[Nsi-wg] Identifiers

Wed Jun 13 09:47:14 EDT 2012

Hi,

That's a very long reply which I'll take as support for option 2, define a new subnamespace for NSI.

I will respond to your questions in another thread.

Jeroen.

On 13 Jun 2012, at 15:38, Jerry Sobieski wrote:

> Hi Jeroen et al-
> 
> First a minor nit:  the current NSI form is "urn:ogf:network:stp:<networkname>:<local part>" .  I.e. there is no "opaque" multilevel subspace under the <networkname> component in STPs.
> 
> More importantly, Our desire is to develop a naming convention that is compatible with both NML *and* NSI - so it may be that we need to modify the NML naming convention instead (or also)... we need to look at both.  so keep an open mind how this is best reconciled.
> 
> Step 1.) It seems to me the preliminary issue to be resolved is the actual object mappings.   We have had some preliminary discussion on this that I think poses a good starting point...
> 
> Step 2) Then we need to develop some NML topology examples that replicate the current NSI topologies.  This will provide concrete examples of how the existing [working] topology constructs will be represented in NML.
> 
> Step 3) Then we need to analyze how NSI would work processing these new NML examples, and where it breaks.   And we resolve those issues by changing the NML construct, or by changing the NSI functionality - or a combination of both.
> 
> A basic question occurs to me:  Why do names need to be consistent within NSI and NML?   What breaks if NSI maintains its current naming scheme?
> 
> The NSI protocol needs to be able to map an STP to its home NSI network.  The current NSI CS 1.1 specification describes the two-tuple <networkid>:<localid> STP name implemented as a URN.   It stipulates that the home network is identified by the network name portion found in the STP reference.
> 
> Due to the current dtox topology that is informaly being used by the NSI implementations, the network associated with an STP can also be found by looking up the STP in the topology DB and linking to the NSI Network object.   THis works fine, but to be clear - it is an artifact of the dtox topology, not NSI standard.   Thus the lookup mechanism may not be used or even work in all NSI implementations.  Thus we need to maintain the two-tuple NSI STP.   ...but this could be encoded in a URN an other ways...
> 
> My concern with the lookup mechanism is that it requires STPs be present in the topology db in order to determine which network they belong to.   Implicitly, this requires all STPs to be advertised in the global topology.  Indeed, this means *_/all/_* STPs- including simple end system STPs that are not members of any SDP.   However,  NSI CS does not require any topological knowledge of simple STPs - NSI only needs to know in which network an STP resides and any adjacencies to that network to choose the egress point.    This is sufficient to segment the request and to perform path finding.    Thus there is no current requirement for ALL STPs to be announced - only those that are part of an SDP (the adjacencies.)
> 
> One can imagine that the simple end system STPs will out number SDPs in most networks - probably by orders of magnitude (consider how a campus/data center might fanout one or two WAN links to hundreds or thousands of possible end systems.)  Given the number of virtual endpoints we will have globally - even with a compact syntactic enumeration of STPs - this amounts to a significant(!) amount of topology data that is not strictly necessary and will only rarely be referenced.
> 
> A more efficient system would simply announce NSI Networks and their adjacencies (SDPs).   All STP references would implicitly resolve to the network contained in their name.    Thus a user could specify a STP that he knows is available locally, but which had not been announced to the world, and the NSAs will successfully segment and reserve the connection.
> 
> I believe the NSI hierarchical two-tuple <networkid>:<localid> must be maintained as we reconcile the NML form to NSI.   I think this will prove high useful in both path finding and topology distribution.
> 
> It seems to me the <DNS> requirement for the NML name could be relaxed slightly to be a bit more flexible for NSI network name requirements without undue harm to NML.
> 
> I suggest that there is no need to name STPs with a year component - this should be removed.   (Why is it even required for NML?)
> 
> I actually think I like the possbly multi-level <opaque part> in the NML spec if we make some stipulations about its construction for STP names.
> 
> I pose for discussion the prospect of a subspace - either ...:ogf:network:nsi: , or a sibling ...:ogf:nsi:  that we could use to identify specific NSI names.   Could these maybe be used to reference NML objects directly or indirectly?  THus allowing NSI to maintain its current naming structure under a different subspace....?
> 
> As a related issue, we also need to decide what that distribution process ought to be.
> 
> Thoughts?
> Jerry
> 
> 
> 
> 
> 
> On 6/12/12 9:05 AM, Jeroen van der Ham wrote:
>> Hi,
>> 
>> We need to take a decision regarding the identifiers used for STPs and other elements.
>> 
>> The NML-WG has taken upon itself to register the urn:ogf:network subnamespace, and to make it available for the identification of network resources. The group is currently writing a document describing how that should be used. The current accepted proposal is the following form:
>> 
>> urn:ogf:network:example.com:2012:opaque:part
>> 
>> So after the urn:ogf:network part comes the DNS name of the organisation defining the identifier, followed by the four digit year in which the identifier was created, followed by a local part.
>> 
>> The current Automated GOLE uses identifiers of the form below, which is not compatible:
>> 
>> urn:ogf:network:stp:example.ets:opaque:part
>> 
>> 
>> We have a couple of options going forward:
>> 
>> - use identifiers following NML-WG standard
>> 	a) allow domain owners free form in the opaque part
>> 	b) define that opaque part should begin with "stp:"
>> - try to register a different urng:ogf subnamespace
>> 
>> Note that the last option is not that simple. We have to propose a scheme that will ensure indefinite uniqueness, which would probably be something very closely resembling the NML-WG scheme.
>> 
>> Jeroen.
>> 
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