[ovs-discuss] Bug when disabling flooding on all physical ports

[Niels van Adrichem]

Hello everybody,

Currently I appear to encounter a small bug in the Open vSwitch implementation version  1.4.0+build0 as shipped with Ubuntu 12.04.2 LTS.
Comparable to the spanning_tree module I want to disable flooding on some of the connected ports.
However, when I disable flooding on all physical ports (meaning all ports except the internal port) of a switch, unmatched incoming packets from the internal port are not forwarded to the controller.

I have repeated this behavior in 2 settings:


1)      An open-vswitch instance with 1 internal, and 1 external port. Once flooding is disabled on the external port it does not forward incoming packets from the internal port to the controller.

2)      An open-vswitch instance with 1 internal, and 3 external ports. Once flooding is disabled on all external ports, packets are also not forwarded to the controller, however, if one external port still has flooding enabled, unmatched incoming packets are forwarded to the controller correctly.

I have not yet checked what happens to incoming packets from physical ports, but confirmed on both controller (POX) and using Wireshark packets from the internal port are not forwarded.

Currently I solve the problem by having the controller calculate which ports I want to flood on and then add each port to the actions-list, but I have the feeling it would be nicer to actually use the FLOOD-port for this.
Concluding, does anybody have any ideas on this item, or am I maybe missing out on something here?

For completeness, I am disabling flooding using the following code snippet:

msg = of.ofp_port_mod(port_no = port,
hw_addr = self.connection.ports[port].hw_addr,
config = of.OFPPC_NO_FLOOD,
                mask = of.OFPPC_NO_FLOOD)
self.connection.send(msg)

ovs-ofctl show br-int gives the following output:

OFPT_FEATURES_REPLY (xid=0x1): ver:0x1, dpid:0000010000000006
n_tables:255, n_buffers:256
features: capabilities:0xc7, actions:0xfff
1(eth5): addr:00:0a:e4:14:2b:8d
     config:     NO_FLOOD
     state:      0
     current:    100MB-FD COPPER
     advertised: COPPER
     supported:  10MB-HD 10MB-FD 100MB-HD 100MB-FD 1GB-FD COPPER AUTO_NEG
LOCAL(br-int): addr:00:0a:e4:14:2b:8d
     config:     0
     state:      0
OFPT_GET_CONFIG_REPLY (xid=0x3): frags=normal miss_send_len=0

Best regards, / Met vriendelijke groet,

Niels L.M. van Adrichem
PhD candidate

TU Delft / Network Architectures and Services
Mekelweg 4
2628 CD Delft
Postbus 139
2600 AC Delft
T +31 (0)15 27 81429
M +31 (0)6 234 95 069
E N.l.m.vanadrichem at tudelft.nl<mailto:N.l.m.vanadrichem at tudelft.nl>

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