[Nsi-wg] Some questions/remarks on the v2 connection wsdl GlobalID

[Inder Monga]

Hi Jerry,

Well the length of your email was lot bigger even than the NSI WS messages
 so it takes time to process and respond ;)

The problem with analogies is that it is an analogy and imperfect by its
nature, but just attacking the analogy rather than focusing on the core
principles does not help resolve the discussion.  The point is the same -
it is not about the an RA having one ID for the connection, but the
connection having one ID. So when you talk about the user having one ID,
and the downstream PA having to walk the tree to aggregate all the
connection IDs to figure out all the IDs for an end-to-end connection, I
don't understand how that interferes or somehow disproves the need for the
global ID. You can walk the tree or use the global-id, mapping of which
every domain in the path maintains, and can share with other repositories
if needed.

The scenarios you describe below of walking the tree successfully
represents the best case - when everything works, but start putting in
reality into the equation and errors into the situation and you can see how
useful the single ID is. In the end, it is not an extra burden on any one
NSA since connection specific IDs exist and are needed, nobody is getting
rid of them. Using your analogy, each sub-tree provider will map its own
connection iD to the Global ID and maintain that mapping in their domain. A
global ID does not force every domain to use it, or rewrite things that hs
been mentioned,  just asks them to maintain that mapping so the end-to-end
service has a single determinate identifier.

Why you may ask? You mention about perfSONAR - that's a good reason, for
most multi-domain stats collection for circuits,  debugging, accounting,
tracking purposes this serves a very useful purpose.Its an optional
parameter. As soon as NSI goes into production, it will prove useful.
AutoGOLE being a demonstration platform does not have the operational
requirements or multi-domain debugging that will be required for a NSI-CS
production service.

Thoughts?
Inder

p.s. Henrik - I haven't ready your follow-on messages, trying to answer in
order.





>
> On 12/6/12 10:22 AM, Inder Monga wrote:
>
>
>  Let me point to Fedex or UPS as an example, a scalable system of packet
> delivery end-to-end.
>
>  a) Scenario with per-hop connection ID as the only way being suggested:
>  If the sending customer, say John, sends a package, he will get a
> tracking ID. Every time a logical point to point delivery happens, a new ID
> is generated. so when the Fedex store sends the package to the local
> warehouse, the local warehouse generates a new ID, and then the plane flies
> to another town and package enters an intermediate warehouse, a new ID is
> generated. Lets assume to make this case consistent with NSI, that there is
> not one company, and each leg is managed by a different administrative
> entity.
>
> If John gives his package to FedEX,...is John then responsible for going
> to the warehouse to get a status, and then to the airfreight depot to get a
> status?  and then to DHL to see if FedEx used them for a portion of the
> trip? and then to UPS? and then to Redball Express, and then try to
> discover which carries in Europe or Asia those guys then handed it off
> to?   No.  Users would get pissed off if FedEx just handed the package to
> another carrier and washed their hands of it.   But this is your example.
> Your example is an intra-domain example.  FedEx uses a single number inside
> their domain only.  Despite their marketing name for it as a "Global
> Tracking Number" they have a single administrative traking system and all
> their systems use it.   And I bet they had to com eup with an NSI analog to
> track shipments acorss different carriers...and those otehr carriers do not
> use FedEx tracking numbers in their systems.
>

OK think about the US post office Global Express Mail - that is not Fedex
and it uses many countries mail service. Don't attack the analogy - please
look at the concept behind it.
Yes, John gives the package to an entity for delivery, and wants to use the
single tracking number from that entity. Not only that, if John shares that
tracking number with the person receiving the package, his secretary or a
colleague, they can all track the package based on that one ID.


