OSI model: Difference between revisions

Revision as of 09:59, 23 July 2014

Revision as of 10:01, 24 July 2014

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[[Security service (telecommunication)|Security services]] are not related to a specific layer: they can be related by several layers, as defined by [[ITU-T]] X.800 Recommendation.<ref name="x800"/>

These services are aimed to improve the en [[network design]] and [[network management]] protocols. Appropriate choices for both of these are needed to protect against [[denial of service]].{{cit[[Information Security|CIA triad]] ([[confidentiality]], [[integrity]], and [[availability]]) of transmitted data. In practice, the availability of communication service is determined by the interaction betweenbetweation [[network===Layer design]]1: andphysical [[network management]] protocols. Appropriate choices for both of these are needed to protect against [[denial of service]].{{citation needed|datelayer===April 2013}}

===Layer 1: physical layer===

The [[physical layer]] has the following major functions:

* it defines the [[electrical]] and physical specifications of the data connection. It defines the relationship between a device and a physical [[transmission medium]] (e.g., a copper or [[optical fiber cable|fiber optical cable]]). This includes the layout of [[Lead (electronics)|pins]], [[voltage]]s, line [[Characteristic impedance|impedance]], [[cable]] [[specification]]s, signal timing, [[network hub|hub]]s, [[repeater]]s, [[network card|network adapter]]s, [[host adapter|host bus adapter]]s (HBA used in [[storage area network]]s) and more.