A Signaling Gateway is a network component responsible for transferring signaling messages (i.e. information related to call establishment, billing, location, short messages, address conversion, and other services) between Common Channel Signaling (CCS) nodes that communicate using different protocols and transports. Transport conversion is often from SS7 to IP.
A SIGTRAN Signaling Gateway is a network component that performs packet level translation of signaling from common channel signaling (based upon SS7) to SIGTRAN signaling (based upon IP). The concept of the SIGTRAN signaling gateway was introduced in the IETF document: RFC 2719: Architectural Framework for Signaling Transport.
A signaling gateway can be implemented as an embedded component of some other network element, or can be provided as a stand-alone network element. For example: a signaling gateway is often part of a softswitch in modern VoIP deployments. The signaling gateway function can also be included within the larger operational domain of a Signal Transfer Point (STP).
Protocol conversion gateways can also convert from one network operational paradigm to another – for example, SIP to ISUP for call control , SIP to TCAP for address translation, or SIP to MAP for location or presence.
SS7
Signalling System No. 7 (SS7) is a set of telephony signaling protocols which are used to set up most of the world's public switched telephone network telephone calls. The main purpose is to set up and tear down telephone calls. Other uses include number translation, local number portability, prepaid billing mechanisms, short message service (SMS), and a variety of other mass market services.
It is usually referenced as Signalling System No. 7 or Signalling System #7, or simply abbreviated to SS7. In North America it is often referred to as CCSS7, an abbreviation for Common Channel Signalling System 7. In some European countries, specifically the United Kingdom, it is sometimes called C7 (CCITT number 7) and is also known as number 7 and CCIS7 (Common Channel Interoffice Signaling 7).
There is only one international SS7 protocol defined by ITU-T in its Q.700-series recommendations.[1] There are however, many national variants of the SS7 protocols. Most national variants are based on two widely deployed national variants as standardized by ANSI and ETSI, which are in turn based on the international protocol defined by ITU-T. Each national variant has its own unique characteristics. Some national variants with rather striking characteristics are the China (PRC) and Japan (TTC) national variants.
The Internet Engineering Task Force (IETF) has also defined level 2, 3, and 4 protocols that are compatible with SS7:
MTP2 (M2UA and M2PA)
MTP3 (M3UA)
Signalling Connection Control Part (SCCP) (SUA)
but use a Stream Control Transmission Protocol (SCTP) transport mechanism. This suite of protocols is called SIGTRAN.
The SS7 protocol stack borrows partially from the OSI Model of a packetized digital protocol stack. OSI layers 1 to 3 are provided by the Message Transfer Part (MTP) and the Signalling Connection Control Part (SCCP) of the SS7 protocol (together referred to as the Network Service Part (NSP)); for circuit related signaling, such as the Telephone User Part (TUP) or the ISDN User Part (ISUP), the User Part provides layer 7. Currently there are no protocol components that provide OSI layers 4 through 6.[1] The Transaction Capabilities Application Part (TCAP) is the primary SCCP User in the Core Network, using SCCP in connectionless mode. SCCP in connection oriented mode provides the transport layer for air interface protocols such as BSSAP and RANAP. TCAP provides transaction capabilities to its Users (TC-Users), such as the Mobile Application Part, the Intelligent Network Application Part and the CAMEL Application Part.
The Message Transfer Part (MTP) covers a portion of the functions of the OSI network layer including: network interface, information transfer, message handling and routing to the higher levels. Signalling Connection Control Part (SCCP) is at functional Level 4. Together with MTP Level 3 it is called the Network Service Part (NSP). SCCP completes the functions of the OSI network layer: end-to-end addressing and routing, connectionless messages (UDTs), and management services for users of the Network Service Part (NSP).[16] Telephone User Part (TUP) is a link-by-link signaling system used to connect calls. ISDN User Part (ISUP) is the key user part, providing a circuit-based protocol to establish, maintain, and end the connections for calls. Transaction Capabilities Application Part (TCAP) is used to create database queries and invoke advanced network functionality, or links to Intelligent Network Application Part (INAP) for intelligent networks, or Mobile Application Part (MAP) for mobile services.
Friday, November 11, 2011
Thursday, November 10, 2011
1.What is Universal Media Gateway?
