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Unlocking the Power of SS7: Understanding the SS7 Map for Telecom

Updated: Nov 24, 2023

Table of contents:


  1. Overview of SS7

  2. Is SS7 Used in 4G?

  3. What is SS7 in telecom?

  4. What are SS7 layers?

  • Physical layer

  • Data Link Layer

  • Network Layer

  • Transport Layer

  • Session Layer

  • Presentation Layer

  • Application Layer

  1. Does GSM use SS7?

  2. Conclusion


Overview of Signalling System 7 or SS7


A set of protocols known as SS7, or Signalling System 7, is used in telecommunications networks to establish and terminate voice and data connections. It enables the phone to establish a connection with the person calling and to cut the connection after the call is over.


The 2G, 3G, and 4G mobile phone networks may be familiar. These refer to several mobile communication technology generations. In addition to being used in some 4G networks, SS7 is also used in 2G and 3G networks. There is a good probability that SS7 played a role in a phone conversation on a mobile device.


It functions at layer 3, or "control," of the OSI model (the network layer). The signaling transfer point (STP), the signaling connection control portion (SCCP), and the message transfer part (MTP) layers make up this layer's three main components. These layers cooperate to make it easier to transfer signaling messages between various areas of the network.


SS7 maps are useful for comprehending the links and linkages inside an SS7 network. These maps serve as visual representations of the network's many components and their connections. They can help determine how an SS7 network is set up and works and resolve potential problems.


Is SS7 Used in 4G?


SS7, or Signalling System 7, is a protocol used in the telecommunications industry for communication between different telephone networks. It facilitates the exchange of information between networks, such as routing calls, texting, and providing billing information.

While SS7 has been traditionally used in 2G and 3G networks, it is not commonly used in 4G networks. 4G networks use a different protocol called Diameter, specifically designed for the modern mobile communications landscape.

Therefore, network owners must prioritize network security and implement measures to safeguard their networks against intrusion. Strong security mechanisms must be implemented, and the network must be monitored and tested often to find and fix any weaknesses.

Securitygen is a cyber security firm that focuses on the telecommunications industry. Securitygen is a company that works with businesses to promote the safe and effective adoption of cutting-edge technology by recognizing the significance of a trustworthy network infrastructure. Securitygen can assist businesses in safeguarding their networks and providing value to their consumers because of their extensive knowledge of telecom cybersecurity, their wide range of products, and their global advising experience.


What is SS7 in telecom?


SS7, also known as Signalling System 7, is a standardised telecommunications protocol used by telephone service providers and carriers to exchange signalling and call control information between their networks. It is used to set up, maintain, and terminate telephone calls and exchange other types of information, such as SMS messages and data transfers.

The SS7 protocol is used by telephone service providers to route calls from one network to another, allowing users to call any phone number worldwide, regardless of location. It is also used to provide services such as call forwarding, calls waiting, and voicemail, as well as to enable advanced features such as caller ID and three-way calling.

The SS7 protocol is a critical component of the global telecommunications infrastructure and is used by nearly all telephone service providers worldwide. It is a complex and sophisticated system with many layers and protocols that work together to enable the smooth and efficient operation of the global telephone network.

Despite its importance, the SS7 protocol has also been controversial recently due to its vulnerability to security attacks and misuse. Hackers and other malicious actors have exploited weaknesses in the SS7 protocol to intercept calls and text messages and track individual users' locations. As a result, there have been efforts to improve the security of the SS7 protocol and to better protect against these types of attacks.



What are SS7 layers?

The SS7 (Signalling System 7) network is a signaling network used in telecommunications that enables the exchange of information between different communication systems. It is an essential component of modern communication systems and is used in various applications such as routing calls, text messages, and data transfer.


The SS7 network consists of several layers, each with a specific function. The main layers of the SS7 network are:


  • Physical Layer: This is responsible for the physical transmission of data between different communication systems. It consists of various hardware components such as cables, switches, and routers, which transmit data over different media, such as copper wire, fibre optic cables, and satellite.


  • Data Link Layer: This is responsible for the error-free transmission of data between different systems. It uses protocols such as HDLC (High-level Data Link Control) and LAPD (Link Access Protocol for D channel) to ensure that data is transmitted accurately and efficiently.


  • Network Layer: This is responsible for routing and delivering data between different systems. It uses protocols such as X.25 and IP (Internet Protocol) to route data through the network to its destination.


  • Transport Layer: This layer provides reliable communication between different systems. It uses protocols such as TCP (Transmission Control Protocol) and SCTP (Stream Control Transmission Protocol) to ensure that data is delivered to its destination without errors.


  • Session Layer: This is responsible for establishing, maintaining, and terminating communication between different systems. It uses protocols such as ISUP (ISDN User Part) and TUP (Telephony User Part) to establish communication between different systems.


  • Presentation Layer: This is responsible for formatting and encoding data transmitted between different systems. It uses protocols such as ASN.1 (Abstract Syntax Notation One) and XDR (External Data Representation) to encode data in a standardised format.


  • Application Layer: This is responsible for providing services to the user. It uses protocols such as MAP (Mobile Application Part) and CAP (CAMEL Application Part) to provide services such as routing calls, text messages, and data transfer.

In summary, the SS7 network is a complex and essential component of modern communication systems. It consists of several layers that work together to provide reliable and efficient communication between different systems.


Does GSM use SS7?

GSM (Global System for Mobile Communications) does use SS7 (Signalling System 7). SS7 is a signalling protocol used in telecommunications networks to facilitate the connection and disconnection of phone calls and provide additional features such as caller ID and call forwarding. It is used in both traditional landline and mobile networks, including GSM.


GSM is a digital mobile network that is widely used around the world for wireless communication. It was developed in the 1980s and has since become the most widely used mobile network technology, covering over 90% of the global market. GSM uses a variety of signalling protocols, including SS7, to facilitate communication between devices and the network.

One of the key features of SS7 in GSM is its ability to route calls between different networks and devices. This allows users to call and receive calls from other GSM networks and devices, regardless of location. SS7 also enables other features, such as call forwarding, caller ID, and voicemail, commonly used in GSM networks.

In addition to its use in GSM, SS7 is also used in other mobile technologies, such as 3G and 4G. It is a critical component of modern telecommunications networks and continues to be used in many networks around the world.


Conclusion


SS7 (Signaling System 7) is a group of telephony signaling protocols used in the PSTN to establish and terminate conversations and transport data like billing information and caller ID. Nearly every telecom company in the world adheres to this universal standard. Each layer of SS7—the Message Transfer Part (MTP), the Signaling Connection Control Part (SCCP), and the Telephone User Part—serves a different purpose (TUP). The signaling layers MTP and SCCP in SS7 are used by the Global System for Mobile Communications (GSM). However, in 4G networks, a distinct set of communication protocols known as Diameter is utilized rather than SS7. Network administrators must prioritize network security to keep their networks safe from threats.








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