I'm not sufficiently familiar with the " 5G network slicing solution" to talk to john's point; honestly, I think the implementatin strategy is just that, but its still hard graft and sometimes heroic engineering - no matter how people slide it.
just observing the note about SDN tending to centralization
Id' always considered it an error to consider that SDN must be centralised or semi-centralised or ...
While most of the pictures of such structures indicate this, they actually tell a lie; most any (SDN) switch has a local processor etc etc, practically (from my own experience) SDN is about API definitions being open, extensible, and useful; thus, there is the ability to get into the control-plane data-plane interface - and in recent times we have seen the control plane - API plane (north bound interfaces in SDN nomenclature) have been where every Tom, Dick and Harriet have rerolled their own bad form of centralization etc.
The open/extensible/useable/useful API between controller and switch fabric (where I spend most of my care) does not preclude decentralization, nor does it preclude sensible 'core infrastructure' designs - it is only that so many of the first instance of (recent) SDN work seemed to also proclaim they had discovered (Ha!) the advantage of centralised administration as well.
I'd also suggest and wonder if there is a burden for each of these northbound API people (it might be 5g it might be 'funky new CDN' it might be 'some resiliance thingo') is they don't have much awareness of each others efforts and successes. Of course, building upon solid past success rather than rolling-your-own, gets fewer, so-called, Hot publications..... better stop there before my fingers are burnt.
My thoughts of this second.
cheers,
Andrew.
> On 5 Mar 2017, at 13:01, Jon Crowcroft <[log in to unmask]> wrote:
>
>> I'm dubious about 5G network slicing solutions. Why make it a story about
>> SDN and NFV? A solution in search of a problem?
>
> John
>
> indeed - the scale and resilience requirements for such a crucial dimension of the
> service argue strngly against semi-centralised solutions - i know of one massive data center
> failure which was down to the SDN controller&vlan management, and that was a much simpler (and
> localized) problem, which still needed very complex manual access to get the system up again.
>
> the idea that we'd predicate a core critical infrastructure like 5G on the same design mistake
> is daft. - I suppose we could replicate the SDN controllers to every cell tower and then run
> some state machine replica management algorithm, but why not just run some decentralised
> dice&slice scheme in the first place...? what it would look like is actually an interesting
> problem - another bad idea (I've seen in the IETF) is something based on BGP:)
>
> j.
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