The Universal Media Gateway is one of the main equipment in the Access subsystem of
the NGN. In the current implementation of the system in the country this is the main
access system that is being used since it has multiple functions. It is the most economical
solution when the telecom network is part PSTN and part NGN.
Some of the main features of the UMG
It supports interworking between different networks
It provides conversion function between different formats of traffic
Function as a Trunk gateway (TG) and as an Access gateway (AG)
Has an embedded signaling gateway (SG).
UMG8900 can be divided into two parts according to its functionality. This helps to
understand the system better.
Service switching module(SSM):
It processes the formats of various types of traffic flow. It functions as a TG connecting
the PSTN system with the NGN. This is what gives a subscriber in the NGN the chance
to call one in PSTN or any other network even though they work in different ways. In the
absence of a connection with the switch it can act as a switch in NGN. This gives it the
stand alone capability and intern more reliability.
Service switching module (SSM) consists of 4 parts
Main control frame – Management and maintenance functions of the device
and supports service access and process simultaneously.
Service frame – Process services requested by user
Central switching frame – Handles Multi-frame cascading function
Extended control frame - When the device is at maximum capacity. The
extended frame does not support access and process functions of user services,
but provides connection management and control function.
T.A.T Tilakaratne
Department of Electronic and Telecommunication Engineering
9
User access module(UAM):
This is the access point currently provided by Huawie for the users that are in the NGN.
The instrument can be at the UMG itself or function as a RSU from a distant place. It
provides integrated access function for both narrowband and broadband users.
It can even function as an AG if an IP connection is provided.
Card structure of the UMG8900
1. System Management Boards
OMU - Operation Maintenance unit
MPU - Main control unit
CMF - Connection management unit front
NET - Packet switch Net board
CLK - Clock board
CMB - Connection management unit back
PPB - Protocol processing unit
2. Signaling Gateway Board
SPF - Signaling process board
4. IP Interface Process Board
E8T - 8×FE
E1G - 1×GE
HRB – High Speed Routing Board
3. TDM Interface Process
TNU - TDM switch Net Unit
TCLU - TDM Convergence & link unit
E32 - 32×E1
S2L - 2×STM-1 optical
5. Voice Process Board
VPU - Voice Process
Unit
SRU- Signal Resource
unit
Cascading Board
FLU - Front Link Unit
BLU – Back Link Unit
UMG8900 hardware system can be divided into the following subsystems according to
their function.
1. Operation and maintenance subsystem
2. Gateway control subsystem
3. TDM access and switching subsystem
4. Packet processing subsystem
5. Service resource processing subsystem
6. Subscriber access subsystem
7. Signaling forwarding subsystem
8. Clock subsystem
9. Cascading subsystem.
1.7.1 Operation and maintenance subsystem
Control of the UMG is handled by the OMU and MPU it also does maintenance
functions. The instructions to each card originate from here. If the link to the SoftSwitch
fails internal switching is also handled from this section. The terminal access is through
here for maintenance tasks.
1.7.2 Gateway control subsystem
The messages received from the SoftSwitch that concern control of the gateway are
received through this section. The Protocol processing unit handles H.248 and MGCP
standard protocols. In a layered architecture higher level connections have to be
managed. This is achieved from the CMU which is after the PPU.
1.7.3 TDM access and switching subsystem
The access point for PSTN users is through this section. They can connect through the
S2L connection that can connect two STM 1 lines or through the E’1 interface. The voice
coming from the TDM system goes in to a switching network which is controlled by the
OMU or MPU. The signals are split in to signaling and voice.
The access of the RSU equipment that is of the MA5000 is also through the E32 card.
1.7.4 Packet processing subsystem
Picketing of data that goes in to the IP network and vise versa is done in this section. The
types of packets handled are
Voice, video, data
Signaling
Since there are no other UMG in the country only signaling going to the SoftSwitch is
going through this path. Processing of the packets, packet creation, and switching them to
their path is done from the NET Packet switch Net board under the control of the OMU.
1.7.5 Service Resource Processing Subsystem
This subsystem performs media stream format conversion and adaptation adapts
according to the user. The user can be using SS7, R2 or an internal protocol for signaling.
The system has to adapt accordingly and send the replies in the same format.
Format conversion is required since systems work in different ways. They have to be
brought to a common format and also the reverse conversion has to be done.