>
>  For a user to discover how his package is being shipped - and which
> carriers were subcontracted to do it - the user *still* needs to go to
> FedEx to get the information - and FedEx walks the tree to discover who
> they allocated it to.   And even for their subs - they only get the status
> their subs wish to release based upon the FedEx id they used.
>

You are talking about the Path computation and the path. I am talking about
monitoring and status. Fedex may use their own algorithms to optimize the
subcontract carriers they choose, their subcontract carriers may use their
own tracking numbers, but for the user, only the Fedex tracking number
matters. For the other subcontractors, if given the Fedex ID, they can
figure out the status of that package. They maintain their own mapping of
the global Fedex ID to their own tracking ID. So the user only deals with
one ID. The entities providing service manage the mapping of their own
service IDs to the global ID - it does not need to be shared with the
user.

>
> FedEx acts as the query point for status as well as the point of service -
> and indeed uses its own Tracking number to query independent subcontractors
> or its own internal status.  This is exactly what NSI does in the Query()
> function.  But those subcontractors do not use FedEx numbers for tracking
> their own internal operations.    You look at a package and you will see
> multple tracking information.   THis is largely simplified for FedEx and
> UPS because they are essnetially a centrally managed domain within
> themselves across the globe.   They are a google for shipping. :-)   But
> they are not universal and the FedEx "Global tracking number" is more a
> marketing name - its not a globally unique identifier - except for FedEx.
>

You are just proving my above point. The subcontractors may use their own
tracking numbers but map it to the global fedex number. They maintain the
mapping and do the translation, not the user. The user only deals with one
ID.


>
>  For the customer to track, he has to
>     1) Get the topology of the entire packet delivery, assuming he has
> authorization. That is a chicken and egg problem because he does not know
> which domains or service providers his packet is going to go through as
> Fedex may have many sub-service providers. He can spend months trying to
> figure that out, but maybe his local store can query and try to figure it
> out for him
>
> Exactly - so the user queries the service provider he gave the package to
> - FedEx, and FedEx walks the tree.  Just like NSI.
>

Not really - you mentioned that the user needs to be authorized at each
leaf of the tree to get the status. Not just like NSI. Also, Fedex can use
that global ID and query their subcontractors...the subcontractors use that
one global ID to get status (and may map to their own ID), but the beauty
is not only Fedex but other services or folks can use that ID with the
subcontractor to query sstatus as well.

