I understand what OpenFlow is.
Not sure what you mean exactly, or rather, how it relates to using OpenFlow in an IXP, or really any network with a large number of routes and traffic to all of them.
On 8/01/2013, at 8:55 PM, Josh Bailey
Hi Nathan; Hardware flows != OpenFlow flows. OpenFlow is an API. Some reflection on these statements may suggest an answer. Thanks,
== If you hit the limit of number of flows, what happens? Does it reject the flow, or does it delete older ones to make room for it?
Given there is no default route, what happens if you get a packet that doesn't match a flow? Does it drop it, or punt it to the controller? (ie. is there a default flow to drop)
If it deletes older flows, and punts non-matching packets to the controller, that sounds like there's a potential for really bad performance spikes as you approach the upper limits of the flow table.
If it deletes older flows and drops non-matching packets, then that's worse.
If you simply reject new flows, then that's a bit better, but you've got to make sure that the route reflectors never re-advertise prefixes unless they're installed in to the flow tables successfully, or you drop packets, or punt them to the controller as above.
Some interesting issues to consider!
Agreed re. VPLS/etc. - but you've got to make sure your switches have reliable connectivity to your controller(s). In a network like WIX, that might be hard, not sure.
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