Two distinct techniques are used in data communications to transfer data. Each has its own advantages and disadvantages. They are the connection-oriented method and the connectionless method:
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In general, transport protocols can be characterized as being either connection-oriented or connectionless. Connection-oriented services must first establish a connection with the desired service before passing any data. A connectionless service can send the data without any need to establish a connection first. In general, connection-oriented services provide some level of delivery guarantee, whereas connectionless services do not. Connection-oriented service involves three phases: connection establishment, data transfer, and connection termination. During connection establishment, the end nodes may reserve resources for the connection. The end nodes also may negotiate and establish certain criteria for the transfer, such as a window size used in TCP connections. This resource reservation is one of the things exploited in some denial of service (DOS) attacks. An attacking system will send many requests for establishing a connection but then will never complete the connection. The attacked computer is then left with resources allocated for many never-completed connections. Then, when an end node tries to complete an actual connection, there are not enough resources for the valid connection. The data transfer phase occurs when the actual data is transmitted over the connection. During data transfer, most connection-oriented services will monitor for lost packets and handle resending them. The protocol is generally also responsible for putting the packets in the right sequence before passing the data up the protocol stack. When the transfer of data is complete, the end nodes terminate the connection and release resources reserved for the connection. Connection-oriented network services have more overhead than connectionless ones. Connection-oriented services must negotiate a connection, transfer data, and tear down the connection, whereas a connectionless transfer can simply send the data without the added overhead of creating and tearing down a connection. Each has its place in internetworks.
Connection-oriented service requires as session connection be established before any data can be sent with a direct physical connection between the sessions. This often considered to be a more reliable network service than the alternative, connectionless service. Fore more information you can visit website:http://www.iyogibusiness.com
-Unacknowledged connectionless service consists of having the source machine send independent frames to the destination machine without having the destination machine acknowledged. Most LAN's use this service. -Acknowledged connectionless service in this service there are no logical connections used but each frame sent individually acknowledged. In this way the sender knows whether a frame has arrived correctly. It is useful on wireless systems.
Unacknowledged connectionless service
Connectionless Service In a connectionless service, the packets are sent from one party to another with no need for connection establishment or connection release. The packets are not numbered; they may be delayed, lost, or arrive out of sequence. Connection-Oriented Services In a connection-oriented service, a connection is first established between the sender and the receiver. Data are transferred. At the end, the connection is released. Connection Establishment Connection establishment involves the following: Host A sends a packet to announce its wish for connection and includes its initialization information about traffic from A to B. Host B sends a packet to acknowledge (confirm) the request of A. Host B sends a packet that includes its initialization information about traffic from B to A. Host A sends a packet to acknowledge (confirm) the request of B. This connection establishment implies the steps i.e. bind, connect, listen & accept
Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing Where is the following items located in IVP4 header? Congestion Control Differentiated Services/QOS (Quality of Service) Error detection and correction Flow Control "Connection oriented" Queues/Queuing
They allow stations to reserve resources during the establishment of connections
They allow stations to reserve resources during the establishment of connections
The Logical Link Control specifies the following mechanisms1. for addressing stations across the medium2. for controlling the exchange of data between two users.There are three types of services provided by the Logical Link Layer. They are1. Connection mode service - A logical connection is set up between two users.2. Acknowledged connectionless service- No connections are involved. But data grams are acknowledged.3. Unacknowledged connectionless service- Operates in datagram style. No guarantee for the delivery of data. The service does not include flow control or error control mechanisms.
application presentation session **transport network The transport layer of the osi model
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