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To prevent the bridge transmission in Dual MAC Mode

Kanae
Mastermind 9655 points
Other Parts Discussed in Thread: AM3352

Hi all,
When operating in Dual Mac Mode with AM335x
it is set as vlan_member_list = 0x1 of ALE VLAN Table Entry
to prevent transferring packets between port1 and port2.
This setting is that the port0 is only associated VLAN.
Is my understanding correct?

[Status]
-OS: SDKv7 Linux Kernel-3.12.x
-EVM: Custom with AM3352

Best regards,
Kanae

  • 0
    TI__Guru**** 393215 points

    Hi Kanae,

    This post has an excellent description of the CPSW behavior in different modes: http://e2e.ti.com/support/arm/sitara_arm/f/791/p/336582/1174988.aspx#1174988

  • 0 in reply to Biser Gatchev-XID
    Mastermind 9655 points

    Hi Biser,

    Thank you for your quick reply.
    I have checked the post you mentioned.
    So I would like to make sure that the external ports; port1 and port2
    do not transfer packets each other when I configure the dual MAC mode
    and set as vlan_member_list = 0x1 of ALE VLAN Table Entry.
    If not configuring dual MAC mode, the external ports; port1 and port2 transfer
    packets each other.

    Could you please point if my understanding is wrong?

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Guru**** 393215 points

    See section 14.3.2.10.2 in the AM335x TRM Rev. J. What you require is described there.

  • 0 in reply to Biser Gatchev-XID
    Mastermind 9655 points

    Hi Biser,

    Thank you for your suggestion.
    I think my explanation was not enough in my past post.

    When only port 0 is set as vlan_member_list = 0x1 of ALE VLAN Table Entry
    and port 1 and port 2 are not set as vlan member list, the packet transfers operate
    actually as follows.

    [Vlan tagged packet]

    　port0 <-> port1 :vlan packets can transfer.

    　port0 <-> port2: vlan packets can transfer.

    　port1 <-> port2: vlan packets cannot transfer.


    It seems from this result that the transfer operation from port0 to port1/port2
    is effective regardless of vlan member list setting.

    I suppose this is inconsistent with what TRM described in 14.3.2.10.2 Dual Mac Mode.
    =========
    • Configure the Port 1 to Port 0 VLAN

    Add a VLAN Table Entry with ports 0 and 1 as members (clear the flood masks).

    ...
    • Configure the Port 2 to Port 0 VLAN

    Add a VLAN Table Entry with ports 0 and 2 as members (clear the flood masks).
    ===========

    When adding a VLAN Table with ports 0 and 1 as members or ports 0 and 2 as members,
    the packet transfers start from port 2 to port 1.
    This result is also inconsistent with what TRM described in 14.3.2.10.2 Dual Mac Mode.

    That is why I would like to make sure the proper way to prevent transferring packets
    between port1 and port2.  


    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 27720 points

    Kanae,

    Enabling Dual MAC mode will prevent downstream port peering (direct xfer between ports 1&2) by default. I believe this is what you are looking to do.

  • 0 in reply to -DK-
    Mastermind 9655 points

    Hi DK,

    Thank you for your reply.
    I understand there is totally no problem to AM335x H/W function by your reply.
    Our issue to downstream port peering (direct xfer between ports 1&2) must be caused by TI SDK Linux driver.
    The release notes describe “D-01525: In Dual EMAC mode the device will fail to receive a DHCP address from some routers. Use single EMAC mode. This is under investigation.” as a known issue.

    I would like to ask you whether only port 0 is set as vlan_member_list = 0x1 of ALE VLAN Table Entry would be a workaround for this issue, or not?

    Any comments would be appreciated.

    Best regards,
    Kanae