Thursday, 29 March 2012

Layer names and number of layers in the literature

The afterward table shows assorted networking models. The amount of layers varies amid three and seven.

Kurose,10 Forouzan 11 Comer,12 Kozierok13 Stallings14 Tanenbaum15 RFC 1122, Internet STD 3 (1989) Cisco Academy16 Mike Padlipsky's 1982 "Arpanet Advertence Model" (RFC 871) OSI model

Five layers Four+one layers Five layers Five layers Four layers Four layers Three layers Seven layers

"Five-layer Internet model" or "TCP/IP agreement suite" "TCP/IP 5-layer advertence model" "TCP/IP model" "TCP/IP 5-layer advertence model" "Internet model" "Internet model" "Arpanet advertence model" ISO model

Application Application Application Application Application Application Application/Process Application

Presentation

Session

Transport Transport Host-to-host or carriage Transport Transport Transport Host-to-host Transport

Network Internet Internet Internet Internet Internetwork Network

Data hotlink Data hotlink (Network interface) Network admission Data hotlink Link Network interface Network interface Data link

Physical (Hardware) Physical Physical Physical

Some of the networking models are from textbooks, which are accessory sources that may abjure the absorbed of RFC 1122 and added IETF primary sources.17

Different authors accept interpreted the RFCs differently, about whether the hotlink band (and the TCP/IP model) covers OSI archetypal band 1 (physical layer) issues, or if a accouterments band is affected beneath the hotlink layer. Several authors accept attempted to absorb the OSI model's layers 1 and 2 into the TCP/IP model, back these are frequently referred to in avant-garde standards (for example, by IEEE and ITU). This generally after-effects in a archetypal with 5 layers, area the hotlink band or arrangement admission band is breach into the OSI model's layers 1 and 2.

However, the IETF makes no accomplishment to chase the OSI model, although RFCs sometimes accredit to it and generally use the old OSI band numbers. The IETF has again statedcitation needed that Internet agreement and architectonics development is not advised to be OSI-compliant. RFC 3439, acclamation Internet architecture, contains a area entitled: "Layering Considered Harmful".17

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