X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=FAQ;h=2912ae335d1abdb9e5ae5e39ff586a7058da7200;hb=f263172c99fd0a72c3f6666ffbaeaab786a3f1a8;hp=4a8a5beecf410a9cc840f86acc6a4dee17820ba1;hpb=99ab7312c17cd4ab603eb6194c50b9f1ef3ca1c9;p=sliver-openvswitch.git diff --git a/FAQ b/FAQ index 4a8a5beec..2912ae335 100644 --- a/FAQ +++ b/FAQ @@ -418,7 +418,11 @@ A: First, why do you want to do this? Two connected bridges are not ports will not work with the userspace datapath, only with the kernel module. -Q: Why are there so many different ways to dump flows? + +Implementation Details +---------------------- + +Q: I hear OVS has a couple of kinds of flows. Can you tell me about them? A: Open vSwitch uses different kinds of flows for different purposes: @@ -434,18 +438,27 @@ A: Open vSwitch uses different kinds of flows for different purposes: about hidden flows.) - The Open vSwitch software switch implementation uses a second - kind of flow internally. These flows, called "exact-match" - or "datapath" or "kernel" flows, do not support wildcards or - priorities and comprise only a single table, which makes them - suitable for caching. OpenFlow flows and exact-match flows + kind of flow internally. These flows, called "datapath" or + "kernel" flows, do not support priorities and comprise only a + single table, which makes them suitable for caching. (Like + OpenFlow flows, datapath flows do support wildcarding, in Open + vSwitch 1.11 and later.) OpenFlow flows and datapath flows also support different actions and number ports differently. - Exact-match flows are an implementation detail that is - subject to change in future versions of Open vSwitch. Even - with the current version of Open vSwitch, hardware switch - implementations do not necessarily use exact-match flows. + Datapath flows are an implementation detail that is subject to + change in future versions of Open vSwitch. Even with the + current version of Open vSwitch, hardware switch + implementations do not necessarily use this architecture. + + Users and controllers directly control only the OpenFlow flow + table. Open vSwitch manages the datapath flow table itself, so + users should not normally be concerned with it. + +Q: Why are there so many different ways to dump flows? - Each of the commands for dumping flows has a different purpose: +A: Open vSwitch has two kinds of flows (see the previous question), so + it has commands with different purposes for dumping each kind of + flow: - "ovs-ofctl dump-flows
" dumps OpenFlow flows, excluding hidden flows. This is the most commonly useful form of flow @@ -456,7 +469,7 @@ A: Open vSwitch uses different kinds of flows for different purposes: including hidden flows. This is occasionally useful for troubleshooting suspected issues with in-band control. - - "ovs-dpctl dump-flows [dp]" dumps the exact-match flow table + - "ovs-dpctl dump-flows [dp]" dumps the datapath flow table entries for a Linux kernel-based datapath. In Open vSwitch 1.10 and later, ovs-vswitchd merges multiple switches into a single datapath, so it will show all the flows on all your @@ -464,8 +477,8 @@ A: Open vSwitch uses different kinds of flows for different purposes: useful for debugging. - "ovs-appctl dpif/dump-flows
", new in Open vSwitch 1.10, - dumps exact-match flows for only the specified bridge, - regardless of the type. + dumps datapath flows for only the specified bridge, regardless + of the type. Performance