5 Replies Latest reply on Jan 28, 2008 6:36 AM by phoffmann

    Peer download not working.

    Leon SupportEmployee

      Sorry for this might be a stupid question. I am trying to compare peer download with Multicast. In the delivery method, under "Bandwidth" section, I checked "Limit remote downloads (per subnet) to one device at a time". I scheduled a task against to two devices at the same subnet.

       

      By setting as above I think one of the client should download the package from the core, and another should download from peer (the first device).

       

      But the result was different with what I think. According to the IIS log file on the core there were records for both clients downloading the package. It looks like this:

      2008-01-25 06:52:57 192.168.0.60 GET /packages/winima80.exe - 80 - 192.168.2.52 1476-LANDeskDownloader 206 0 0

      2008-01-25 06:53:08 192.168.0.60 GET /packages/winima80.exe - 80 - 192.168.2.50 2928-LANDeskDownloader 206 0 0

       

      I am wondering if there is anything I did wrong or some extra steps to do to achieve this.

       

      Thanks,

      Leon

        • 1. Re: Peer download not working.
          Jared Barneck SupportEmployee

          Well, it could be 1) that "Peer download" is not working in your environment.  2) It could be a bug.

           

          "Limit remote downloads to one device at a time" means only one device will download the software at a time.  It does not exactly force peer download.

           

          So to test if Peer Download is even working, place the file in one peer's cache an then do a "Peer download only" delivery.

           

          Also, with "Limit remote downloads to one device at a time", what I have seen is that one machine downloads the package and if it is very fast, a second machine may start downloading from the Core Server when the first machine finishes.  Sometimes it stops partway thru and finishes getting the rest of the file from the peer, but in that case you would still see the web request.

           

          You probably have to use a packet capture to see what is really happening.  Use Wireshark. http://www.wireshark.org/

           

          First find out if Peer download is working. (Sniff with Wireshark while doing this.)

          Second, try slowing it down, by increase the delay between packets when downloading from source so you can see it easier. (Sniff with Wireshark while doing this.)

          Third, if Peer download is working, try using three machines instead of just 2.

          • 2. Re: Peer download not working.
            ProServices

             

            Hi,

             

             

            Just to clarify the above statement "place the file in one peer's cache an then do a "Peer download only" delivery." - I dont think you can just sneek up on a device and put a file in its cache. The cache is tracked in registry, not by searching the file system (This is how the client knows when to flush stuff from cache). f you want to test peer download do a "multicast cache only" delivery of a small package on one machine and then try and deploy on another using the "Peer or cache only" option. Then check the SDClinet.log file to see if it did it from cache.

             

             

            Regards

             

             

            Ian

             

             

            • 3. Re: Peer download not working.
              dportillo SupportEmployee

              Just to clarify the above statement "place the file in one peer's cache an then do a "Peer download only" delivery." - I dont think you can just sneek up on a device and put a file in its cache. The cache is tracked in registry, not by searching the file system (This is how the client knows when to flush stuff from cache)

               

               

               

               

              If you place a file in a client's sdmcache folder and restart the Targeted Multicast service the file's info will be automatically added to the registry.

               

               

              • 4. Re: Peer download not working.
                ProServices

                Thats cool. Thanks for the info

                • 5. Re: Peer download not working.
                  phoffmann SupportEmployee

                  dportillo-s statement is correct.

                   

                  The re-starting of the Targeted Multicast Service on the client will cause the SDMCACHE-maintenance to happen right away (i.e. "What files do I need to delete?" check primarily). As a side-effect of that, the service also checks for NEW files (which it then adds to its registry with the standard retention time, by default 48 hours).

                   

                  Note that this would happen "on its own" too - the TMC-service checks SDMCACHE in 20-minutes odd (I think) intervals for files to be deleted / files that have been added.

                   

                  But the easiest way (short of pushing a file down to a client from a Core) is to just copy it into SDMCACHE and re-start the TMC-service on the client, so that it "knows" that it has got new files.

                   

                  Paul Hoffmann

                  LANDesk EMEA Technical Lead.