will send the broadcast/multicast traffic. These settings are set to 100ms for the beacon interval and 1 for the DTIM by default. In other words, the default settings are to send broadcast/multicast traffic every 100ms. Often times this will cause the application to fail as it appears there is no connectivity.

             

            Beacon frames are associated with some overhead, which decreases the throughput of the wireless network. The higher the beacon period, the fewer number of beacons sent, thus reducing overhead and increasing throughput on the network. However, fewer beacons can cause a delay in the association process because stations scanning for available access points (APs) may miss the beacons.  The DTIM is set to one, so the unit will send an indicator with each beacon. The beacon interval however is default at 100ms, so that would be the first thing to modify (lower). I do not recommend configuring this for less than than 50ms though. Otherwise the AP doesn't have enough capabilities to service very many clients. Essentially the lower the interval, the less clients that AP can properly support.

             

            Levi

              • Re: Multicast Bonjour issues
                dime New Member

                levi:

                 

                Ok, I've changed the DTIM value to 60ms.  Is there a ball park idea of how many clients it can support at what DTIM value?  We were previously on a Cisco WAP4410 before upgrading to the NV160 and it didn't have these issues.  Is there something special it was doing?

                I'll update with the result tomorrow when the devices are back to work.

                 

                Thanks!