Re: [Coin] 答复: Agenda for today

[[e-mail]]

Hi Dave, thanks for your answer and the debate

Re your three characteristics of COIN:
1 functions execute on "inside" nodes
2 (virtual?) secure execution spaces
3 separation of app state vs netops state

I like the two latter abstractions, it's about virtualization really. 
However, I think that these are potential COIN services or methods (like 
RPC), but not defining COIN. In fact, we have items 2 and 3 today with 
the standard layering, just that they do not have incarnations "inside 
the net". So your characterization rests on that item 1, which is back 
to the host or netdevice discussion that I wanted to get rid of. My 
view: I think we have seen the MIDCOM discussion and because the ICMP 
echo function is answered from within the net does not make it COIN, 
even if you wrap in a security perimeter.

Regarding the comment on 'trigger' and your two cases of COPS and RPC 
(good to discuss with examples): Granted, often the very initial trigger 
is from meat space, some human pushing a button, and then a call is made 
into the net. This is not my point. Instead, once that trigger is pulled 
and the event lands inside the net, in-network functions (unknown at 
spec-time) take over control, the control locus moves into the net: The 
triggered function can decide how to react on that event (choice), can 
consult other functions --which can also be outside the net, I should 
note-- and resume (chaining). If control remains outside the net or is 
locked down at COIN spec time - what would be new? I would be happy if 
you see better ways to express this, without reference to 'trigger'.

I'm not familiar with COPS but from what I get from your description is 
that there is no choice, only hardwired (network) functionality, in the 
same way that L2 switches have an IP address, it seems to be classic 
"over-the-net" communication even if it has side effect on net state. 
RPC is a mechanism that can be used over the net as well as from within, 
so it is not characteristic of COIN.

"Late binding": probably "after-spec-time" would have been better in 
order to express that potentially arbitrary code can be thrown at a 
COIN-enabled net. Your compile case and early binding makes sense, COIN 
doesn't have to be "interpreted".

One way to identify new ideas is to probe for their abuse potential, 
which is why I went for the in-net control characteristics: COIN is on 
the right track if it will be faced with in-network RPC storms that can 
only be broken by unplugging all attached devices, or prevented through 
a special COIN resource mgmt framework or compilation guarantees.

> What do people think? which general way of thinking about in-network 
> computing resonates better?

Perhaps there are even more ways of thinking COIN than "interior node" 
vs "in-net control"?

thanks, cft


On Thu, 20 Jun 2019, David R. Oran wrote:

