Service Access Point

Service Access Point

A Service Access Point or SAP is an identifying label for network endpoints used in OSI networking.

When using the OSI networking layer (CONS or CLNS), the base for constructing an address for a network element is an NSAP address, similar in concept to an IP address. OSI application layer protocols as well as ATM can use Transport (TSAP), Session (SSAP) or Presentation (PSAP) service access points to specify a destination address for a connection. These SAPs consist of NSAP addresses combined with optional transport, session and presentation selectors, which can differentiate at any of the three layers between multiple services at that layer provided by a network element.

The SAP is a conceptual location at which one OSI layer can request the services of another OSI layer. As an example, PD-SAP or PLME-SAP in IEEE 802.15.4 can be mentioned, where the MAC layer requests certain services from the physical layer. Service access points are also used in IEEE 802.2 Logical Link Control in Ethernet and similar data link layer protocols.

The TSAP is an expansion of the NSAP.

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Service Access Point — (auch Dienstzugangspunkt) ist ein Fachbegriff aus der Telekommunikation. Man bezeichnet damit die Schnittstelle zur Interaktion mit einer Kommunikationsschicht an der oberen Grenze selbiger Schicht. Traditionell modelliert man in der… …   Deutsch Wikipedia

  • Service Access Point — (anglicisme abrégé en SAP) ou point d accès au service est un code hexadécimal sur 2 octets contenu dans les trames Ethernet, entre les champs d adresse MAC et le datagramme. principaux SAP: 0x0800 : IPv4 0x86DD : IPv6 0x0806 : ARP …   Wikipédia en Français

  • Service Access Point — Dienstzugangspunkt lt. ISO der Punkt, an dem die n te Entity der n+1 ten Entity ihren Service anbietet …   Acronyms

  • Service Access Point — Dienstzugangspunkt lt. ISO der Punkt, an dem die n te Entity der n+1 ten Entity ihren Service anbietet …   Acronyms von A bis Z

  • service access point identifier —    (SAPI)    Part of the layer 2 (LAPD) address that identifies frames to/from a particular service …   IT glossary of terms, acronyms and abbreviations

  • Network Service Access Point Identifier — For other uses, see NSAPI. A Network (Layer) Service Access Point Identifier (NSAPI), is an identifier used in GPRS (cellular data) networks. It is used to identify a Packet Data Protocol (PDP) context (a unique data session) in the Mobile… …   Wikipedia

  • Network Service Access Point — Ein Network Service Access Point (NSAP) ist nach ITU T X.115 (1995) die Information, die ein Provider eines OSI Network Service benötigt, um einen bestimmten Dienstzugangspunkt zu identifizieren. Gewöhnlich wird damit ein Computer bzw.… …   Deutsch Wikipedia

  • Network Service Access Point —    Abbreviated NSAP. A 20 octet addressing scheme used in Asynchronous Transfer Mode (ATM) networks for private network addresses …   Dictionary of networking

  • Access Point Name — or APN is the name of an access point for GPRS.An access point is: * An Internet network to which a mobile can be connected * A set of settings which are used for that connection * A particular option in a set of settings in a mobile phoneWhen a… …   Wikipedia

  • Access Point Name — est un paramètre du General Packet Radio Service qui identifie le Gateway GPRS Support Node (GGSN) en cours d utilisation, en téléphonie mobile. Portail des télécommunications Catégorie  …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”