Re: [Ibnemo] Policies and Intent-Based Networking

[Laurent Ciavaglia <[e-mail]>]

Dear Sue, all,

Please see inline...


On 05/10/2015 20:57, Susan Hares wrote:
>
> Laurent:
>
> I agree that the important part of this discussion is:
>
> a)At which level of abstraction we start (end-user level,  
> administrator for network),
>
> b)At which level the “end-systems) operate – “user end-systems” or 
> “routers that provide entry to network”,
>
> c)What mechanisms exist to translate from a) starting abstraction to 
> b) ending abstraction.
>
> In earlier discussions, we simply looked at the end user as (a) and 
> the router in a large network as (b).    Do you think this is the 
> right place to start?
>
It is surely good enough to start with network operator/administrator 
and routers in a large network as policy "end points".
My initial comment was more to stress the levels of _abstraction_ 
considered: if the policy entry point is quite abstract (cf previous 
policy example) and the policy exit point understands "only" low level 
commands, then the mechanism(s) in between will have to cope with such 
"distance" between the policy end points, ensuring the continuum of the 
policy from the top to the bottom levels.
The main challenge is thus to identify in the defined policy what are 
the informational elements (here the modeling is key), these elements 
shall then be interpreted (semantics/ontology come to mind), and finally 
translated in a format understandable by the next element in the policy 
chain.
We have defined such mechanisms for policy continuum in a recent 
research project (www.univerself-project.eu), applied to autonomic 
networking.

Best regards, Laurent.