Main functions handled are
1) Voice transcoding
2) Echo cancellation
3) Announcement play
4) Digit collection
5) Multi-party conference
Voice transcoding is done to reduce the amount of data transfer in the IP side. It also
helps in error handling. VPU is responsible for voice transcoding.
There are many transcoding methods that can be used a chart is given in the Appendix.
SRU is engaged in announcement playing, DTMF generation and detection, digit
collection, audio mixing (conference) and FSK. It handles the Register Signaling part of
R2 signaling. The DTMF generation and digit collection is done in handling R2.
1.7.8 Signaling forwarding subsystem
This subsystem includes some of the components that were included in other subsystems
but also work in signal processing.
According to the present implementation three kinds of signaling enter the UMG from
the E32 interface
R2
SS7
V5.2 (an internal protocol used for signaling with the MA5000)
R2
The Line signaling is directly received from the CMU and sent to the PPU. Register
signaling after being recognized at the TNU is sent to the SRU. The information collected
is sent in a data packet form to the CMU and then to the PPU. Here the signals are
converted in to H.248 and sent to the SoftSwitch. The return path is also the same.
SS7 & V5.2
The signaling is separated at the TNU and forwarded to the SPF. Protocol conversion
from SS7 to Sigtran occurs here. After that the Sigtran messages are sent along the IP
network to the soft switch. The replies come through the same path and commands to the
UMG come through the PPU.
1.7.9 Clock subsystem
Provides the clock signal to the system. For accuracy this can be taken from a satellite.
1.7.10 Cascading subsystem
This connects the central switching frame with the other frames. The connection
management is its main function.
Subscriber Access paths to the UMG
The UMG provides the subscribers with a diversity of service access. The UAM handles
the access of directly connected subscribers. There are two methods of connection.
The unit can be on site and connected by a network cable through the network
It can be at a remote location and connected using a number of E’1 links
depending on the traffic.
T.A.
1.7.11 The UA5000 which is the distant unit does not have a stand alone function.
Figure 7-3: UA5000
PWX- Power
TSS – Test (operates the test relay)
PV8 – Transmission control card
This supports 8 E’1 each with the UMG. The time slots for communication and the V5.2
protocol are handled from this card.
RSP – Bus network control card
A32 – sub card that handle 32 subscribers.
ASL – Coin box connection card has line reversal and meter pulsing capability.
DSL – ISDN connection card
APMA – Broad band service connection card
ADMA – Subscriber interface card for broadband.
An IP network connection is needed to give the broadband service. Then it will be
directly controlled by the SoftSwitch without going through the UMG. The second frame
is an expansion frame which connects with the PV8 using the RSP. From the 31 time
slots in the E’1, one is used to send control messages using the V5.2 protocol. The
identity of the subscriber that is initiating a call, ring signal from the UMG to the
UA5000 and also the commands to the test card are sent through this.
the NGN. In the current implementation of the system in the country this is the main
access system that is being used since it has multiple functions. It is the most economical
solution when the telecom network is part PSTN and part NGN.
Some of the main features of the UMG
It supports interworking between different networks
It provides conversion function between different formats of traffic
Function as a Trunk gateway (TG) and as an Access gateway (AG)
Has an embedded signaling gateway (SG).
UMG8900 can be divided into two parts according to its functionality. This helps to
understand the system better.
Service switching module(SSM):
It processes the formats of various types of traffic flow. It functions as a TG connecting
the PSTN system with the NGN. This is what gives a subscriber in the NGN the chance
to call one in PSTN or any other network even though they work in different ways. In the
absence of a connection with the switch it can act as a switch in NGN. This gives it the
stand alone capability and intern more reliability.
Service switching module (SSM) consists of 4 parts
Main control frame – Management and maintenance functions of the device
and supports service access and process simultaneously.
Service frame – Process services requested by user
Central switching frame – Handles Multi-frame cascading function
Extended control frame - When the device is at maximum capacity. The
extended frame does not support access and process functions of user services,
but provides connection management and control function.
T.A.T Tilakaratne
Department of Electronic and Telecommunication Engineering
9
User access module(UAM):
This is the access point currently provided by Huawie for the users that are in the NGN.
The instrument can be at the UMG itself or function as a RSU from a distant place. It
provides integrated access function for both narrowband and broadband users.
It can even function as an AG if an IP connection is provided.
