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Computer Science
Computer Catlog
Comm Network Catlog

Network Components
Network Types
The OSI Model
Protocol Notations
Physical Layer
Modulation
Transmission Media
Multiplexing
Digitization and Synchronization
Physical Layer Standards
DataLink Layer
Error Checking
Retrans - Flow Control
Sliding Window Protocol
Data Link Layer Standards
Network Layer
Switching Methods
Routing
Congestion Control
Internetworking
Network Sub layers
Transport Layer
Transport Protocol
Transport Layer Standards
Session Layer
Session Layer Role
Session Protocol
Presentation Layer
Abstract Syntax Notation
Application Layer
Common Application
Specific Application
Message Handling
LAN
IEEE 802 Standards
ANSI FDDI Standard
ISDN
Frame Relay
Broadband ISDN & ATM

The Network Layer


    The network layer handles the routing of data packets across the network, and defines the interface between a host and a network node.

Network Services


    At the outset, the network layer provides a set of services to the transport layer. These services characterize the interface between the two layers and isolate the network details (lower three layers) from the network users (upper four layers). Network service content is therefore of considerable importance.

    Network services are defined in terms of network service primitives. Summarizes the primitives together with their possible types and parameters. Please note that these primitives only serve as a modeling tool and do not imply anything about how network services are implemented.

    Addresses refer to Network Service Access Points (NSAP); these denote entities at the network layer that act as the interface to service users. Quality Of Service (QOS) denotes a set of parameters (such as error rate, delays, cost, failure likelihood, throughput) which collectively describe the quality of the network service. User data refers to actual user data provided by service users for transfer by the service provider. Options denote a variety of options that may be activated with some commands (e.g., whether data transfers can be confirmed).


Network Layer Services