Henning Schulzrinne Dept. of Computer Science Columbia University XCON data modeling – NETCONF, RDF and others draft-schulzrinne-sipping-emergency-req-01 draft-sipping-sos Henning Schulzrinne Dept. of Computer Science Columbia University XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis Executive summary XCON is an instance of a standard problem  avoid the IETF tendency to create one-off protocols excusable a decade ago, recipe for delay now Provide both “semantic” (tightly constrained) and user interface-oriented interface Use XForms where user interface is needed Consider NETCONF for object content manipulation and state retrieval XCON - IETF 62 (March 2005) - Minneapolis

Data representation models Document model structured document RPC model set/get variables Data models RDF NETCONF user-interface oriented XCON - IETF 62 (March 2005) - Minneapolis

“Semantic” description Tightly described set of properties No expectation that user interface would directly correspond to each element No I18N issue  application maps description elements to UI elements in appropriate language translation into other languages done by client and may derive some parts through local policy, rather than user input Well-defined extension policy XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis RDF “Resource Description Framework (RDF) is a language for representing information about resources in the World Wide Web.” describing resources in terms of simple properties and property values XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis RDF, cont’d. W3C RDF primer XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis RDF/XML example <?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:contact="http://www.w3.org/2000/10/swap/pim/contact#"> <contact:Person rdf:about="http://www.w3.org/People/EM/contact#me"> <contact:fullName>Eric Miller</contact:fullName> <contact:mailbox rdf:resource="mailto:em@w3.org"/> <contact:personalTitle>Dr.</contact:personalTitle> </contact:Person> </rdf:RDF> identifies the thing = subject (a URI) property = predicate value = object W3 RDF primer XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis More about RDF Generally, “meta data” RSS is most common usage Also used in Composite Capabilities/Preferences Profile (CC/PP) Has schema-like capability to describe vocabularies Allows trees with nodes and relationships (“is-a”, “has”) XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis RDF: evaluation Good limited parameter-value expressiveness type definition tools available Bad: static document, does not define protocol to get/set elements would need XCAP, XPath or similar XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis NETCONF “The NETCONF protocol defines a simple mechanism through which a network device can be managed, configuration data information can be retrieved, and new configuration data can be uploaded and manipulated. The protocol allows the device to expose a full, formal, application programming interface (API).” http://www.ietf.org/internet-drafts/draft-ietf-netconf-prot-05.txt Defined to run over HTTP, BEEP, UDP, … XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis NETCONF, cont’d. content configuration data operations <get-config> <edit-config> RPC <rpc> <rpc-reply> application protocol BEEP, SSH, SSL XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis NETCONF Data = configuration data = writable  <get-config> state data = read-only, statistics  <get> Leaves privacy and authentication to transport layer Supports Xpath and subtree filtering Supports multiple “data stores” default <running> <candidate> allows incremental update + commit XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis NETCONF RPC <rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <rock-the-house xmlns="http://example.net/rock/1.0"> <zip-code>27606-0100</zip-code> </rock-the-house> </rpc> <rpc-reply message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <some-content> <!-- contents here... --> </some-content> </rpc-reply> XCON - IETF 62 (March 2005) - Minneapolis

NETCONF – subtree filtering <rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <get-config> <source> <running/> </source> <filter type="subtree"> <top xmlns="http://example.com/schema/1.2/config"> <users/> </top> </filter> </get-config> </rpc> XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis NETCONF operations get Retrieve all or part of state + configuration get-config Retrieve all or part of a specified configuration. edit-config merge/create/replace/delete; with possible roll-back copy-config completely replaces configuration delete-config delete a configuration datastore lock lock configuration data store unlock unlock configuration data store close-session graceful termination; releases locks kill-session abort connection XCON - IETF 62 (March 2005) - Minneapolis

NETCONF capabilities advertisement <hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <capabilities> <capability> urn:ietf:params:xml:ns:netconf:base:1.0 </capability> urn:ietf:params:xml:ns:netconf:base:1.0#startup http:/example.net/router/2.3/core#myfeature </capabilities> <session-id>4</session-id> </hello> XCON - IETF 62 (March 2005) - Minneapolis

User-interface oriented Describe suggested rendering on controlling client without client knowing meaning of controls element names are just labels e.g., can’t gateway to other systems based on equivalence user interface can change at any time Element names are text strings, not XML elements no schema verification possible XCON - IETF 62 (March 2005) - Minneapolis

User-interface oriented Client software does not need to understand meaning of terms – just variables and prompts includes necessary prompts and structure needs to be translated into different languages by server Existing work: XForms http://www.w3.org/MarkUp/Forms/2003/xforms-for-html-authors Allows use of CSS to render on variety of devices Allows use of JavaScript for client-side verification Specifies type of control (“selection”), not rendering (“radio button”, “select list”) Suggestion: allow as alternate representation XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis XForms example <h:html xmlns:h="http://www.w3.org/1999/xhtml“ xmlns="http://www.w3.org/2002/xforms"> <h:head> <h:title>Search</h:title> <model> <submission action="http://example.com/search“ method="get" id="s"/> </model> </h:head> <h:body> <h:p> <input ref="q"><label>Find</label></input> <submit submission="s"><label>Go</label></submit> </h:p> </h:body> </h:html> XCON - IETF 62 (March 2005) - Minneapolis

XCON - IETF 62 (March 2005) - Minneapolis Conclusion If desired, XForms provides rich user interaction environment NETCONF provides flexible configuration retrieval mechanism, with extensibility incremental configuration + commit stored configurations (startup, running, candidate) XPath and subtree selection no constraints on configuration content XCON - IETF 62 (March 2005) - Minneapolis