The Multicast Address Dynamic Client Allocation Protocol (MADCAP) is a

communication protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics (computer scien ...

that allows hosts to request

multicast In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with ...

addresses from a server.

Overview

The Multicast Address Dynamic Client Allocation Protocol (MADCAP) is designed to allow for automatic dynamic assignment of multicast addresses. MADCAP allows for efficient allocation of multicast addresses. This is important for IPv4 which has a small number of multicast addresses available. This is less of a concern with IPv6 multicast. Whereas IPv6 allows for 2¹¹² possible multicast addresses, IPv4 multicast addresses are restricted to only class D Internet addresses (224.0.0.0/4).

Port number In computer networking, a port is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system, a port is a logical construct that identifies a specific ...

2535 is assigned by

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 ...

for use with this protocol. All protocol messages are encapsulated in UDP datagrams. The MADCAP protocol has much in common with

DHCP The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a cli ...

, but they are separate protocols with no common dependencies.

History

MADCAP was originally based on DHCP. Microsoft included MADCAP as part of the DHCP service in

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It was the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RTM), releas ...

. RFC 2730 was published as a proposed networking standard by the

IETF The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

in December 1999. Guidelines for the allocation of IPv6 multicast addresses using MADCAP were published in RFC 3307 in August 2002.

References

External links

Multicast DHCP

Supporting MADCAP
Communications protocols {{Compu-network-stub