> 
> On 20 Jun 2019, at 11:23, [e-mail] wrote:
>
>       Hi Dirk,
>
>       agreeing on many points, and yes to finding an abstraction. Here is
>       a suggestion (which could help to sharpen the charter?) that
>       focuses onthe control locus instead of hosts, interfaces or tools:
>
>       There is "computing in the network" IFF these conditions hold:
>       - function execution is triggered from within the net (control
>       inside the net)
>       - there is choice as of which function to execute (late binding)
>       - function results are accessible inside the net, can act as
>       triggers (chaining).
> 
> I’m not entirely sure I agree with this. The unstated implication (or at least
> the implication I derive) is that there is an administrative separation between
> the entire that operates and runs application on hosts, and the entity that
> operates and the network and decides what computations run and where. Therefore
> if one does not start from this mental model:
>
>  * 
>
>     It does not seem fundamental to me from where the function execution is
>     triggered.
>
>      +  As an example from a different era and somewhat different problem
>         domain, consider Packetcable Multimedia, which is a QoS resource
>         management protocol for CMTSs based on COPS. In this case an
>         application running on a host sends PCMM function calls to a execution
>         box “inside” the network, which in turn uses COPS to install QoS state
>         in the CMTS. Which part of this is “inside the network”? If you say
>         it’s just the two ends of COPS, then the function of installing QoS
>         state is executed “inside” and the “trigger” is also inside, as the
>         function that derives the COPS stuff from the PCMM calls, is under
>         control of the cable operator and hence “inside” the network. If, on
>         the other hand you start with the PCMM request as the “trigger”, the
>         function execution is invoked from a host “outside” the network.
>      +  Conversely, RICE (or for that matter NFN) method invocation could
>         arrive at an ICN forwarder which has an associated internal module
>         capable of executing the function and returning results. In this case
>         the “trigger” is the original call, possibly from a host “outside” the
>         network being forwarded through ICN routers, and the “execution” is
>         just another piece of method/function code on the router/forwarder and
>         therefore “inside” the network.
>  * 
>
>     Late versus early binding also seems somewhat orthogonal. One can do late
>     binding (as my second example above shows), or quite possibly early binding
>     by setting up a full computation graph statically at the first invocation.
>     In fact, you might even do it at compile time if you have a network with
>     stable and predictable topological and resource structure, as one might for
>     example in a toroidal mesh of TPUs in a Google data center that are all
>     resources “inside” the data center network and not the application hosts
>     executing the ML application.
>
>  * 
>
>     I imagine that chaining (at least the simple forms like SFC or NFV) can’t
>     cross administrative boundaries easily and hence might be constrained to be
>     entirely “inside” the network, but why start from this limitation?
> 
> For me, the more important characteristics of “in network” computing are things
> like:
>
>  * 
>
>     computations are done on devices placed topologically at interior nodes of
>     the network graph, as opposed only at the edges of the graph.
>
>  * 
>
>     The security perimeter is around the computation instance, not a
>     topological boundary of the connectivity graph, hence one can keep an
>     entire distributed computation inside one security perimeter and not have
>     to either leak data or share keys with third parties.
>
>  * 
>
>     Any state kept and/or mutated by the computation is considered application
>     state, not state related to the operation of the basic forwarding and
>     topology maintenance function of the network devices.
>
>       With this definition, plain forwarding is out but also one of your
>       cases where the SDN controller merely configures a multicast tree.
> 
> I think my definitions are somewhat orthogonal to these concerns…
> 
> What do people think? which general way of thinking about in-network computing
> resonates better?
> 
> DaveO.
>
>       best, cft
> 
>
>       On Thu, 20 Jun 2019, Dirk Kutscher wrote:
>
>             Hi,
>
>             More generally, “computing in the network” has the
>             potential to open new perspectives on the relationship
>             of “hosts”, “network” as
>             well as on layers, i.e., required services and
>             functional modularization.
>
>             I don’t think it’s helpful if we constrain ourselves to
>             1990s textbook categories (such as “L3”, “L4”). These
>             categories were not
>             god-given anyway — they just helped in designing
>             systems at a time and explaining them…
>
>             IMO, one of the COIN objectives should be to
>             propose/define new categories for functional
>             composition that help to us to describe
>             the relevant COIN scenarios.
>
>             Just as an example, if we consider a set of distributed
