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DS810 (DR810) QoS

From: Paul Denning <pauld@mitre.org>
Date: Fri, 19 Jan 2001 17:47:43 -0500
Message-Id: <5.0.2.1.0.20010119172443.00a7f140@mailsrv1.mitre.org>
To: xml-dist-app@w3.org
QoS scenario

An XP Processing Intermediary on the edge of a public network may add XP 
Blocks and handle interfaces to lower layer QoS mechanisms (e.g., RSVP, 
MPLS, DiffServ, COPS Policy info, etc.) for the next hop in the message 
path to the next XP Processing Intermediary.  An XP Block may provide 
information used by the XP Processing Intermediary to determine what QoS to 
select, what Service Level Agreements (SLAs) and what service level 
specifications (SLSs) [1] may apply.

[1] http://www.ist-tequila.org/

Use Case:

This draft use case is intended to clarify requirement R308.

In the spirit of [2], this use case includes XML snippets to help 
illustrate the point.

This scenario provides a non-normative example of having one (or more) XP 
Modules to handle Quality of Serivce (QoS).

The XP Spec would mandate that QoS mechanisms be added as XP-BLOCK.  An 
XP-BLOCK used for QoS shall have one or more <QOS> elements within the 
XP-BLOCK.  Intermediaries can add additional XP-BLOCK's with other QOS 
elements.  The QOS elements within any one XP-BLOCK are inserted by one XP 
processor; an intermediary cannot insert additional QOS elements within an 
existing XP-BLOCK.  (XP-BLOCKS may have digital signatures, so adding 
elements would invalidate the XP-BLOCK.  "Taxonomy" would be a Mandatory 
attribute of the QOS tag.  XP processors that cannot process the QOS 
taxonomy specified shall react as specified in the Policy attribute in the 
<XP-BLOCK> element.  For example, one policy may be to ignore the XP-BLOCK 
and continue.  Another policy may be to stop processing and return an 
XP-error (or transport-specific error?).  Another policy would be to 
continue but return a warning to the XP sender and write to audit log.

<XP-ENVELOPE>
<XP-CORE>
  (stuff)
</XP-CORE>
<XP-BLOCKSET>
<XP-BLOCK Policy="ignore">
<QOS taxonomy=URIxxx> (Should there be a registry of taxonomies URI's like 
IANA, or OMG tags?)
(note UDDI use of categoryBag NAICS, UNSPC, etc.)
<CACHE-CONTROL> (this tag specific to the QoS taxonomy URIxxx identified above)
    (tags within here not defined in XP core)
</CACHE-CONTROL>
<SLA id=xxxx> (this tag specific to the QoS taxonomy URIxxx identified above)
    (tags within here not defined in XP core)
    (Intermediary could use xxxx to lookup SLA)
    (Should XP define an exception if Intermediary does not recognize xxxx?)
</SLA>

</QOS>
<XP-BLOCK>
</XP-BLOCKSET>
</XP-ENVELOPE>

[2] http://www.w3.org/TR/xmlquery-req#section-Use-Cases-for-XML-Queries
Received on Friday, 19 January 2001 17:51:32 GMT

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