>     2) Then he has to send a query to try to get the tracking ID from each
> of those service providers.
>
> No - Customer does not do this - Fedex does this.  Just like NSI - you
> send a Query() to the head PA and that agent queries down the service tree
> recursively and rolls up the result.  One stop shopping.
>
>      3) and then he sends a query to each service provider to find out if
> it left origin point of that service provider to the end point of that
> service provider.
>     4) and then maybe he finds out where the delivery is at, if it did get
> delivered and where the problem could have been if it didnt.
>
> Sigh.
>
> When is the last time you told FedEx which transport carriers to use to
> ship your package?   You just tell them where you want it to go.   *They
> decide how to get it there.*  And they assume responsibility for getting
> it there.  Which is why you can then go to *them* to get a valid status.
> If you do not ask them to go end to end, then they will not give you end to
> end status.   If you ask FedEx to just deliver a package to an exporter in
> New York, and tell the exporter to deliver it to Copenhagen,, FedEx will
> have nothing to do with the status of NYC to CPH.   Not their issue.
> Likewise with NSI.   If you give the package to FedEX, you go back to FedEx
> to ask for the status - and FedEx goes out and finds the status from
> however they arranged for it and  rolls it up and presents it to you - even
> if they delegated delivery to another carrier.
>
> If you got a subcontractor's tracking number and asked the sub for a
> status - they could tell you it came from FedEx, even give you a FedEx
> number,  and they can probably even push the query up the stack and query
> FedEx to get the status of the fedEx segment and roll it all up and present
> it to you.   And this is what the detailed Query() does.  (Except the query
> up doesn't work in NSI because we have this crazy replyTo bogsity as our
> sole means to send messages up the service tree.)
>
> You could not use the FedEx tracking number on the UPS system, or DHL, or
> GOD, or any other.    Nor could you use these other carriers tracking
> numbers with FedEx.
>
> This is exactly what we should do with NSI - Let each NSA PA assign their
> own ConnectionID/ReservationID, and let the NSA PA decide how to
> subcontract it.  The RA and PA each assign and exchange their own
> ConnectionIDs as part of the Reserve/Confirm process.  And then if the user
> wants a status - he takes the ConnectionID that he is given and the NSA
> that assigned it, and queries that NSA for the end to end path.   No
> GlobalID required.
>
> You still need to discover the path it took.  You need more than a
> globally unique ID to do this.  You need to know which NSA(s) are on the
> path - the most obvious one is the one that the RA used to start the
> process.   So now we need to encode NSA information in the GID so you know
> where to start.   So even if the GID contains that first NSA in the GID,
> you *still* need to go query that NSA to get a status and the path.    Does
> ESnet want to honor queries from NSAs that it would not otherwise have
> honored a Reservation Request?   If you only honor requests from "trusted"
> NSAs, then remote unknonw NSAs have no choice but to walk the tree to let
> each NSA that successfully estabslihed the reservation ask for the query.
>
> There is no guaranty that the Global ID you have was actualy passed down
> to the NSA you are querying - even if you know for fact that connection
> transits that infrastructure.   Virtualization can hide this information,
> or the GID was not replicated down - maybe because the PA used different
> credentials to progress the connection.   Lots of legitimate reasons why
> the GID is not found.  And lots of ways to screw with the system (for
> instance - what if I deliberately send several requests that use the same
> GID...it doesn't even have to be one from my own namespace as it could be
> one I am simply replicating from a parent RA... )  We have no way of
> validating or verifying the vercity of the global id, so we are just
> sending jibberish for all we know.   The one identifier we know is valid is
> the one each NSA tells us is the segment ID for their portion.  So we
> recurse down the service tree walking these ConnectionIDs and construct a
> valid picture of the path and state.
>
>
>
>  b) Scenario with a Global Connection ID , the way tracking really happens
>
>  The sending customer delivers his package to a store and gets a global
> connection ID.
>
> No.  He gets a tracking ID issued by the particular Carrier that he gave
> the package to.   The Tracking ID is only "global" in the sense that the
> particular carrier uses that tracking number to track a shipment *they* are
> delivering anywhere in the world.   It is not used across *all* carrier's
> systems, nor is it "globally unique" across carriers.
>
>  He comes home and can query against that.
>
> He can only usefully query that tracking number against the carrier that
> took the package.  No one else.
>
>  He can share the global connection ID to whomever he authorizes and they
> can get status on the package,
>
> Third party requesters can still only query the specific Carrier you gave