Card structure of the UMG8900
1. System Management Boards
OMU - Operation Maintenance unit
MPU - Main control unit
CMF - Connection management unit front
NET - Packet switch Net board
CLK - Clock board
CMB - Connection management unit back
PPB - Protocol processing unit
2. Signaling Gateway Board
SPF - Signaling process board
4. IP Interface Process Board
E8T - 8×FE
E1G - 1×GE
HRB – High Speed Routing Board
3. TDM Interface Process
TNU - TDM switch Net Unit
TCLU - TDM Convergence & link unit
E32 - 32×E1
S2L - 2×STM-1 optical
5. Voice Process Board
VPU - Voice Process
Unit
SRU- Signal Resource
unit
Cascading Board
FLU - Front Link Unit
BLU – Back Link Unit
UMG8900 hardware system can be divided into the following subsystems according to
their function.
1. Operation and maintenance subsystem
2. Gateway control subsystem
3. TDM access and switching subsystem
4. Packet processing subsystem
5. Service resource processing subsystem
6. Subscriber access subsystem
7. Signaling forwarding subsystem
8. Clock subsystem
9. Cascading subsystem.
1.7.1 Operation and maintenance subsystem
Control of the UMG is handled by the OMU and MPU it also does maintenance
functions. The instructions to each card originate from here. If the link to the SoftSwitch
fails internal switching is also handled from this section. The terminal access is through
here for maintenance tasks.
1.7.2 Gateway control subsystem
The messages received from the SoftSwitch that concern control of the gateway are
received through this section. The Protocol processing unit handles H.248 and MGCP
standard protocols. In a layered architecture higher level connections have to be
managed. This is achieved from the CMU which is after the PPU.
1.7.3 TDM access and switching subsystem
The access point for PSTN users is through this section. They can connect through the
S2L connection that can connect two STM 1 lines or through the E’1 interface. The voice
coming from the TDM system goes in to a switching network which is controlled by the
OMU or MPU. The signals are split in to signaling and voice.
The access of the RSU equipment that is of the MA5000 is also through the E32 card.
1.7.4 Packet processing subsystem
Picketing of data that goes in to the IP network and vise versa is done in this section. The
types of packets handled are
Voice, video, data
Signaling
Since there are no other UMG in the country only signaling going to the SoftSwitch is
going through this path. Processing of the packets, packet creation, and switching them to
their path is done from the NET Packet switch Net board under the control of the OMU.
1.7.5 Service Resource Processing Subsystem
This subsystem performs media stream format conversion and adaptation adapts
according to the user. The user can be using SS7, R2 or an internal protocol for signaling.
The system has to adapt accordingly and send the replies in the same format.
Format conversion is required since systems work in different ways. They have to be
brought to a common format and also the reverse conversion has to be done.
Main functions handled are
1) Voice transcoding
2) Echo cancellation
3) Announcement play
4) Digit collection
5) Multi-party conference
Voice transcoding is done to reduce the amount of data transfer in the IP side. It also
helps in error handling. VPU is responsible for voice transcoding.
There are many transcoding methods that can be used a chart is given in the Appendix.
SRU is engaged in announcement playing, DTMF generation and detection, digit
collection, audio mixing (conference) and FSK. It handles the Register Signaling part of
R2 signaling. The DTMF generation and digit collection is done in handling R2.
1.7.8 Signaling forwarding subsystem
This subsystem includes some of the components that were included in other subsystems
but also work in signal processing.
According to the present implementation three kinds of signaling enter the UMG from
the E32 interface
R2
SS7
V5.2 (an internal protocol used for signaling with the MA5000)
R2
The Line signaling is directly received from the CMU and sent to the PPU. Register
signaling after being recognized at the TNU is sent to the SRU. The information collected
is sent in a data packet form to the CMU and then to the PPU. Here the signals are
converted in to H.248 and sent to the SoftSwitch. The return path is also the same.
SS7 & V5.2
The signaling is separated at the TNU and forwarded to the SPF. Protocol conversion
from SS7 to Sigtran occurs here. After that the Sigtran messages are sent along the IP
network to the soft switch. The replies come through the same path and commands to the
UMG come through the PPU.
1.7.9 Clock subsystem
Provides the clock signal to the system. For accuracy this can be taken from a satellite.
1.7.10 Cascading subsystem
This connects the central switching frame with the other frames. The connection
management is its main function.
Subscriber Access paths to the UMG
The UMG provides the subscribers with a diversity of service access. The UAM handles
the access of directly connected subscribers. There are two methods of connection.
