Sign in Subscribe

SSCOP Service specific connection oriented protocol

Last updated on 

SSCOP, which stands for Service Specific Connection-Oriented Protocol, is a protocol that operates at the data link layer of the OSI (Open Systems Interconnection) model. It is primarily used in Asynchronous Transfer Mode (ATM) networks to provide a reliable and connection-oriented transport mechanism for user data.

SSCOP is responsible for establishing, maintaining, and terminating connections between ATM endpoints, as well as ensuring the reliable and ordered delivery of data across the connection. It achieves this by dividing data into small, fixed-sized units called protocol data units (PDUs) and encapsulating them for transmission over the ATM network.

Now, let's dive into the key features and components of SSCOP:

  1. Connection-Oriented: SSCOP establishes a logical connection between two endpoints before data transfer begins. This connection is maintained throughout the communication session and provides reliable delivery of data. It ensures that the order of data units is preserved and any lost or corrupted units are retransmitted.
  2. Segmentation and Reassembly: SSCOP breaks higher-level data into smaller PDUs for efficient transmission over the ATM network. At the receiving end, the PDUs are reassembled into the original data. This segmentation and reassembly process allows SSCOP to handle data of various sizes while maintaining the reliability and ordering guarantees.
  3. Flow Control: SSCOP incorporates flow control mechanisms to manage the rate of data transmission between the sender and receiver. This prevents overwhelming the receiver with a large volume of data. SSCOP uses a credit-based flow control scheme, where the receiver grants credits to the sender, indicating the amount of data it can accept. The sender can only send data up to the available credits.
  4. Error Control: SSCOP ensures reliable delivery of data by using error detection and correction techniques. It includes mechanisms for error detection, such as cyclic redundancy check (CRC), to verify the integrity of the PDUs. If errors are detected, the sender is notified to retransmit the affected PDUs.
  5. Connection Management: SSCOP manages the establishment, maintenance, and termination of connections between ATM endpoints. It includes procedures for connection establishment, where both endpoints negotiate connection parameters and establish synchronization. During the connection, SSCOP performs periodic maintenance functions to ensure the connection remains active. Finally, when the communication is complete, SSCOP initiates the connection termination process.
  6. Timers and Retransmission: SSCOP employs timers to handle various timeout scenarios during connection establishment, data transfer, and termination. It uses retransmission techniques to recover lost or corrupted PDUs. If an acknowledgment for a transmitted PDU is not received within a certain time period, the sender retransmits the PDU to ensure its reliable delivery.

SSCOP provides a reliable and efficient transport mechanism for user data in ATM networks. It ensures ordered delivery, error detection and correction, flow control, and connection management. By providing these features, SSCOP contributes to the overall reliability and quality of service in ATM-based communication systems.