[ovs-discuss] Does ovs will forward lldp once receive it

Ben Pfaff blp at nicira.com
Wed Apr 15 03:15:59 UTC 2015

On Wed, Apr 15, 2015 at 10:45:59AM +0800, Vinllen Chen wrote:
>     I have three question about the lldp packets:
> 1. Does the ovs will forward lldp once receive it
> 2. Does the ovs will send lldp packet to other host or controller or ovs
> 3. Does the ovs will receive lldp reply after sending it

It depends on how you configure OVS.  ovs-vswitchd.conf.db(5) says:

       other_config : forward-bpdu: optional string, either true or false
              Controls forwarding of BPDUs and other  network  control  frames
              when  NORMAL  action  is  invoked.  When this option is false or
              unset, frames with reserved Ethernet addresses (see table below)
              will  not  be  forwarded.  When this option is true, such frames
              will not be treated specially.

              The above general rule has the following exceptions:

              ·      If STP is enabled on the bridge (see the stp_enable  col‐
                     umn  in  the  Bridge  table),  the  bridge  processes all
                     received STP packets and never passes them to OpenFlow or
                     forwards  them.   This is true even if STP is disabled on
                     an individual port.

              ·      If LLDP is enabled on an interface (see the  lldp  column
                     in the Interface table), the interface processes received
                     LLDP packets and never passes them to  OpenFlow  or  for‐
                     wards them.

              Set this option to true if the Open vSwitch bridge connects dif‐
              ferent Ethernet networks and is not configured to participate in

              This  option  affects packets with the following destination MAC

                     IEEE 802.1D Spanning Tree Protocol (STP).

                     IEEE Pause frame.

                     Other reserved protocols.

                     Extreme Discovery Protocol (EDP).

              00:e0:2b:00:00:04 and 00:e0:2b:00:00:06
                     Ethernet Automatic Protection Switching (EAPS).

                     Cisco Discovery Protocol (CDP),  VLAN  Trunking  Protocol
                     (VTP),  Dynamic Trunking Protocol (DTP), Port Aggregation
                     Protocol (PAgP), and others.

                     Cisco Shared Spanning Tree Protocol PVSTP+.

                     Cisco STP Uplink Fast.

                     Cisco Inter Switch Link.

                     Cisco CFM.

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