Re: [nznog] NZIX OpenFlow adventures phase 2

8 Jan 2013

      Probably getting a little crosstalk between the subject of what are the 
services/products offered (whats desired and what those look like), 
versus how those are actually implemented (SDN versus existing protocols).

Agreed, SDN can be used to make implementing and managing services 
simpler and more flexible (as I said in this and last email).

But WRT complexity below I was questioning why would you want to make 
the IXPs service offerings more complex. i.e. why more features, more 
choices, more bandwidth control, QoS, bilateral VPNs, etc, as opposed to 
just bigger pipe when bigger pipes in NZ are cheap and easy. Unless of 
course you want to be more than an IXP.

On 1/9/2013 2:22 PM, Josh Bailey wrote:
...
I'm interested to hear more about what you mean by complexity?
I've heard of some large layer 2 networks. They are "simple" (aka
"familiar") but also have some operationally "complex" aspects.
For the sake of argument, what is more "complex" about directly
programming a forwarding element to do exacrtly what you want? Why is
that complexity?
On Wed, Jan 9, 2013 at 12:51 PM, Kris Price mailto:nznog(a)punk.co.nz> wrote:
VPLS is not hard, it's pretty simple, assuming you mean RFC4761 or
    RFC4762. It's not necessarily cheap to get good kit for it though.
If you want a Layer 2 fabric that bilateral peering can take place
    on without involvement of the IX, you could build yourself a public
    L2 service using SDN.
You could also have your big scale out router running on the fabric,
    and still do bilateral peering over Layer 2 E-Line services that are
    set up, with the IX presenting an easy to use portal for configuring
    these. I go to the portal and log in and say I want an E-Line to my
    peer X, and X goes in also to say he accepts, and we're both given
    an C-VID to tag our traffic to each other with. Anything I send to
    my port on the IX with that CVID pops out his port with the CVID
    he's given (potentially these are the same at both ends but doesn't
    have to be that way). Then we get billed a little bit extra at the
    end of each month. This is also achievable with SDN. Again it's just
    analogues to existing services, but set up and managed in a
    different, easier to automate way.
What's certainly true though is that the IX can make use of lots of
    those commodity 64x10GE switches, each costing sub 10,000 USD, to
    offer their customers pretty much infinite bandwidth (certainly in
    NZs case, one of these would happily carry all NZ's traffic right?),
    so why add complexity if it isn't needed and bandwidth at an IX can
    be made so cheap? Maybe one reason to go down that path is if you
    want the IX not to be just an *I* exchange but a general Ethernet
    exchange, which certainly might have some merits.
On 1/8/2013 2:20 PM, Sam Russell wrote:
The hard part of VPLS/MPLS/multiple VRFs over MPLS is getting the
        routers to all agree on their view of the world, and having
        one-way LSPs
        can complicate things further. If you have one controller that
        pushes
        out a single unified view of the world to every device, you make
        it a
        lot simpler, and therefore a lot harder to break things.
The current implementation (as I understand) pushes flows out
        pre-emptively - the software RouteFlow syncs the RIB of a
        running linux
        VM to the flow table on the switch
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