Re: [lmap] Data type for Option/Value

[Ron Stana <[e-mail]>]

Juergen,

The reason we want to pass structured data is because we have tests that define hundreds of network paths, and each network path is defined by a group of parameters.  The example in appendix G is good for defining one network path but does not scale to multiple since it only supports the definition of one src/dest pair.

TWAMP is one example of a test that takes multiple network paths.  It has YANG models defined for it: 
https://tools.ietf.org/html/draft-ietf-ippm-twamp-yang-01
https://tools.ietf.org/html/draft-mirsky-ippm-twamp-light-yang-03

Which model is used depends on whether the network path requires special setup steps.  A single test could then consist of one or both of these models.

For these reasons we are using one LMAP id/value option for each of the TWAMP models above.

The example in appendix G requires an extension of the LMAP model.  While I can see that it is a nice way of combining the two models, my understanding is LMAP was trying to prevent the need for customer extensions, especially in this situation where two well-known models are used.

The Appendix F example seems to define the new objects for use both within action/parameter and action/object.  If that understanding is correct, can you explain the difference between using them in the two places?  I didn't see anything in the information model document (version 11) that explained this.

Ron

-----Original Message-----
From: Juergen Schoenwaelder [mailto:[e-mail]] 
Sent: Friday, October 07, 2016 2:24 PM
To: Ron Stana
Cc: [e-mail]; [e-mail]
Subject: Re: [lmap] Data type for Option/Value

On Tue, Sep 27, 2016 at 09:24:34PM +0000, Ron Stana wrote:
> LMAP Team,
> 
> The data type for the option/value in the LMAP YANG model is currently defined as a string.  Our tests use a structured set of input parameters, sometimes mandated by IETF YANG models such as TWAMP and TWAMP Light (see example below) so we currently have to stringify the data which makes it unnecessarily hard to read and requires an extra step before sending and parsing.
> 
> "action":[
> 
>    {
> 
>       "name":"Test-2016-09-27-16:54-action",
> 
>       "task":"twamp-initiator",
> 
>       "option":[
> 
>                  {
> 
>                     "id":"twamp-light",
> 
>                     "value":"{\"ietf-twamp-light:twamp-light\":{\"twamp-light-session-sender\":{\"sender-light-enable\":true,\"test-session\":[{\"session-id\":1,\"test-session-enable\":true,\"packet-padding-size\":425,\"session-authentication-mode\":\"unauthenticated\",\"interval\":10,\"sender-ip\":\"192.168.2.10\",\"sender-udp-port\":50000,\"reflector-ip\":\"192.168.2.20\",\"reflector-udp-port\":50000,\"dscp\":0},{\"session-id\":2,\"test-session-enable\":true,\"packet-padding-size\":41,\"session-authentication-mode\":\"unauthenticated\",\"interval\":20,\"sender-ip\":\"192.168.2.10\",\"sender-udp-port\":50000,\"reflector-ip\":\"192.168.2.20\",\"reflector-udp-port\":50000,\"dscp\":8}]}}}"
> 
>                 }
> 
>       ],

Why do you encode all twamp-light options in a single lmap task option?

> 
>       "destination":[
> 
>                  "Test-2016-09-27-16:54-results-periodic-pm",
> 
>                 "Test-2016-09-27-16:54-results-periodic-rt"
> 
>       ]
> 
>    }
> 
> ]
> 
> 
> 
> Can the value object be changed in the LMAP YANG model so that it can contain another object (i.e. YANG's anyxml object type)?
>

Please take a look at appendix G of draft-ietf-lmap-yang-05.txt for a possible way to do this if plain name/value pairs are not good enough.
Using anydata makes the data really opaque. But the most important aspect, I think, is that LMAP YANG module provides the proper hooks to enable future extensions (via the parameters container).

/js

PS: Note that options are automatically submitted with result reports;
    we should make sure that added structured parameters are also
    contained in result reports (anydata may work generically here
    since the format is implicitely defined).

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <http://www.jacobs-university.de/>