Re: [Ibnemo] Policies and Intent-Based Networking

[PEDRO ANDRES ARANDA GUTIERREZ <[e-mail]>]

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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