>             data sources and processing/aggregation functions a
>             COIN use case, what
>             would be the “L4” protocol? What would be the
>             “end-to-end” service?
>
>             An example at the other end of the spectrum could be a
>             set of programmable network nodes that get programmed
>             by some SDN controller
>             to achieve a certain packet forwarding behaviour (for
>             example, multicast distribution).
>
>             What abstraction could be useful to describe these two
>             use cases in one framework? (And is there any value in
>             trying to find them?)
>             IMO these are good challenges for COIN.
>
>             And, in that context, SDN frameworks, control protocols
>             (such as OpenFlow), programming languages (such as P4)
>             are IMO just tools
>             that could be useful in one or the other scenario —
>             just like execution environments are tools — they
>             should not define the concepts
>             and decomposition categories we talk about here.
>
>             Summarizing, I agree to DirkT that COIN should go
>             beyond programmable routing and forwarding, and when
>             doing that, we have to
>             rethink traditional definitions of hosts, networks etc.
>
>             Cheers,
>             Dirk
> 
> 
> 
> 
> 
>
>             On 19 Jun 2019, at 17:52, Marie-Jose Montpetit wrote:
>
>             (Chair hat off):I actually agree with Dirk. I would not
>             want to limit computing to the routing and forwarding.
>             We have
>             discussed meta data processing in the past for example.
>             And host is generic enough.
>
>             mjm
>             Marie-Jose Montpetit, Ph.D.
>             [e-mail]
>             [e-mail]
>             [phone]
>             @SocialTVMIT
> 
> 
>
>             On Jun 19, 2019, at 11:49 AM, Dirk Trossen
>             <[e-mail]> wrote:
>
>             Hemant
>
>             I was under the impression the RG would target
>             computing in networks (COIN). I didn't see this as
>             limited to essentially
>             programmable routing and forwarding. If indeed the
>             group targets the intersection of computing and
>             communication, as
>             expressed early in the charter, the removal of any
>             mentioning of host is rather questionable to me.
>
>             Best
>
>             Dirk
> 
> ______________________________________________________________________________
>             ______________________________________________________
>             From: [e-mail] <[e-mail]>
>             Sent: Wednesday, June 19, 2019 1:02:30 PM
>             To: 'Hejianfei (Jeffrey)'; Dirk Trossen; 'Marie-Jose
>             Montpetit'; [e-mail]
>             Subject: RE: [Coin] 答复: Agenda for today Please see
>             in line below.
> 
> 
>
>             From: Coin <[e-mail]> On Behalf
>             Of Hejianfei (Jeffrey)
>             Sent: Tuesday, June 18, 2019 10:40 PM
>             To: Dirk Trossen <[e-mail]>;
>             Marie-Jose Montpetit
>             <[e-mail]>; [e-mail]
>             Subject: [Coin] 答复: Agenda for today
> 
> 
>
>             Hi Dirk,
> 
> 
>
>             Thank you for your comments for the charter.
>             Marie-Jose, Eve and me discussed these in our bi-weekly
>             co-chair meeting,
>             and the response below (with [JEM]) reflects what we
>             three think. Of course, it is how this GROUP feel and
>             think that
>             decides what this group should do…
> 
> 
>
>             JEM(Jeffrey, Eve, Marie-Jose)
> 
> 
>
>             发件人: Coin [mailto:coin-bounces@irtf..org] 代表 Dirk
>             Trossen
>             发送时间: 2019年6月7日 21:51
>             收件人: Marie-Jose Montpetit
>             <[e-mail]>; [e-mail]
>             主题: Re: [Coin] Agenda for today
> 
> 
>
>             Marie-Jose, all,
> 
> 
>
>             As for the charter, some comments:
>             1.      Item 1 mentions the term ‘network functions’ as
>             the scope of research. Is this limitation to ‘network
>             function’
>             intended?
>             [JEM] After all, we are talking about “in-network”
>             functions. “Network function” is still ok, only if we
>             don’t limit “
>             network function” to simply forwarding.
>             2.      As mentioned in the call, item 2 (use cases) is
>             a method useful not just for requirements analysis
>             (which is
>             solution oriented) but also for scoping of work, i.e.,
>             what is in scope of the RG and what is not
>             [JEM] If we discuss how use cases are related to the
>             scope, we may need to clarify two levels: networks and
>             applications
>             above. We are addressing different sectors of networks,
>             mainly three now: DCN, industrial networks and
>             Edge(with Cloud
>             continuum). And there are different applications
>             related to these three sectors, such as video
>             streaming, immersive
>             AR/VR, autonomous/connected vehicles, industrial IoT.
>             We need to take care of the relationship between
>             network sectors
>             and applications. One potential and ambitious objective