> the package to if they wish to get a status. A tracking number by itself
> does not indicate the carrier.    You give the tracking number to a
> different carrier - they won't know it from Peter.   So anyone with a
> tracking number *and the carrier that issued it* can indeed get a status
> - from that carrier.   This is not a function of a globally unique
> identifier - this is an authorization policy of that carrier.   A different
> carrier may require you to login to the account that shipped the package.
> And if you gave that number to a friend without telling them which carrier
> it belongs to, your friend is going to go off on a random exhaustive search
> poking that number at every carrier he knows about to see if it happens to
> return a result...and hopefully it is not duplicated in another carrier's
> system and gives him bogus results.  Now think if you had a rogue automated
> agent that was just probing for ESnet circuits in order to tee up a cyber
> attack...like the US did to Iran...
>
> On the other hand, if an arbitrary agent knows a Connection ID (not a GID)
> and the NSA that issued that Conenction ID, and wishes to discover where
> that connection originates, what rights should that agent have to go and
> stalk that connection, or the user who owns it?   Should any agent be able
> to see how much traffic that connection is carrying?  Should any agent be
> able to freely find out if it was explicitly asked to transit ESnet - and
> allowed to do so? and what path it tok thru ESnet?  Or if it explicitly
> avoided CERnet or some other network?   My contention is that these are
> *local policy decisions* and should not be backdoored simply because we
> have legacy software that breaks if we don't grandfather in a weak
> mechanism that was used in the past.   If ESnet wants to let people see
> their circiuts, then lower the security profiles you apply. i.e. unlock the
> door and prop it open, don't make a big hole in the wall next to it.
>
> third party services like Jeroens don't need special authorization for
> every package sent and from every customer (it works now in AutoGOLE
> because there is no security).  It is his package. but in order to cancel
> it he has to provide authorization that only he can (a secure token or cert
> based authentication)
>
> Sure - we can have different authorization rules for reading vs
> writing/modifying status.. we just define different policy rules.  Some can
> be very lax while others very tight.   But we still need to have
> authorization decision points that enforce policy.
>
> But what do you mean "special" authorization.   If he requested a service
> instance, he should be able to query its status with his credentials.  If
> the carrier decides to use internal private policy to make path decisions
> and potentially uses different credentials to make it happen, does Jeroen
> still have rights to know those decisions?   I would contend he does not.
> Authorizing a user's request to transport data at a certain rate, does not
> implicitly mean that the user is entitled to know other aspects about that
> service that were not explicitly part of the request.     At least not by
> default.  Such access needs to be authorized by a policy - even if that
> policy says anyone can do this.     The service was a data transport
> request - as long as the service is meeting that request, why should access
> to the engineering details be likewise available?     If someone else wants
> to query the status of his service instance, the credentials they present
> should be used to allow or disallow it.  Likewise for canceling the
> service.  It has nothing to do with who's package it is - it is a function
> of makng sure the actions performed are authorized - always - by asserting
> the actor's credentials and the action they wish to perform against a
> policy rule.   If you lower the authorization level to ...nothing...  Then
> you are simply saying that you implement a policy where anyone's
> credentials can perform a any function - you don't bypass the authorization
> decision point.
>
> And more importantly - the level of authorization required to perform some
> function is a policy imposed by the administrative body responsible for
> those resources or services.   Just because *you* in ESnet think that this
> information should be easily visible does not mean that NORDUnet feels the
> same way.  And NORDUnet may give you excellent connection service
> performance and reliability...   And just because NORDUnet might allow any
> academic user a great deal of latitude in provisioning services across
> NORDUnet does not mean ESnet will honor a similar policy.
>
> We can all mutually agree to institute very lax policy, but we should not
> bypass the policy decision points or the policy enforcement points.
>
>  Every step of the way, the global connection ID is scanned and recorded.
> Regardless of the administrative provider, there is one consistent ID that
> can track the package and it is easy for him to know where it is.
> Isn't that a much better service interface?
>
> Nope. FedEx simply calls *their *tracking a number a "global tracking
> number".   If I call the NORDUnet Connection ID the "NORDUnet Global
