W3 Naming Schemes

The format of a hypertext name consists of the name of the namingsub-scheme to be used, then a name in a format particular to thatsubscheme, then an optional anchor identifier within the document.For example, the format is for all internet-based access methods:

scheme : // host.domain:port / path / path # anchor

A suffix # anchor id allows one to refer to a particular anchor withina document.

A suffix ? followed by words separated by + signs allows one to seachan index (see details ).

References from one document to another with a similar name may beabbreviated to a relative name . This imposes certain restrictionson the way that the 'path' is represented.

A special format is used to represent a search on an index . See also:the full BNF description , about escaping illegal characters .

Examples

file://cernvax.cern.ch/usr/lib/WWW/defaut.html#123This is a fully qualified file name, referring to a document in thefile name space of the given internet node, and an imaginary anchor123 within it. #gregThis refers to anchor 'greg' in the same document as that in whichthe name appears.

Naming sub-schemes

Different schemes usually use different protocols on the network.The format of the address after the scheme name is a function of theparticular scheme. In practice, all internet-based schemes have acommon format for the node name and port. Schemes currently definedare as follows, with links to more details.

file: Access is provided to files, using whatever means the browserand/or gateways have to reach files on obscure machines.
news: Access is provided to news articles, and newsgroups, normallyusing the NNTP protocol.
http: Access is provided to any other information using the HTTP searchand retrieve protocol . The internal addressing of the informationsystem is mapped onto a W3 path.
telnet: Access is provided by an interactive telnet session. This isprovided ONLY as an interface to other existing online systems whichcannot or have not been mapped onto the W3 space.
gopher: Access is provided using the 'gopher' protocol. The gopherprotocol is similar to HTTP but uses separate concepts of menus andtext files rather than hypertext.
wais: Access is provided using the WAIS adaptaion of the Z39.50 protocol.
x500: Format to be defined.

Systems (such as WAIS) which are not currently accessed directly beW3 servers may be accessed though gateways, in which case the documentaddress is encoded within the http address of the document in thegateway. Browsers which do not have the ability to use certain protocolsmay (in principle) be configured to automaticaly use certain gatewaysfor certain addressing schemes.

This will allow, for example, simple PC-based clients to follow linksthrough X500 name servers.

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