Hypertext Caching Protocol (abbreviated to HTCP) is used for discovering

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...

caches and cached data, managing sets of HTTP caches and monitoring cache activity. It permits full request and response headers to be used in cache management and expands the domain of cache management to include monitoring a remote cache's additions and deletions, requesting immediate deletions and sending hints about web objects such as the third party locations of cacheable objects or unavailability of web objects.

Features

All multi-

octet Octet may refer to: Music * Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble ** String octet, a piece of music written for eight string instruments *** Octet (Mendelssohn), 1825 compos ...

HTCP protocol elements are transmitted in

network byte order In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most sig ...

. All reserved fields should be set to binary zero by senders and left unexamined by receivers. Headers must be presented with the

CRLF Newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a ...

line termination, as in HTTP. Any

hostname In computer networking, a hostname (archaically nodename) is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication, such as the World Wide Web. Hos ...

s specified should be compatible between sender and receiver, such that if a private naming scheme (such as HOSTS.TXT or NIS) is in use, names depending on such schemes will only be sent to HTCP neighbors who are known to participate in said schemes. Raw addresses (dotted quad

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

, or colon-format

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...

) are universal, as are public

DNS The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to ...

names. Use of private names or addresses will require special operational care. UDP must be supported. HTCP agents must not be isolated from network failures and delays. An HTCP agent should be prepared to act in useful ways when no response is forthcoming, or when responses are delayed or reordered or damaged.

TCP TCP may refer to: Science and technology * Transformer coupled plasma * Tool Center Point, see Robot end effector Computing * Transmission Control Protocol, a fundamental Internet standard * Telephony control protocol, a Bluetooth communication s ...

is optional and is expected to be used only for protocol debugging. The

IANA The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Interne ...

has assigned port 4827 as the standard

and UDP port number for HTCP. An HTCP Message has the following general format: +---------------------+ , HEADER , tells message length and protocol versions +---------------------+ , DATA , HTCP message (varies per major ver. number) +---------------------+ , AUTH , optional authentication for transaction +---------------------+

External links

*{{IETF RFC, 2756, link=no - the

Request for Comments A Request for Comments (RFC) is a publication in a series from the principal technical development and standards-setting bodies for the Internet, most prominently the Internet Engineering Task Force (IETF). An RFC is authored by individuals or g ...

on HTCP Web caching protocol

Features

See also

External links