switch packets going out too many ports

Discussion in 'Computing and Networks' started by eeabe, Oct 16, 2015.

  1. eeabe

    Thread Starter Member

    Nov 30, 2013
    59
    9
    Hi all,

    I'm developing a custom embedded system, where multiple client boards are connected to an 8 port Gigabit switch via 100Mbit Ethernet, and then one of the switch ports goes to a PC at 1Gbit speed. The idea is to have each client sending about 90Mbps, and have the PC receive all of the data over the Gbit line. I believe a typical Gbit switch should be able to do this.

    I'm just starting to test, and I find that when data is sent from a client to the PC, only the client port and the PC port activity LEDs flash on the switch. However, when an ACK comes back or I send data from the PC to one client, all of the ports flash activity as if the switch doesn't know who is connected to which port. I'm using wireshark to correlate the activity to the flashes.

    The PC has IP Address 192.168.1.1, and the embedded clients are 192.168.1.51, .52, .53, etc. The embedded boards are using a Wiznet W5300, and I create a bogus MAC address for each one, but each one is unique. I'm using a LinksKey LKS-SG9P8 switch.

    Any thoughts as to why the switch is pushing the messages intended for 192.168.1.51 out to everyone else?

    Thanks.
     
  2. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    eeabe likes this.
  3. eeabe

    Thread Starter Member

    Nov 30, 2013
    59
    9
    It is all done with TCP. There is not any multicast or broadcast. The embedded "client" boards are actually run as TCP servers. The PC software opens up sockets on each board, and then the board pushes data over that TCP socket.
     
  4. eeabe

    Thread Starter Member

    Nov 30, 2013
    59
    9
    Actually, your link has provided the clue I needed. The fake MAC address range I chose uses the multicast bit setting. I will change that bit to a zero and see how that works. Thank you!
     
  5. eetech00

    Active Member

    Jun 8, 2013
    648
    110
    IP cannot function without broadcasts.
     
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