The unit can be on site and connected by a network cable through the network
It can be at a remote location and connected using a number of E’1 links
depending on the traffic.
T.A.
1.7.11 The UA5000 which is the distant unit does not have a stand alone function.
Figure 7-3: UA5000
PWX- Power
TSS – Test (operates the test relay)
PV8 – Transmission control card
This supports 8 E’1 each with the UMG. The time slots for communication and the V5.2
protocol are handled from this card.
RSP – Bus network control card
A32 – sub card that handle 32 subscribers.
ASL – Coin box connection card has line reversal and meter pulsing capability.
DSL – ISDN connection card
APMA – Broad band service connection card
ADMA – Subscriber interface card for broadband.
An IP network connection is needed to give the broadband service. Then it will be
directly controlled by the SoftSwitch without going through the UMG. The second frame
is an expansion frame which connects with the PV8 using the RSP. From the 31 time
slots in the E’1, one is used to send control messages using the V5.2 protocol. The
identity of the subscriber that is initiating a call, ring signal from the UMG to the
UA5000 and also the commands to the test card are sent through this.
Friday, May 28, 2010
6.What is softxswitch?
Introducing the VoIP Softswitch
Many companies looking to upgrade their phone systems may not be aware of the benefits a VoIP softswitch can offer. What is a VoIP softswitch? The biggest difference between traditional phone systems and a VoIP softswitch lies in hardware vs. software. A VoIP softswitch is a software-driven phone system.
In the past, phone systems used physical switchboards to route calls; the VoIP softswitch offers a different delivery method. With a VoIP softswitch, software is used to control connections at the point where circuit networks and packet networks meet.
Today, a single device—coupled with VoIP softswitch software—can be used to handle both switching logic and switching fabric. These two VoIP softswitch components can be broken down as follows: a call agent to perform billing, routing and signaling functions and a media gateway to connect digital media streams (voice and data) into a single path.
For businesses, there are a number of advantages to using a VoIP softswitch. Perhaps the biggest advantage of a VoIP softswitch is cost. Being able to route calls over IP networks is cheaper than traditional telephony, and a VoIP softswitch, being software-based, is less expensive to buy and maintain.
Another advantage of a VoIP softswitch is ease of use and administration. A VoIP softswitch greatly simplifies administrative tasks associated with managing a phone system. In fact, most VoIP softswitches are so easy to maintain that IT staff can perform administration. The admin simplicity of a VoIP softswitch saves a company money it would otherwise have to spend on telephony experts.
For users, too, a VoIP softswitch offers advantages. Employees using a VoIP softswitch may be able to perform basic administrative tasks (like changing voicemail forwarding options) on their own, using a browser-based interface. A VoIP softswitch also may offers users the ability to remotely access the office phone system when traveling or working in the field.
Clearly, introduction of the VoIP softswitch is a positive event for businesses. If your company hasn’t considered picking a VoIP softswitch yet, now might be the time to do so!
Many companies looking to upgrade their phone systems may not be aware of the benefits a VoIP softswitch can offer. What is a VoIP softswitch? The biggest difference between traditional phone systems and a VoIP softswitch lies in hardware vs. software. A VoIP softswitch is a software-driven phone system.
In the past, phone systems used physical switchboards to route calls; the VoIP softswitch offers a different delivery method. With a VoIP softswitch, software is used to control connections at the point where circuit networks and packet networks meet.
Today, a single device—coupled with VoIP softswitch software—can be used to handle both switching logic and switching fabric. These two VoIP softswitch components can be broken down as follows: a call agent to perform billing, routing and signaling functions and a media gateway to connect digital media streams (voice and data) into a single path.
For businesses, there are a number of advantages to using a VoIP softswitch. Perhaps the biggest advantage of a VoIP softswitch is cost. Being able to route calls over IP networks is cheaper than traditional telephony, and a VoIP softswitch, being software-based, is less expensive to buy and maintain.
Another advantage of a VoIP softswitch is ease of use and administration. A VoIP softswitch greatly simplifies administrative tasks associated with managing a phone system. In fact, most VoIP softswitches are so easy to maintain that IT staff can perform administration. The admin simplicity of a VoIP softswitch saves a company money it would otherwise have to spend on telephony experts.
