[ovs-discuss] Due to Mega-flow cache Valid network protocol packets are dropped.Does it expected?

[Farooq Basha]

Hi,

     I am seeing an issue with Mega-flows cache.
  Can some one explain does it behaves as expected by design?

 Issue  Description:

      1.  I have added the following arp-flows using the ovs-ofctl utility.

       ovs-ofctl add-flow test
"in_port=1,arp,arp_tpa=192.168.1.9,actions=local"
  ovs-ofctl add-flow test
"in_port=local,arp,arp_spa=192.168.1.9,actions=output:1"

2. I am sending following arp request packets using IXIA (Traffic
Generator) but i did not see the arp-reply for 192.168.1.9.

    arp_spa=192.168.1.55 to arp_tpa=192.168.1.60
  arp_spa=192.168.1.55 to arp_tpa=192.168.1.57
  arp_spa=192.168.1.55 to arp_tpa=192.168.1.56
  arp_spa=192.168.1.55 to arp_tpa=192.168.1.9

  I have verified the kernel cache flows , it had only 3 flows.

in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.60/0.0.0.17), packets:6, bytes:744,
used:1.596s, actions:drop

in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.57/0.0.0.4), packets:3, bytes:372,
used:1.625s, actions:drop

in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.56/0.0.0.5), packets:0, bytes:0,
used:never, actions:drop
3. I have sent arp request only for 192.1168.1.9 and i could see the arp
reply.
         Following is the cached flow for arp request packet.
in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.9/0.0.0.4), packets:11, bytes:1364,
used:1.820s,           actions:1

4. Later i have forwarded arp request packets for 192.168.1.57,192.168.1.60
and 192.168.1.56..then only two flows are gets added.

in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.60/0.0.0.17), packets:6, bytes:744,
used:1.596s, actions:drop

in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.56/0.0.0.5), packets:0, bytes:0,
used:never, actions:drop
in_port(2),eth(src=00:00:00:00:00:21,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=
192.168.1.55/0.0.0.2,tip=192.168.1.9/0.0.0.4), packets:5, bytes:1364,
used:1.820s, actions:1
It seems either the flow 192.168.1.57 or 192.168.1.9 can be added but not
both.

If the flow 192.168.1.57 was added then arp never resolved for 192.168.1.9
host even though it has valid flow in User space.


(using the OVS 2.4.2 version).


Thanks
Farooq.J
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