> Tracking ID" ...would you expect it to work in ESnet?   FedEx can impose
> their global tracking number on themselves - across all of their
> international divisions.  But  they can't impose it on the subcontractors.
> Even the little guys use their own tracking number for actual operations,
> and simply correlate the FedEx number with their own.   And they only look
> for the FedEx "GlobalID" when FedEx comes asking....   If those little guys
> also also serve UPS, they map the UPS tracking number to their internal
> system for UPS packages... and track UPS numbers when UPS asks.   And when
> they are simply tracking their own operations - should they use FedEX
> Global ID or the UPS Internaional ID?  Or could they use their own
> number..?
>
>
>
>  The reason for the confusion around GlobalConnectionID (and the name can
> be improved - please suggest and let the group decide), is because it is
> not mandatory. Because of that the "prototype" NSAs don't fill it out.
>
>  We need to approach the standard not as a mechanism we want to be able
> to work properly across *and beyond* the academic networks.  ESnet tends
> to be focused on the US DoE lab requirements - a relatively limited
> horizon.  But NSI is intended to work across a wide array of network - R&E
> networks *AND* commercial networks.  We need to keep this in mind - NSI
> needs to function in other network contexts - often much MUCH larger and
> untrustworthy.   And R&E networks should not be less able to secure
> themselves than commercial networks.  So if we elect to implement a loose
> authorization policy profile - this is fine.   And I agree can be useful in
> these development activities.    But we should not define a field to be
> something we cannot verify.  E.g. if an ID appears in the GID field - what
> happens if it is *NOT* globally unique?
>
> Perhaps what we need is an "options" field in every message.  This is akin
> I guess to what Chin asked about in Oxford but I think that was for just
> reservation request...  So this field would contain arbitrary type-value
> pairs (or maybe TLVs.)  The Options field would be mandatory, but could be
> empty.  The contents are intended to be parameters for non-standard (i.e.
> implementation specific) functionality.    Since these are *optional and
> non-standard* data, the NSI standard should make no rules about how the
> data elements are defined or how they are handled.  NSI should simply state
> how they are formatted within a message.  And I mean *NO* rules about their
> usage - they are non-stanard i.e. "NOT of the standard." (!) so should not
> be required or referenced by any feature in the standard.  The only thing
> that should be placed in the standard is that there is a message field that
> carries 0 or more non-standard parameters.  Since the parameters are
> non-standard, we can not even stipulate when they ought to be replicated by
> aggregators.   It is left to each particualr NSA implementations to
> interpret them or to ignore them altogether.
>
> Thoughts?
> Jerry
>
>
>
>  My $0.02 representing the other side,
>
>  Inder
>
>
>
>
>
> On Thu, Dec 6, 2012 at 4:19 AM, Jerry Sobieski <jerry at nordu.net> wrote:
>
>>  The GlobalID was created at the request of the perfSONAR developers to
>> enable monitoring - how could you determine which segments belonged to a
>> end-to-end connection without each segment being tagged with a Globally
>> unique identifier?    (IMO this was a situation where old ideas and
>> processes die slowly.)
>>
>> The proper way to do this is to just use the ConnectionID and walk the
>> tree - a detailed Query().   The detailed Query() exposes the actual
>> domains along the path that are actually responsible for processing the
>> service request - rather than trying to find just the domains that are
>> carrying the bits (think about virtualized transit domains).   The Query()
>> process provides *authorized access* to this information throughout the
>> service tree, and it provides genuine and reliable associations between the
>> ConnectionIDs assigned at each NSA for its children.   Using GLobalID -
>> without descending the tree - is a scattershot and unreliable means of
>> discovering which segments comprise a reservation, and it bypasses all
>> security policy asserted above.  Bad bad bad.  The Query() command is fully
>> authorized and so completing a detailed query provides all the information
>> about the connection segments belonging to a reservation and does so
>> according to authorization policy along the tree and according to the
>> requesters that actually built (and are paying for and/or are responsible
>> for) the reservation.
>>
>> The only other application of GlobalID that I recall was a batch query
>> possibility (not currently implemented) - the ability to obtain information
>> on a whole batch of unrelated connection segments.  I.e. if my agent wanted
>> to know about all the connections your NSA was servicing then a global ID
>> might provide some correlation with upstream/downstream segments obtained
>> similarly.   Either way, this poses too many security or privacy issues to
>> count...
>>
>> So our compromise was to allow a tag assigned by a RA to be carried along
>> the segmentation tree so that Connections that wanted to be monitored by
