Sign in Subscribe

CCS (Common Channel Signaling)

Last updated on 

Introduction

Common Channel Signaling (CCS) is a telecommunication signaling technology that allows for the exchange of call control and signaling messages between different network elements, such as switches, routers, and signaling gateways, over a dedicated signaling channel that is separate from the voice or data channel used to carry the actual conversation. This enables faster and more efficient communication between network elements, as well as the ability to support advanced features such as call forwarding, call waiting, and caller ID. This article will provide a detailed explanation of CCS, its architecture, protocols, and implementation.

CCS Architecture

CCS is typically implemented using a hierarchical architecture that consists of three levels: the signaling gateway level, the signaling transfer point (STP) level, and the signaling end point (SEP) level.

At the highest level, the signaling gateway is responsible for converting signaling messages between different signaling protocols, such as SS7 (Signaling System No. 7) and ISDN (Integrated Services Digital Network). It also serves as a gateway between the signaling network and other networks, such as the Internet or a wireless network.

The STP level is responsible for routing signaling messages between different signaling endpoints. It acts as a network switch that connects signaling endpoints to each other and ensures that signaling messages are delivered to their intended destination.

The lowest level, the SEP level, is responsible for providing signaling services to the actual network elements, such as switches and routers. It handles the signaling messages that are exchanged between network elements to control call setup, teardown, and other call-related features.

CCS Protocols

CCS uses a number of different protocols to facilitate the exchange of signaling messages between network elements. These protocols include:

  1. Signaling System No. 7 (SS7): SS7 is a protocol suite that is widely used in CCS networks. It provides a range of signaling functions, such as call setup, teardown, and routing, as well as support for advanced features like caller ID and call waiting.
  2. Integrated Services Digital Network User Part (ISUP): ISUP is a protocol used to set up and tear down voice calls over the PSTN (Public Switched Telephone Network). It provides call control functions such as call setup, teardown, and circuit allocation.
  3. Transaction Capabilities Application Part (TCAP): TCAP is a protocol used to provide advanced signaling services, such as database queries and updates, over the signaling network.
  4. Message Transfer Part (MTP): MTP is a protocol used to provide reliable transport of signaling messages between signaling endpoints. It ensures that signaling messages are delivered to their intended destination and that they are delivered in the correct order.

CCS Implementation

CCS can be implemented in a variety of ways, depending on the network topology, the signaling protocols in use, and the types of network elements that are being connected. Some common implementation scenarios include:

  1. Signaling Gateway: A signaling gateway is a standalone device that connects two or more networks and provides protocol conversion between different signaling protocols. For example, a signaling gateway might convert SS7 signaling messages to ISDN signaling messages.
  2. STP: An STP is a network switch that routes signaling messages between signaling endpoints. It provides a central point for signaling message routing and enables the efficient exchange of signaling messages across a wide area network (WAN).
  3. SEP: A SEP is a network element, such as a switch or a router, that provides signaling services to other network elements. It handles signaling messages that are exchanged between network elements to control call setup, teardown, and other call-related features.

CCS Benefits

CCS provides a number of benefits for telecommunication networks, including:

  1. Faster Call Setup: CCS enables faster call setup times by providing a dedicated signaling channel that is separate from the voice or data channel used to carry the actual conversation. This allows signaling messages to be exchanged more quickly and efficiently, reducing call setup times.
  2. Advanced Features: CCS enables advanced call features, such as call waiting, call forwarding, and caller ID, which are not possible with traditional signaling methods.
  3. Improved Network Management: CCS provides better network management capabilities, such as centralized routing and control, which can lead to improved network reliability and availability.
  4. Scalability: CCS is highly scalable, which makes it suitable for use in large telecommunication networks. It can support a large number of signaling endpoints and can handle a high volume of signaling traffic.
  5. Cost-Effective: CCS is a cost-effective signaling solution, as it eliminates the need for multiple signaling links between network elements, reducing the overall cost of the signaling network.

CCS Challenges

CCS also poses some challenges for telecommunication networks, including:

  1. Complexity: CCS is a complex signaling technology that requires specialized equipment and protocols to be implemented. This complexity can make it difficult to troubleshoot and maintain the signaling network.
  2. Security: CCS networks are vulnerable to security threats, such as hacking and unauthorized access, which can compromise the integrity of the signaling network.
  3. Interoperability: CCS networks must be able to interoperate with other signaling networks and protocols, which can be challenging due to differences in signaling standards and protocols.
  4. Reliability: CCS networks must be highly reliable, as any failure or downtime can result in a loss of service for end-users.

Conclusion

Common Channel Signaling (CCS) is a telecommunication signaling technology that provides a dedicated signaling channel for the exchange of call control and signaling messages between different network elements. CCS offers a number of benefits, including faster call setup, advanced features, improved network management, scalability, and cost-effectiveness. However, it also poses some challenges, such as complexity, security, interoperability, and reliability. Despite these challenges, CCS remains an important technology for telecommunication networks and is widely used in modern communication systems.