For users, too, a VoIP softswitch offers advantages. Employees using a VoIP softswitch may be able to perform basic administrative tasks (like changing voicemail forwarding options) on their own, using a browser-based interface. A VoIP softswitch also may offers users the ability to remotely access the office phone system when traveling or working in the field.
Clearly, introduction of the VoIP softswitch is a positive event for businesses. If your company hasn’t considered picking a VoIP softswitch yet, now might be the time to do so!
5.What is softxwitch?
Softswitch (software switch) is a generic term for any open application program interface (API) software used to bridge a public switched telephone network (PSTN) and Voice over Internet Protocol (VoIP) by separating the call control functions of a phone call from the media gateway (transport layer).
As service providers move toward offering voice, video and data services on single packet-based networks, they will come to rely on softswitches to handle voice calls.
These server-based devices manage phone calls as they come in from packet access links and clear a path for them across the packet network to the destination phones.
But because most phones are still connected via the traditional public phone network, these softswitches also must be able to complete calls across circuit-switched networks. To do that, they control other network elements including media gateways and signaling gateways. Because of this function, softswitches are also referred to as media gateway controllers.
A media gateway translates traffic from, for instance, an ATM access link, to time-division multiplexer or IP that is used as the backbone of the carrier network. A signaling gateway mediates between the signaling used by access devices and signaling used across the service provider network. With a traditional phone network, this is called Signaling System 7.
The definition of softswitches varies. The International Softswitch Consortium limits the term softswitch to the media gateway controller. Some vendors include the media gateway or signaling gateway, too, as part of the softswitch itself.
To set up phone services, softswitches must tap into databases and application servers that define the services customers get. Because they do this via standard API, vendors other than the ones that make the softswitches can write the service programs.
Softswitch proponents tout this as an advantage because it means more providers can write these programs, encouraging competition that will reduce cost and promote innovation. Traditional circuit-switched voice switches include all the functions of a softswitch plus the service applications and databases, much of which is based on proprietary software. So service providers are locked in to one vendor.
Softswitches are also less expensive than traditional voice switches and let service providers migrate away from maintaining a separate network just for voice.
As service providers move toward offering voice, video and data services on single packet-based networks, they will come to rely on softswitches to handle voice calls.
These server-based devices manage phone calls as they come in from packet access links and clear a path for them across the packet network to the destination phones.
But because most phones are still connected via the traditional public phone network, these softswitches also must be able to complete calls across circuit-switched networks. To do that, they control other network elements including media gateways and signaling gateways. Because of this function, softswitches are also referred to as media gateway controllers.
A media gateway translates traffic from, for instance, an ATM access link, to time-division multiplexer or IP that is used as the backbone of the carrier network. A signaling gateway mediates between the signaling used by access devices and signaling used across the service provider network. With a traditional phone network, this is called Signaling System 7.
The definition of softswitches varies. The International Softswitch Consortium limits the term softswitch to the media gateway controller. Some vendors include the media gateway or signaling gateway, too, as part of the softswitch itself.
To set up phone services, softswitches must tap into databases and application servers that define the services customers get. Because they do this via standard API, vendors other than the ones that make the softswitches can write the service programs.
Softswitch proponents tout this as an advantage because it means more providers can write these programs, encouraging competition that will reduce cost and promote innovation. Traditional circuit-switched voice switches include all the functions of a softswitch plus the service applications and databases, much of which is based on proprietary software. So service providers are locked in to one vendor.
Softswitches are also less expensive than traditional voice switches and let service providers migrate away from maintaining a separate network just for voice.
4.What is softswitch?
• The advantages of the Softswitch vs. the traditional circuit switch are:
• New services and revenue stream for service providers
• Flexibility in deployment and operation
• Unified messaging
• Easy integration of dissimilar networks and components
• Lower cost of solution deployment and total ownership
Softswitch technology enables connectivity between the Internet, wireless networks, cable networks and traditional wireline telephony network, which results a converged network.
Related Terms: Packet Switching, Network Switch, PSTN, Class 5 Switch, Class 4 Switch, Call Agent, Media Gateway Controller
3.What is softswitch?
A softswitch is a central device in a telecommunications network which connects telephone calls from one phone line to another, entirely by means of software running on a computer system. This work was formerly carried out by hardware, with physical switchboards to route the calls.