>             is to explore the common architecture or abstraction
>             for these
>             three, but an even less ambitious reason to address all
>             three in this research group is that these sectors can
>             learn
>             from each other. E.g. the metro network connecting
>             edges has the similarity with DCN connecting
>             servers(e.g how to
>             better convey the distributed computing system), while
>             the experience in in-network control from smart factory
>             may be
>             inspiring for the mission critical services in edge
>             networking in smart city. It is up to the group to
>             decide based on
>             their interest if we address all these three or focus
>             some of them. But to us three, all three are related
>             and
>             interesting.
>             3.      Item 2 states “Identify potential benefits to
>             these networks from in-network functionality” which
>             confuses me a
>             bit in terms of ‘these networks’ as a focus here. Item
>             3 does recognize OTOH that we consider placement of
>             compute ‘even
>             in end devices’. My main concern goes back to the
>             feedback I received in the past from people who see
>             ‘the network’
>             ending at the last link to the end device. If we see a
>             continuum of providing services across devices that
>             include end
>             devices as well as ‘in-network resources’ then the
>             benefits are not limited to ‘the network’ only. I
>             suggest simply
>             removing ‘to these networks’ from the statement
>             [JEM] Yes, we think “simply removing ‘to these
>             networks’ from the statement” is fine.
>             4.      I understand item 4 having arisen from the
>             interactions with the transport area but I wonder why
>             we do not
>             include ‘routing’ into the list here, unless we assume
>             ‘transport’ does include ‘routing’. On the other hand,
>             item 3
>             includes ‘new protocol designs’ so it seems that the
>             unique point about item 4 is in fact the security and
>             privacy part
>             so maybe rewording item 4 to “research on new privacy
>             and security mechanisms required to enable in-network
>             compute”
>             would be best?
>             [JEM] Yes,  we agree that  probably moving “transport
>             protocol” to item3 can resolve the ambiguousness. Then
>             the item 3
>             may looks like: “Research on novel architectures,
>             data-plane abstractions and new networking/transport
>             protocols designs
>             to…” The reason behind current text:  networking is
>             layer-2/3, transport is layer-4, so the current item3
>             is emphasize
>             the layer-2/3 as the data plane in the switches and
>             routers, while transport are at the host side. But Dirk
>             is right, it
>             is confusing to separate “ transport” from “ network”.
>             Last question for me to understand the scope: what is a
>             programmable network device? An SDN or P4 switch? Or
>             networked
>             laptop? Or my mobile device? Or all of it? Throughout
>             the charter text, we talk about programmability for
>             ‘devices’,
>             ‘switches’ as well as ‘networks’. Maybe if we answer
>             the question for ‘device’, we can provide good answers
>             to the
>             others?
>             [JEM] A programmable “network device” can be:  a
>             programmable switch, a router with Network Processor
>             Units(NPUs) which
>             is typically also programmable but not as open as a P4
>             switch, a soft-router/switch with X86 or ARM in the
>             context of
>             NFV, or something made of FPGA, and so on.
> 
>
>             [HS] Minor point.  Please
>             see https://github.com/hesingh/p4-info which lists NPU,
>             FPGA, and generic computer as all
>             being programmable using P4.
> 
>
>             Logically we differentiate “network device” from
>             “host”(“the network’ ending at the last link to the end
>             device”) , but
>             physically a network node and a host may be implemented
>             in the same real hardware: these mobile phones/laptops
>             can
>             function as “network nodes” besides “hosts”. This is
>             not what we try to emphasize at this stage, but it is
>             possible.
>             That’s why we state “’even’ in the end-user device” in
>             item 3.
> 
> 
>
>             [HS] When an interface on a router acquires an IP/IPv6
>             address, the interface is a host.  I would elide all
>             mention of
>             host, mobile device, laptop, etc.  Just stick to
>             “computing in network”.  The network may be connecting
>             a laptop, cell
>             phone, router, switch, refrigerator, smart speaker,
>             whatever…
> 
> 
>
>             Hemant
>
>             --
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> 
>
>             -
>
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