[Nsi-wg] Service Termination Points
Inder Monga
imonga at es.net
Mon Mar 14 11:21:56 CDT 2011
Returning the hop-by-hop capabilities does not necessarily imply walking the tree.
Inder
On Mar 14, 2011, at 7:50 AM, Jerry Sobieski wrote:
> I think we had agreed at GLIF that queries would be (for now) just
> returning the PA's state and the request parameters as-built. That
> there was no walking the tree implied at this time...?
>
> J
>
> On 3/13/11 12:29 PM, John MacAuley wrote:
>> If we remove the hop-by-hop capabilities from the reservation request, do I also remove it from any queries?
>>
>> On 2011-03-13, at 1:06 PM, Chin Guok wrote:
>>
>>> I'm fine just specifying the source and destination in the initial implementation. However I think that as we evolve the protocol, being able to specify "mid-point" STPs will be useful.
>>>
>>> If I recall correctly, the issue was that the end user may not be able to see the "mid-point" STPs and thus is unable to verify the path. However as we start adding other services (i.e. monitoring, etc), lack of visibility may not be an issue.
>>>
>>> - Chin
>>>
>>> --On March 12, 2011 11:51:20 PM -0500 John MacAuley<john.macauley at surfnet.nl> wrote:
>>>
>>>> I am okay not to specify anything other than the source and destination,
>>>> but was this not the whole discussion around not routing traffic through
>>>> certain locations by specifying the route? It resulted in the trust
>>>> discussion.
>>>>
>>>>
>>>> Does anyone else have strong opinions on the topic?
>>>>
>>>>
>>>> John.
>>>>
>>>>
>>>>
>>>>
>>>> On 2011-03-12, at 11:42 PM, Jerry Sobieski wrote:
>>>>
>>>>
>>>> Hi John-
>>>> I know we've had long discussions about path objects. But I am not so
>>>> sure they are necessary...
>>>>
>>>> If we can make two concatenated connections and treat them as one, then
>>>> why do we need to specify loose hops?
>>>> We can instead just issue two reservation requests, right? If so, this
>>>> would substantially simplify the request structure. And so far, I've not
>>>> heard of any use case that multiple reservations would not work for
>>>> transit routing.
>>>>
>>>> ??
>>>>
>>>> Jerry
>>>>
>>>>
>>>> On 3/12/11 10:35 PM, John MacAuley wrote:
>>>>
>>>>
>>>> Taking Jerry's definition and Tomohiro's note not to use domain or
>>>> endpoint I have defined the following three XML schema components:
>>>>
>>>>
>>>>
>>>> • A "Path Object Type" consists of at a minimum an "aSTP" and a
>>>> "zSTP", with an optional ordered list of "STP" defining the path through
>>>> the network.
>>>> • An "STP Type" consisting of a mandatory "Network Id" string and a
>>>> mandatory "Local Id" string that uniquely identify the STP. There is an
>>>> optional "Order" attribute that will only be populated when the STP is
>>>> part of the ordered list.
>>>> • An "STP List Type" that will support both an ordered and unordered
>>>> list of STPs.
>>>>
>>>>
>>>>
>>>> So is does my definition of a Path Object cover what was intended in the
>>>> CS architecture document?
>>>>
>>>>
>>>> <xsd:complexType name="PathObjectType">
>>>> <xsd:sequence>
>>>> <xsd:element name="aSTP" type="tns:StpType" minOccurs="1"
>>>> maxOccurs="1" />
>>>> <xsd:element name="orderedStpList" type="tns:StpListType" />
>>>> <xsd:element name="zSTP" type="tns:StpType" minOccurs="1"
>>>> maxOccurs="1" />
>>>> </xsd:sequence>
>>>> </xsd:complexType>
>>>>
>>>> <xsd:complexType name="StpType">
>>>> <xsd:sequence>
>>>> <xsd:element name="networkId" type="xsd:string" minOccurs="1"
>>>> maxOccurs="1" />
>>>> <xsd:element name="localId" type="xsd:string" minOccurs="1"
>>>> maxOccurs="1" />
>>>> </xsd:sequence>
>>>> <xsd:attribute name="order" type="xsd:integer" />
>>>> </xsd:complexType>
>>>>
>>>> <xsd:complexType name="StpListType">
>>>> <xsd:sequence>
>>>> <xsd:element name="stp" type="tns:StpType" minOccurs="0"
>>>> maxOccurs="unbounded" />
>>>> </xsd:sequence>
>>>> </xsd:complexType>
>>>>
>>>>
>>>>
>>>> On 2011-03-12, at 10:11 PM, Jerry Sobieski wrote:
>>>>
>>>>
>>>> Hi John-
>>>>
>>>> Yes. For NSI I think we can say an STP==endpoint.
>>>>
>>>> I think STPs in the abstract sense may be topological locations other
>>>> than just a port or a VLAN, but for the purposes of NSI v1.0, I think a
>>>> "real STP" is indeed a location in the topology where a connection may
>>>> originate or terminate.
>>>>
>>>> (I note that I used a circular reference in the endpoint definition.
>>>> Apologies. An Endpoint is the physical topological terminus of a
>>>> connection.) I do reserve some flexibility in the abstraction
>>>> however. I think there are ways we can use Service Termination Points to
>>>> indicate larger complexes of topological elements. If folks are
>>>> intersted I will elaborate, but for now, and to be expedient with respect
>>>> to defining ReserveRequest() parameters, I suggest we accept an adequate
>>>> definition and leave additional refinement to later.
>>>>
>>>> Is this helpful?
>>>> Jerry
>>>>
>>>> On 3/12/11 9:57 PM, John MacAuley wrote:
>>>>
>>>> Jerry,
>>>>
>>>>
>>>> So based on your definition below is STP == Endpoint Reference from an
>>>> NSI protocol perspective?
>>>>
>>>> Definitions:
>>>>
>>>> Service Termination Point := 1. An abstract object that represents the
>>>> ingress or egress point of a connection, or the abstract notion of a
>>>> location in a topology where a connection could potentially originate or
>>>> terminate. 2. A real point in a topology where a connection can
>>>> originate or terminate.
>>>>
>>>> Endpoint := In NSI, this is a location within a network that can be used
>>>> as an endpoint for a connection.
>>>>
>>>> Endpoint Reference := a two-tuple consisting of a {<network name>,
>>>> <endpoint name>} . An “endpoint reference” is this tuple, the
>>>> “endpoint” itself is the topological location it identifies.
>>>>
>>>> John.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
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---
Inder Monga
imonga at es.net
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