>> perfSONAR could be - but it was optional.    For perfSONAR monitoring
>> purposes - this tag needed to be globally unique - thus its moniker.
>>
>> As Vagellis observes - if each NSA in the tree wishes to assert their own
>> GlobalID downward, then the GlobalID from above gets overwritten, or
>> ignored altogether.  (I don't recall - it may be the case that if the GID
>> is present, it was supposed to be replicated down - but this then prevents
>> intermediate aggregator RAs from asserting a GlobalID themselves. )   If we
>> want all GLobalIDs to be carried downward, the field must be able to carry
>> multiple GlobalIDs, possibly from each network along a path (think
>> hop-by-hop "chain" provisioning).  And if the field can carry multiple
>> GLobalIDs, why limit each NSA to only inserting a single globalID?  Why not
>> let each NSA insert multiple tags?   Indeed, is there really any
>> requirement for the tag to be globally unique in some way?     It was only
>> perfSONAR that required a globally unique identifier.
>>
>> Now two years later, I don't know that there has been any perfSONAR tools
>> modified to actually monitor NSI connections, much less to utilize the
>> GlobalID field to do so.    Does any one know?    Are there any other tools
>> that expect/require the GID to be present? or to be globally unique?  (and
>> how easy will it be to break those tools? :-)
>>
>> Given that NSI has the detailed Query() function that reliably and *
>> securely* exposes the end-to-end segmentation, I do not think the
>> GlobalID field is required any more.  Does anyone have
>> continuing/additional reasons for having it?
>>
>> Unless there is a specific and compelling reason to retain the field as a
>> general purpose communications field preserved in the Reservation record, I
>> propose we should deprecate it and simplify the protocol.   As a general
>> practice for standards, we should *NOT* retain it simply "just in
>> case"...to retain it we need a specific and compelling reason to include it
>> that makes it worthwhile for every implementation to support it.  "optional
>> requirements" is a oxymoron.  Eitehr we need it, or we do not.    If we
>> retain the field, then we need to redefine it so that it can carry multiple
>> tags and so those tags can be recognized/parsed by generalized other
>> agents, and the field should be constrained in size (don't want MPG4 movies
>> being carried in the signaling messages.)
>>
>> One last indirectly related note:  The ability of Query() to serve
>> generalized agents -besides the uRA- will rely upon these agents issuing a
>> detailed Query() to an NSA that is NOT the first hop PA at the root of the
>> service tree.  For instance, a NORDUnet perfSONAR agent will see a local
>> Connection ID it needs to monitor - how does it discover which NSA is the
>> first hop?  And should it need to?   Why can't the local agent issue a
>> detailed Query() directly to the local NSA PA - and let the local NSA PA
>> walk it *UP and OVER* in the service tree as well as down the service
>> tree?   This is a "flooding" detailed Query().   The Query() functions the
>> same way as it does now, only that the Query() is passed up to the parent
>> RA as well, and the parent/child link from which the Query() came (if it
>> came from a parent/child NSA in this connection's service tree) is pruned
>> from the recursive flooding - it just gets the result.
>>
>> By tweeking the Query() in this fashion, we enable a much more powerfull
>> ability to manage the reservation.  This will also be an important
>> capability for Notify() functions - an error condition could be flooded to
>> all NSAs in the service tree using a similar flooding model thus being able
>> to notify all NSAs upstream and downstream in the data plane of local
>> interuptions.    Of course, we won't be able to use the current funky WS
>> respondTo process for these upward bound messaging...we'll need a real
>> symmetric session MTL model to do this.   But we already know this.
>>
>> Jerry
>>
>>
>> On 12/6/12 5:06 AM, Jeroen van der Ham wrote:
>>
>> Hi,
>>
>> On 5 Dec 2012, at 18:24, Vangelis Chaniotakis <haniotak at es.net> <haniotak at es.net> wrote:
>>
>>
>>  Oh, speaking of globalreservationid!
>>
>> we're only passing it around and persisting it not doing anything with it AFAICT.
>>
>>
>> - it's supposed to be a way to tie this connection with external services, right?
>> - if so, the name is not quite descriptive of its function
>> - it's also optional, while the name sounds terribly important
>> - why a URI instead of a string? or key-value pair
>> - there's only one of them, why not allow for a set?
>>
>>  It is supposed to be the ID for the global reservation. The aggregator NSA receives a request, generates an ID and uses this global ID to make connection requests to each of the participating NSAs. They generate a connection ID for their segment, but must be able to relate that to the global reservation ID.
>>
>> So yes, it does perform a very important global function :)
>>
>> It is indeed also meant for tieing in to other services. The URN is used to make it very clear that this is a network global reservation ID.
>>
>> Jeroen.
>>
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