"Layer 5" redirects here. For the political layer sometimes included in the OSI model, see Layer 8.
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OSI model by layer
7. Application layer
NNTP
SIP
SSI
DNS
FTP
Gopher
HTTP (HTTP/3)
NFS
NTP
SMPP
SSH
SMTP
SNMP
Telnet
DHCP
NETCONF
more....
6. Presentation layer
MIME
XDR
ASN.1
ASCII
TLS
PGP
5. Session layer
Named pipe
NetBIOS
SAP
PPTP
RTP
SOCKS
X.225[1]
4. Transport layer
TCP
UDP
SCTP
DCCP
QUIC
SPX
3. Network layer
IP
IPv4
IPv6
ICMP (ICMPv6)
IPsec
IGMP
IPX
IS-IS
AppleTalk
X.25
PLP
2. Data link layer
ATM
ARP
SDLC
HDLC
CSLIP
SLIP
GFP
PLIP
IEEE 802.2
LLC
MAC
L2TP
IEEE 802.3
Frame Relay
ITU-T G.hn DLL
PPP
X.25 LAPB
Q.922 LAPF
IEEE 802.11
1. Physical layer
RS-232
RS-449
ITU-T V-Series
I.430
I.431
PDH
SONET/SDH
PON
OTN
DSL
IEEE 802.3
IEEE 802.11
IEEE 802.15
IEEE 802.16
IEEE 1394
ITU-T G.hn PHY
USB
Bluetooth
v
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e
In the seven-layer OSI model of computer networking, the session layer is layer 5.
The session layer provides the mechanism for opening, closing and managing a session between end-user application processes, i.e., a semi-permanent dialogue. Communication sessions consist of requests and responses that occur between applications. Session-layer services are commonly used in application environments that make use of remote procedure calls (RPCs).[2]
An example of a session-layer protocol is the OSI protocol suite session-layer protocol, also known as X.225 or ISO 8327. In case of a connection loss this protocol may try to recover the connection. If a connection is not used for a long period, the session-layer protocol may close it and re-open it. It provides for either full duplex or half-duplex operation and provides synchronization points in the stream of exchanged messages.[3]
Other examples of session layer implementations include Zone Information Protocol (ZIP) – the AppleTalk[4] protocol that coordinates the name binding process, and Session Control Protocol (SCP)[5] – the DECnet Phase IV session-layer protocol.
Within the service layering semantics of the OSI network architecture, the session layer responds to service requests from the presentation layer and issues service requests to the transport layer.
^"X.225 : Information technology – Open Systems Interconnection – Connection-oriented Session protocol: Protocol specification". Archived from the original on February 1, 2021. Retrieved March 10, 2023.
^"What Is Remote Procedure Call (RPC)? Definition from SearchAppArchitecture". SearchAppArchitecture. Retrieved August 4, 2022.
^ITU-T Recommendation X.225
^"ZIP" (PDF). Apple.developer.com.
^"Session Control Protocol (SCP)". www.w3.org. Retrieved August 4, 2022.
In the seven-layer OSI model of computer networking, the sessionlayer is layer 5. The sessionlayer provides the mechanism for opening, closing and managing...
additional layers, the sessionlayer and presentation layer, as separate levels below the application layer and above the transport layer. OSI specifies...
systems are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model partitions...
application layer and issues service requests to the sessionlayer through a unique presentation service access point (PSAP). The presentation layer ensures...
In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing...
Connectionless Session protocol – ITU-T Rec. X.235 [ISO/IEC 9548-1] The sessionlayer controls the dialogues (connections) between computers. It establishes...
primary sources. The three top layers in the OSI model, i.e. the application layer, the presentation layer and the sessionlayer, are not distinguished separately...
layer of WAP with a consistent interface for two session services. The first is a connection-oriented service that operates above a transaction layer...
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers...
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with...
Network Basic Input/Output System. It provides services related to the sessionlayer of the OSI model allowing applications on separate computers to communicate...
Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications by allowing them to communicate...
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice...
layer, p. 189, explains this. Marsden 1986, Section 14.6 - The sessionlayer, p. 190, explains this. Marsden 1986, Section 14.7 - The transport layer...
In computer networking, Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs) or as part of the delivery...
FIX standard was monolithic, including application layer semantics, message encoding, and sessionlayer in a single technical specification. It remained...
the medium access control (MAC), also called media access control, is the layer that controls the hardware responsible for interaction with the wired (electrical...
Session multiplexing in a computer network is a service provided by the transport layer (see OSI Layered Model). It multiplexes several message streams...
a network service is an application running at the network application layer and above, that provides data storage, manipulation, presentation, communication...
(LLC) data communication protocol layer is the upper sublayer of the data link layer (layer 2) of the seven-layer OSI model. The LLC sublayer acts as...
address of an ISP. Deep packet inspection can be used to filter on the sessionlayer but will effectively disarm encryption protocols like TLS and SSL between...
is partitioned and isolated in a computer network at the data link layer (OSI layer 2). In this context, virtual refers to a physical object recreated...
application-SOCKS firewall with inspection feature on Layer 7 of the OSI model, the Application Layer. Because packets are inspected at 7 OSI Level the application-SOCKS...
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