A softswitch is typically used to control connections at the junction point between circuit and packet networks. A single device containing both the switching logic and the switching fabric can be used for this purpose; however, modern technology has led to a preference for decomposing this device into a Call Agent and a Media Gateway.
The Call Agent takes care of functions including billing, call routing, signalling, call services and so on and is the 'brains' of the outfit. A Call Agent may control several different Media Gateways in geographically dispersed areas over a TCP/IP link.
The Media Gateway connects different types of digital media stream together to create an end-to-end path for the media (voice and data) in the call. It may have interfaces to connect to traditional PSTN networks like DS1 or DS3 ports (E1 or STM1 in the case of non-US networks), it may have interfaces to connect to ATM and IP networks and in the modern system will have Ethernet interfaces to connect VoIP calls. The call agent will instruct the media gateway to connect media streams between these interfaces to connect the call - all transparently to the end-users.
The softswitch generally resides in a building owned by the telephone company called a central office. The central office will have telephone trunks to carry calls to other offices owned by the telecommunication company and to other telecommunication companies (aka the Public Switched Telephone Network or PSTN).
Looking towards the end users from the switch, the Media Gateway may be connected to several access devices. These access devices can range from small Analog Telephone Adaptors (ATA) which provide just one RJ11 telephone jack to an Integrated Access Device (IAD) or PBX which may provide several hundred telephone connections.
Typically the larger access devices will be located in a building owned by the telecommunication company near to the customers they serve. Each end user can be connected to the IAD by a simple pair of copper wires.
The medium sized devices and PBXs will typically be used in a business premises and the single line devices would probably be found in residential premises.
At the turn of the 21st century with IP Multimedia Subsystem or IMS), the Softswitch element is represented by the Media Gateway Controller (MGC) element, and the term "Softswitch" is rarely used in the IMS context, rather it is called AGCF (Access Gateway Control Function).
A softswitch is typically used to control connections at the junction point between circuit and packet networks. A single device containing both the switching logic and the switching fabric can be used for this purpose; however, modern technology has led to a preference for decomposing this device into a Call Agent and a Media Gateway.
The Call Agent takes care of functions including billing, call routing, signalling, call services and so on and is the 'brains' of the outfit. A Call Agent may control several different Media Gateways in geographically dispersed areas over a TCP/IP link.
The Media Gateway connects different types of digital media stream together to create an end-to-end path for the media (voice and data) in the call. It may have interfaces to connect to traditional PSTN networks like DS1 or DS3 ports (E1 or STM1 in the case of non-US networks), it may have interfaces to connect to ATM and IP networks and in the modern system will have Ethernet interfaces to connect VoIP calls. The call agent will instruct the media gateway to connect media streams between these interfaces to connect the call - all transparently to the end-users.
The softswitch generally resides in a building owned by the telephone company called a central office. The central office will have telephone trunks to carry calls to other offices owned by the telecommunication company and to other telecommunication companies (aka the Public Switched Telephone Network or PSTN).
Looking towards the end users from the switch, the Media Gateway may be connected to several access devices. These access devices can range from small Analog Telephone Adaptors (ATA) which provide just one RJ11 telephone jack to an Integrated Access Device (IAD) or PBX which may provide several hundred telephone connections.
Typically the larger access devices will be located in a building owned by the telecommunication company near to the customers they serve. Each end user can be connected to the IAD by a simple pair of copper wires.
The medium sized devices and PBXs will typically be used in a business premises and the single line devices would probably be found in residential premises.
At the turn of the 21st century with IP Multimedia Subsystem or IMS), the Softswitch element is represented by the Media Gateway Controller (MGC) element, and the term "Softswitch" is rarely used in the IMS context, rather it is called AGCF (Access Gateway Control Function).
2.What is softxswitch?
A softswitch is an API that is used to bridge a traditional PSTN and VoIP by linking PSTN to IP networks and managing traffic that contains a mixture of voice, fax, data and video. Softswitches are able to process the signaling for all types of packet protocols. Softswitch is a software
-based switching platform, which is opposed to traditional hardware-based switching center technology. Softswitches also are based on open systems, another difference between them and traditional proprietary hardware switching systems.
Softswitch is also called media gateway controller, call agent and gatekeeper.
-based switching platform, which is opposed to traditional hardware-based switching center technology. Softswitches also are based on open systems, another difference between them and traditional proprietary hardware switching systems.
Softswitch is also called media gateway controller, call agent and gatekeeper.
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