> Thanks for the insight,
>
> Sue
>
> *From:*Ibnemo [mailto:[e-mail]] *On Behalf Of *Laurent 
> Ciavaglia
> *Sent:* Monday, October 05, 2015 11:36 AM
> *To:* PEDRO ANDRES ARANDA GUTIERREZ; Susan Hares; [e-mail]
> *Subject:* Re: [Ibnemo] Policies and Intent-Based Networking
>
> Hello,
>
> My naive opinion on the topic would be as follows:
>     -Can all policies be expressed as an Intent?
>      Yes, in the sense that Intent is the "mother" of all policies; 
> this is what the user initially wants the system to achieve.
>
>     -Should all policies be expressed as Intent?
>      Not necessarily. Systems limitations and complexity make it more 
> simple/direct to write a low-level policy/command (i.e. what the 
> majority of policy-based systems does).
>
> A key, hidden point is the policy continuum:
>     1)-at which level of abstraction the policy starts,
>     2)-which level of abstraction the end systems (those receiving the 
> policy) "understand" (the level of support may be non-uniform),
>     3)-what mechanisms exist to translate from 1) to 2), taking into 
> account possible intermediate levels/layers (e.g. user or service 
> level, network level, function level, protocol level, resource level..)
>
> Wrt. Sue's example, I would see an intent-policy defined as: "Steer 
> customer traffic to relevant customer gateway, and all other traffic 
> to default (Internet) gateway." (i.e. the "system" will have to figure 
> out how to understand and translate different customers, what are the 
> right gateways, etc.)
>
> HTH, best regards, Laurent.
>
> On 05/10/2015 16:49, PEDRO ANDRES ARANDA GUTIERREZ wrote:
>
>     Hi Sue,
>
>     Thanks for clarifying…this is a good food for thought. Answers inline…
>
>     /PA
>
>     *De: *Sue Hares
>     *Fecha: *lunes, 5 de octubre de 2015, 14:49
>     *Para: *"[e-mail] <mailto:[e-mail]>"
>     *CC: *'Zhoutianran', "'Bert Wijnen (IETF)'", paag
>     *Asunto: *Policies and Intent-Based Networking
>
>         Hi all:
>
>         Can all policies be expressed an Intent?
>
>     OK, then we end up with something we didn’t quite like/agree upon
>     in Prague: there are different players with different interests
>     and background. Therefore, there will be different intents (scoped
>     by the actor’s view of the world) and maybe different ways of
>     expressing intent, depending on the user’s background.
>
>         I’m trying to determine what policies can or cannot be
>         expressed. Any example would be helpful.
>
>         Here’s three policies I’d like to discuss:
>
>         1)Traffic flow policies
>
>         2)BGP policies for route flow
>
>         3)Policy filters controlling routes,
>
>         I’m working on the I2RS extensions for Filter-Based RIB and
>         BGP (normal and flow filters).    The I2RS Filter-based RIB
>         allow for policies for routing (forwarding a layer 3) to be
>         associated with a set of interfaces.  For example,
>
>         Forwarding filter 1:  128.2/16 nexthop 128.2.1.1
>
>         Forwarding filters 2:   128.5.1/24 nexthop 128.2.1.2
>
>         And the rest get forwarded to the default RIB which
>
>                           128/8 nexthop 128.2.1.3
>
>         The intent  is that customer 1 has 128.2/16, and customer 2
>         has 128.5.1/24.   This node links to these VPNs via 128.2.1.1
>         (customer1), and 128.2.1.2 (customer 3). All other traffic
>         goes to the Internet.
>
>         How do I link this to the normal example of Intent?   Can we
>         render intent down to this level or should I be using a higher
>         level?
>
>     Let me try a hands-on in NEMO ;-)
>
>     So we have two LinkModels:
>
>     LinkModel VPN Property IPPrefix:nextHop, IPPrefix:destinationPrefix;
>
>     LinkModel Internet Property IPPrefix:nextHop;
>
>     And three Links
>
>     Link VPN1 Type VPN Property
>     nextHop:”128.2.1.1/32”, destinationPrefix:”128.2/16” ;
>
>     Link VPN2 Type VPN Property
>     nextHop:”128.2.1.2/32”, destinationPrefix:”128.5.1/24” ;
>
>     Link Default Type Internet Property nextHop:”128.2.1.3/32” ;
>
>     Then we would need 2 NodeModels:
>
>     NodeModel VPNTermination Property IPPrefix:ID, list(IPPrefix):
>     subnets ;
>
>     NodeModel InternetNode Property IPPrefix:ID;
>
>     And then the nodes:
>
>     Node VPNTermination1 Type VPNTermination Property
>     ID:”128.2.1.1/32”, subnets:”128.2/16” ;
>
>     Node VPNTermination2 Type VPNTermination Property
>     ID:”128.2.1.2/32”, subnets:”128.5.1/24” ;
>
>     Node InternetAccess Type InternetNode Property ID:”128.2.1.3/32” ;
>
>     And finally the connections between the nodes:
>
>     Link VPN1 Type VPN EndNodes thisNode,VPNTermination1 ;
>
>     Link VPN2 Type VPN EndNodes thisNode,VPNTermination2 ;
>
>     Link Default Type Internet EndNodes thisNode,InternetAccess ;
>
>     So
>
>     Conclusion no. 1: Yes we can…
>
>     Conclusion no.2: Maybe a bit redundant, right? But this can also
>     be positive, because it would allow for a lot of consistency
>     checking …
>
>     Dunno what others think…
>
>     My .02 cents,
>
>     ---
>
>     Dr. Pedro A. Aranda Gutiérrez
>
>     Technology Exploration -
>
>     Network Innovation & Virtualisation
>
>     email: pedroa d0t aranda At telefonica d0t com
>
>     Telefónica, Investigación y Desarrollo
>
>     C/ Zurbarán,12
>
>     28010 Madrid, Spain
>
>     Fragen sind nicht da, um beantwortet zu werden.
>
>     Fragen sind da, um gestellt zu werden.
>
>     Georg Kreisler
>
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> -- 
>
> Bien cordialement, Best regards,
>
> *Laurent Ciavaglia*
>
> Secure Cloud Networking
>
> Bell Labs | Alcatel Lucent
>
> phone: [phone]
>
> email: [e-mail] 
> <mailto:[e-mail]>
>
> linkedin: laurentciavaglia <http://fr.linkedin.com/in/laurentciavaglia/>
>
> address: Route de Villejust | 91620 Nozay | France
>

-- 

Bien cordialement, Best regards,

*Laurent Ciavaglia*

Secure Cloud Networking

Bell Labs | Alcatel Lucent

phone: [phone]

email: [e-mail] 
<mailto:[e-mail]>

linkedin: laurentciavaglia <http://fr.linkedin.com/in/laurentciavaglia/>

address: Route de Villejust | 91620 Nozay | France