What is Out-of-Band Signaling?

What is Out-of-Band Signaling? : This question has been asked many times by friends, so this article has been written about signaling. This article will specifically explain what is Out-of-Band Signaling and why is Out-of-Band Signaling. We will first try to learn about signaling. To get complete information, all of you have to read the entire article, information cannot be obtained by just looking at the subject.

Very special topics will be discussed in this article like- What is Signaling?, What is Out-of-Band Signaling? , Why Out-of-Band Signaling? etc. If you want any kind of information related to the telecom sector, then comment me, your problem will be solved as soon as possible. If you all liked this article "What is Out-of-Band Signaling?" then reach out to others and encourage me by commenting. Now I am going to explain what is signaling?

What is Signaling?

In simple word we can say that signaling refers to the exchange of information between call components necessary to provide and maintain service. Users of the public switched telephone networks, We exchange signaling with network elements all the time. We can take an examples of signaling between a telephone subscriber and the telephone network include: dialing digits, providing a dial tone, accessing a voice mailbox, sending a call-waiting tone, dialing * 66 (to retrieve a busy number), etc.

Signaling system 7 (SS7) is a means by which information is exchanged across telephone networks. Information is expressed in the form of a message. Signaling system 7 messages can provide such information:

I am sending you a call from 212-555-1234 to 718-555-5678 (or any other number according to your country). For this look at trunk 067. Someone just dialed 800-555-1212. Where do I route the call? The customer called for a call on trunk 11 is busy. Continue the call and open a busy tone. The route to XXX is congested. Please do not send any messages to XXX unless they are Priority 2 or higher. Presently I am taking another trunk 143 out of service for maintenance. The special feature of SS7 is provide the high-speed packet data, and out-of-band signaling.

What is Out-of-Band Signaling?

Out-of-band signaling is signaling that does not occur on the same path of conversation. We think of signaling as in-band. We hear dial tones, dial numerals, and hear the same channel strings ringing on the same channel. When the call is complete, we talk on the same path that was used for signaling. Traditional telephony also worked in this way.

The indications for setting a call between one switch and another are always on the same trunk that will eventually take the call. Signaling took the form of a series of multi-frequency (MF) tones, similar to touch tone dialing between switches.

Out-of-band signaling is characterized that it create a separate digital channel for the exchange of signal information. This established  channel is called a signaling link. This established new signaling links are used to carry all necessary signaling messages between nodes. Thus, when a call is placed, the dialed digits, trunk selected, and other relevant information are sent between switches using their signaling links, rather than trunks that will eventually carry the conversation. Today, signaling links carry information at a rate of 56 or 64 kilobytes per second (kbps).

It is keep in mind that with interest- SS7 only between network elements, means we can say that  SS7 is used only for signaling between network elements, ISDN extends the concept of out-of-band signaling from the interface between the D channel subscriber and the switch. With ISDN service, signaling that must be communicated between the user station and the local switch is performed on a separate digital channel called the D channel. Voice or data that includes a call is performed on one or more B channels.

Why Out-of-Band Signaling?

Out-of-band signaling has several advantages that make it more desirable than traditional in-band signaling: it allows the transport of more data at high speeds (taking data much faster than 56 kbps MF out-pulsing). This allows signaling at any time throughout the entire duration of the call, not just at the beginning. This enables it to deliver signals to network elements that have no direct trunk connection.

Last Word

Dear friends, I have tried to provide you complete information in short words, yet if you want more information about any point, then comment me so that I can explain those points in more detail. Out-of-band signaling is not a small subject but I have tried to be worded in less than. How did you all like this article- What is Out-of-Band Signaling?, comment me and share it with others as well.