Advantages of SS7 | disadvantages of SS7 | CCS7 | Signaling System 7
This page covers advantages and disadvantages of SS7. It mentions SS7 advantages or benefits and SS7 disadvantages or drawbacks. It also describes SS7 or CCS7 basics.
What is SS7 or CCS7?
• SS7 stands for Signaling System Number 7.
• It uses telephone signaling protocols in majority of exchanges around the world.
• It creates smart telephone network which converges normal telephone users, VOIP users and PSTN users.
• The SS7 network consists of CO or SSP, STP and SCP as shown in the figure.
• Digital signals on network exist which is independent from voice circuits.
• One signaling link serves existence of several voice circuits on the network.
• Suitable for various communication services e.g. telephony, text, data and internationally standardized.
• Supports high signaling data rates viz. 56 Kbps and 64 Kbps
Following are the useful terminologies related to SS7 network.
• SSP (Signal Switching Point) or CO (Central Office) : It functions as SS7 compliant telephone exchange which performs origination, termination and switching of calls.
• STP (Signal Transfer Point): They are packet switches of SS7 network. They perform routing functionalities. It allows exchanges to exchange signaling informations with each other.
• SCP (Signal Control Point): They are databases which take care of advanced call processing features.
• Tandem (Trunk Automatic Exchange): It allows connection between two exchanges not having direct trunk between them.
• Trunk: The link between two exchanges is known as trunk.
Benefits or advantages of SS7 | CCS7
Following are the benefits or advantages of SS7 or CCS7:
➨It enables better voice circuit utilization.
➨Signaling links are always available even during the existing calls.
➨One signaling system controls complex messages i.e. several services/features.
➨It offers high reliability compare to voice transmission.
➨It is possible to route call independent messages such as SMS, data base query, OAM (Operation and Maintenance) messages etc.
➨Expansion of services do not require replacement of old equipments with newer ones.
➨It helps in performing services which include automatic caller ID, call hold, blocking of subscriber numbers, automatic redirect, conference calls, prepaid calls, conversion of telephone numbers etc.
➨It enables high speed connection setup and transfer of data without any loss or duplication.
➨SS7 network is link between circuit switched network and IP protocol based communication network. Hence packet switched network can also be used.
➨Unlike CAS (Channel Associated Signaling), there is no interference between signaling tones by network and frequency of human speech pattern.
Drawbacks or disadvantages of SS7 | CCS7
Following are the disadvantages of SS7 or CCS7:
➨It uses more complicated switches.
➨There is no inherent testing of speech path by call setup signaling. As a result it requires explicit call continuity checks or elaborate continuity test procedures are needed.
➨It increases cost due to use of additional subnetwork.
➨The CCS7 (Common Channel Signaling System) should have very low error rate in order to function as desired.
➨CCS links can lead to single point of failure because in CCS7 single link can control thousands of voice circuits. As a result, if single link fails and no alternate routes are found, thousands of calls could be lost.
Advantages and Disadvantages of other wireless technologies
• Circuit Switching vs Packet switching • Packet Switching vs Message switching • What is an IP address • What is MAC Address • Basics of OSI and TCP-IP Layers • What is Hub • What is Switch • What is Bridge • What is Router • What is Gateway • Firewall basics • TCP-IP Packet format • ARP Protocol format