Hi, The IETF's NETCONF WG is trying to select a retrieval filter mechanism for use with <get-config> and <get> operations. The fundamental issue is whether to use a subset of the XPath language or whether to define a mechanism based on XML subtree matching. Your comments can help us decide which propsal to choose. Here's the basic NETCONF <get> protocol operation exchange: <rpc message-id="101" xmlns="netconf-uri"> <get> <filter filter-type="filter-uri"> ... filter data ... </filter> </get> </rpc> <rpc-reply message-id="101" xmlns="netconf-uri"> <data> ... XML selected by the filter criteria ... </data> </rpc-reply> There are two options under consideration for the mandatory filter mechanism (i.e., standard values for the 'filter-type' attribute). If we can't get consensus on the mandatory to implement filter, then we will probably make both optional. A) XML sub-tree filtering A mechanism that allows exact match of element and attribute content, as well as the selection of specific subtrees. (This is implemented in Junoscript.) B) Xpath subset A small subset of the Xpath standard that provides essentially the same (or more) filtering functions as the subtree filter. (Note that full implementation of the Xpath 1.0 standard will be optional, and identified by the #xpath capability.) Operator and application programmer preference is really the deciding factor here. Approach (A) uses XML encoding that looks like the data model XML that will be returned in the response. Approach (B) uses an Xpath string encoding in the request, and the corresponding XML is returned in the response. Here are some example requests in both formats, followed by the response that would be returned in both cases. ------------------------------------------------------------------------ - E1) Select the entire <users> sub-tree Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree-uri"> <users xmlns="http://example.com/schema-1"/> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-1"/> t://users </filter> </data> </get> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <users xmlns="http://example.com/schema-1"> <user> <name>root</name> <type>superuser</type> <full-name>Charlie Root</full-name> <company-info> <dept>1</dept> <id>1</id> </company-info> </user> <user> <name>fred</name> <type>admin</type> <full-name>Fred Flintstone</full-name> <company-info> <dept>2</dept> <id>2</id> </company-info> </user> <user> <name>barney</name> <type>admin</type> <full-name>Barney Rubble</full-name> <company-info> <dept>2</dept> <id>3</id> </company-info> </user> </users> </data> </rpc-reply> ------------------------------------------------------------------------ - E2) Select all 'name' elements within the 'users' sub-tree Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree-uri"> <users xmlns="http://example.com/schema-1"> <user> <name/> </user> </users> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-1"> t://users/user/name </filter> </data> </get> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <users xmlns="http://example.com/schema-1"> <user> <name>root</name> </user> <user> <name>fred</name> </user> <user> <name>barney</name> </user> </users> </data> </rpc-reply> ------------------------------------------------------------------------ - E3) One specific <user> entry Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree"> <users xmlns="http://example.com/schema-1"> <user> <name>fred</name> </user> </users> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-1"> t://users/user[name="fred"] </filter> </data> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <users xmlns="http://example.com/schema-1"> <user> <name>fred</name> <type>admin</type> <full-name>Fred Flintstone</full-name> <company-info> <dept>2</dept> <id>2</id> </company-info> </user> </users> </data> </rpc-reply> ------------------------------------------------------------------------ - E4) Specific elements from a specific <user> entry Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree"> <users xmlns="http://example.com/schema-1"> <user> <name>fred</name> <type/> <full-name/> </user> </users> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-1"> t://users/user[name="fred"]/name | t://users/user[name="fred"]/type | t://users/user[name="fred"]/full-name </filter> </data> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <users xmlns="http://example.com/schema-1"> <user> <name>fred</name> <type>admin</type> <full-name>Fred Flintstone</full-name> </user> </users> </data> </rpc-reply> ------------------------------------------------------------------------ - C.7) Multiple sub-trees Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree"> <users xmlns="http://example.com/schema-1"/> <user> <name>root</name> <company-info/> </user> <user> <name>fred</name> <company-info> <id/> </company-info> </user> <user> <name>barney</name> <type>superuser</type> <company-info> <dept/> </company-info> </user> </users> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-1"> t://users/user[name="root"]/company-info | t://users/user[name="fred"]/company-info/id | t://users/user[name="barney" and type="superuser"]/company-info </filter> </data> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <users xmlns="http://example.com/schema-1"/> <user> <name>root</name> <company-info> <dept>1</dept> <id>1</id> </company-info> </user> <user> <name>fred</name> <company-info> <id>2</id> </company-info> </user> </users> </data> </rpc-reply> ------------------------------------------------------------------------ - C.8) Table with attribute naming Request: (A) subtree <rpc message-id="101" xmlns="netconf-uri"> <get> <data> <filter filter-type="subtree"> <t:interfaces xmlns:t="http://example.com/schema-2"/> <t:interface t:ifName="eth0"/> </t:interfaces> </filter> </data> </get> </rpc> (B) xpath <rpc message-id="101" xmlns="netconf-uri"> <data> <filter filter-type="xpath-subset-uri" xmlns:t="http://example.com/schema-2"> t://interfaces/interface/[@ifName="eth0"] </filter> </data> </rpc> Reply: <rpc-reply message-id="101" xmlns="netconf-uri"> <data> <t:interfaces xmlns:t="http://example.com/schema-2"> <t:interface t:ifName="eth0"> <t:ifInOctets>45621</t:ifInOctets> <t:ifOutOctets>774344</t:ifOutOctets> </t:interface> </t:interfaces> </data> </rpc-reply>