[j-nsp] Netconf & namespaces

[Phil Shafer]

Phil Mayers writes:
>The fundamental question is: are namespaces used incorrectly all over 
>the place in Netconf?

JUNOS has some namespace issues, suffering from both pre-rfc
implementation problems and attempts to re-use the underlaying
Junoscript XML API code.  PR 826463 is addressing these.

>I've looked at the PyEZ and ncclient code, and basically they seem to 
>take the approach of just throwing away all namespace information. This 
>seems icky to me, and make me wonder if Netconf is going to be another 
>SOAP - so many implementation errors that "interop" ends up being a mess 
>of special casing and workarounds.

Namespaces are a two-edged sword, and while they are great for
telling you _exactly_ what data you are seeing, this exactness
is often painful.

For example, each version of JUNOS uses a unique namespace, and
we publish specific data models (DTDs, XSDs, and soon YANG) for
each specific version.  But a namespace like:

    http://xml.juniper.net/junos/13.3I0/junos

means that an XPath expression (or the XSL script containing it)
would need that specific URI to match, which can be a maintenance
issue.  For SLAX, I replace the version with "*" to make a namespace
that can be used across versions:

    ns junos = "http://xml.juniper.net/junos/*/junos";

This is just an example and is disjoint from the issues in PR 826463,
where we mistakenly put elements from junos in netconf space and
vice versa.

Thanks,
 Phil