Hi Ilya,
Thank you for the insights.
As suggested, I created a flow rule with in_port=pf0 actions=output:pf1 to
avoid using the default NORMAL action. I also checked the link status of the
bridge port. It was initially down, so I brought it up, but its state then
changed to UNKNOWN.
Despite these changes, I'm still not receiving packets back. Here are some logs
for reference:
:ovs-netdev: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc fq_codel
state UNKNOWN group default qlen 1000
link/ether 62:d6:ea:54:b9:1e brd ff:ff:ff:ff:ff:ff
: br0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc fq_codel state
UNKNOWN group default qlen 1000
link/ether 3a:30:0e:d7:af:4a brd ff:ff:ff:ff:ff:ff
OpenFlow flow dump:
cookie=0x0, duration=350.705s, table=0, n_packets=3188, n_bytes=209110,
in_port=pf0 actions=output:pf1
cookie=0x0, duration=402.852s, table=0, n_packets=23, n_bytes=2616, priority=0
actions=NORMAL
It seems the packets are not returning even with the explicit flow rule. Is
there anything else I should try on the OVS side?
Best regards,
Thenveer
________________________________
From: Ilya Maximets <i.maxim...@ovn.org>
Sent: Wednesday, May 14, 2025 4:18 PM
To: Thenveer Poolakkanni <thenveer.poolakka...@iwave-global.com>;
ovs-discuss@openvswitch.org <ovs-discuss@openvswitch.org>
Cc: Ayshathul Thuhara <ayshathul.thuh...@iwave-global.com>; i.maxim...@ovn.org
<i.maxim...@ovn.org>
Subject: Re: [ovs-discuss] Packet Drop Issue in DPDK-OVS Bridge on Alveo U200
On 5/9/25 6:19 AM, Thenveer Poolakkanni via discuss wrote:
> Hi Team,
>
> I’m currently working with Open vSwitch (OVS) using the DPDK datapath
> on a Alveo U200, and I’ve encountered an issue where packets are not
> being received back on the traffic generator after being transmitted
> by OVS.
>
> Setup Details:
>
> - Traffic Generator:
> - Port 0 → Connected to Alveo U200 pf0
> - Port 1 → Connected to Alveo U200 pf1
> - OVS is running on the Alveo U200 (datapath_type=netdev), and both
> `pf0` and `pf1` are added as DPDK ports to a bridge named `br0`.
>
> OVS Configuration:
> d76b4ea2-df9e-4d2e-8f9d-06210013ffef
> Bridge br0
> datapath_type: netdev
> Port br0
> Interface br0
> type: internal
> Port pf0
> Interface pf0
> type: dpdk
> options: {dpdk-devargs="0000:08:00.0", n_rxq="4",
> n_rxq_desc="1024", n_txq="4", n_txq_desc="1024"}
> Port pf1
> Interface pf1
> type: dpdk
> options: {dpdk-devargs="0000:08:00.1", n_rxq="4",
> n_rxq_desc="1024", n_txq="4", n_txq_desc="1024"}
>
> After sending packets from the traffic generator to `pf0`, here are the stats:
>
> OFPST_PORT reply (xid=0x2): 3 ports
> port LOCAL: rx pkts=0, bytes=0, drop=0, errs=0, frame=0, over=0, crc=0
> tx pkts=0, bytes=0, drop=100, errs=0, coll=0
> port pf0: rx pkts=100, bytes=6000, drop=0, errs=0, frame=?, over=?, crc=?
> tx pkts=0, bytes=0, drop=0, errs=0, coll=?
> port pf1: rx pkts=0, bytes=0, drop=0, errs=0, frame=?, over=?, crc=?
> tx pkts=100, bytes=6000, drop=0, errs=0, coll=?
>
>
> Why are packets being dropped at the `LOCAL` port, and is that affecting
> forwarding?
You're likely sending traffic only in one direction, so the bridge
can't learn where the destination is and broadcasts these packets
to every port on the bridge. The bridge port is probably down, so
packets sent to it a dropped. Broadcasting to kernel interfaces
will significantly affect performance, but your packets should still
arrive just fine on the other port. So, if you don't see them,
the problem is likely with the driver or a card or otherwise outside
of OVS.
To avoid brodcasting you either need to send some traffic in the
opposite direction or stop using the default NORMAL action in your
OpenFlow configuration. A rule like in_port=pf0,actions:pf1 would
just forward everything directly without learning and broadcasting.
Best regards, Ilya Maximets.
_______________________________________________
discuss mailing list
disc...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
