From c5b25863dc9033085bc6dfd64bedd7f143d5f4a4 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Wed, 11 Jul 2012 00:58:53 -0700 Subject: [PATCH] FAQ: Add FAQ entry for determining OpenFlow port numbers. I don't understand why, but I've had this question from multiple people recently. Signed-off-by: Ben Pfaff --- FAQ | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/FAQ b/FAQ index a6dd5682..4ad8c439 100644 --- a/FAQ +++ b/FAQ @@ -520,6 +520,33 @@ A: The term "normalization" in the log message means that a flow TCP source port 1234, write "tcp,tp_src=1234", or to match UDP source port 1234, write "udp,tp_src=1234". +Q: How can I figure out the OpenFlow port number for a given port? + +A: The OFPT_FEATURES_REQUEST message requests an OpenFlow switch to + respond with an OFPT_FEATURES_REPLY that, among other information, + includes a mapping between OpenFlow port names and numbers. From a + command prompt, "ovs-ofctl show br0" makes such a request and + prints the response for switch br0. + + The Interface table in the Open vSwitch database also maps OpenFlow + port names to numbers. To print the OpenFlow port number + associated with interface eth0, run: + + ovs-vsctl get Interface eth0 ofport + + You can print the entire mapping with: + + ovs-vsctl -- --columns=name,ofport list Interface + + but the output mixes together interfaces from all bridges in the + database, so it may be confusing if more than one bridge exists. + + In the Open vSwitch database, ofport value -1 means that the + interface could not be created due to an error. (The Open vSwitch + log should indicate the reason.) ofport value [] (the empty set) + means that the interface hasn't been created yet. The latter is + normally an intermittent condition (unless ovs-vswitchd is not + running). Contact ------- -- 2.30.2