modul 2 softswitch

5/27/2018 Modul 2 Softswitch

1/68

3

Softswitch


2/68

Softswitch

ArchitectureInternational Softswitch

Consortium (ISC) Reference


3/68

SoftswitchDefining andRelationship toNGN

Source: Study on Application of Softswitch in Wireless Networkpage 128


4/68

Functional Plane

ISC Reference Softswitch Architecture

Application/Feature Server(SCP, Service Logic, LDAP Server)

Service & Application Plane

Transport Plane

ManagementPlane

Call Agent, MGC, Softswitch, GK

IP Transport Domain:IP Backbone, Routers, Switches, BGsQoS Mechanism (RSVP, Diffserve,MPLS...), MS (Bearer Portion)

InterworkingDomain:TG (MG), SG,InterworkingGateway

Non-IP Access Domain:Wireline Access (AG, Access Proxies)Mobile Access (RAN AG)Broadband Access (IADs, MTAs)

MediaServer

IN/AIN

Inter-NetworkSwitch

PSTN/SS7/ATMNetworks

other VoIPNetworks

Non-IP Terminals/Mobile NetworksIP Phones (H.323, SIP,

MGCP, ...),IP Terminals,IP PBX

Subscriber &ServiceProvisioning,NetworkManagement,OperationSupport, BillingSupport

Open APIs & Protocols (JAIN, Parlay, XML, SIP)

Signaling (MGCP, H.248, SIP)ApplicationS

ignaling(SIP)

SIP-T; H.323Call Control & Signaling Plane


5/68

1. Transport Plane Responsible transport of messages(call signaling, call and media

setup, or media)across the VoIP network. Transport mechanism(s) for these messages based on any technology that

satisfies the requirements for carrying these types of traffic.

Provides access for signaling and media with externalnetworks, or terminals to VoIP networks.

Transport Plane devices and functions are controlled by Call Control &Signaling Plane.

The transport plane is further divided into three domains: IP Transport Domain : Interworking Domain; Non-IP Access Domain

a. IP Transport Domain Provides the transport backbone and routing/

switching fabric for transporting packets across theVoIP network.Devices like routers and switches belong to thisdomain. Devices that provide Quality of Service (QoS) mechanisms andpolicies for the transport also belong to this domain.


6/68

b. Interworking Domain Domain are primarily responsible for the transformation of

signaling or mediareceived from external networksinto aform that can be sent among the various entities in theVoIP network and vice versa.

Consists of devices like : Signaling Gateways(signaling transport conversion between

different transport layers),

Media Gateways(media conversion between different transportnetworks and/or different media), Interworking Gateways(signaling interworking on the same

transport layer but with different protocols).

c. Non-IP Access Domain Domain that applies to non-IP terminals and wireless radionetworks that access the VoIP network.

Consists of :

Access Gatewaysor Residential Gatewaysfor non-IP

terminals or phones.


7/68

ISDN terminals, Integrated Access Devices (IADs) for DSL

networks, Cable Modem/Multimedia Terminal Adaptors

(MTAs) for HFC networks, and Media Gateways for a GSM/3G mobile radio

access network (RAN).Note: that the IP terminals, like a SIP phone, will directly connect to the IP

Transport Domain, without going through an Access Gateway.

2. Call Control & Signaling Plane It controls the major elements of the VoIP network,

especially in the Transport Plane. Carry out call controlbased on signaling messagesreceived from the Transport Plane, handle establishmentand teardownof media connectionsacross the VoIPnetwork by controlling components in the Transport

Plane.


8/68

Consists of devices like : Media Gateway Controller (a.k.a. Call Agent or Call

Controller), Gatekeepers and

LDAP servers.

3. Service & Application Plane Provides the control, logic and execution of one or more

services or applications in a VoIP network. Control the flow of a call based on the service execution

logic. They achieve this by communication with devices inthe Call Control & Signaling Plane.

Service & App Plane consists of devices like : Application Servers and Feature Servers.Service & App Planemay control specialized bearer components, such

as

Media Servers, that perform functions like conferencing, IVR, toneprocessing, and so on.


9/68

4. Management PlaneIt functions such as : Subscriber and service provisioning,

Operational support, Billing and Other network management tasks are handled.

It can interact with any or all of the other three planes throughindustry standard (e.g. SNMP) or proprietary protocols and

APIs.


10/68

Functional Entities

The diagram above shows 12 different functions. Understanding the autonomy of

all 12 functions is an important characteristic of the ISC Reference Architecture.


11/68

1).Media Gateway Controller Function(MGC-F) a.k.a. Call Agent or Call Controller

Provides the call state machinefor endpoints. Its primary role

is to provide the call logic and call control signalingfor oneor more media gateways.

Maintains call statefor every call on a media gateway May maintain bearer statesfor bearer interfaces on the

MG-F Communicates bearer messagesbetween two MG-Fs,as well as with IP phones or terminals

Acts as conduit for media parameter negotiation Originates/terminates signaling messagesfrom

endpoints, other MGC-Fs and external networks May interact with the AS-Ffor the purposes of

providing a service or feature to the user May managesome network resources (e.g. MG-F ports,

bandwidth etc.)


12/68


13/68

4).Call Routing and 5).Accounting Functions(R-F/A-F) R-F provides call routing information to the MGC-F, while the

A-F : collects call accounting information for billing

purposes. A-F can also have a broader role embodied by the common AAA

functionality (authentication, authorization andaccounting) in remote access networks.

Primary role of both functions is to respond to requests fromone or more MGC-Fs, directing the call or its accounting to

terminating endpoints (other MGC-Fs) or services (AS-Fs)


14/68

R-F/A-F Characteristics : Provides routingfunction for intra- and inter-network call

routing (R-F) Produces details of each session for billingand planning

purposes (A-F) Provides sessionmanagement and mobilitymanagement May learn routing informationfrom external sources May interact with the AS-Ffor the purposes of providing a

service or featureto the user May operate transparently to the other entities in the

signaling path Many R-Fs and A-Fs can be chained together in a

sequential or hierarchical manner The R-F/A-F is often integrated with the MGC-F. However,just as is the case with the ASF,

An integrated R-F/A-F/MGC-F can also request services ofan external R-F/A-F.

h ll d i ll i


15/68

The A-F collects and emits per-call accountinginformation. The AS-F emits accounting information forenhanced services, such as conferences and premiuminformation services.

Applicable protocols for the R-F include ENUMandTRIP

Applicable protocols for the A-F include RADIUSandAuC(for mobile networks)

6).SIP Proxy Server Function (SPS-F)The most common embodiment of the R-F and A-F is as a SIPProxy Server. For this reason, the ISC recognizes a separate SIP

Proxy Server Function (SPS-F).


16/68

7).Signaling Gateway Function (SG-F) and8).AccessGatewaySignaling Function (AGS-F) SG-Fprovides a gateway for signaling between a VoIP

network and the PSTN, whether SS7/TDM- or BICC/ATM-based. For wireless mobile networks, the SG-F also providesa gateway for signaling between an IP-based mobile corenetwork and PLMN that is based on either SS7/TDM orBICC/ATM.The primary role of the SG-F is to encapsulate andtransport PSTN (ISUP or INAP) or PLMN (MAP or CAP)signaling protocols over IP.

AGS-F provides a gateway for signaling between a VoIP

network and circuit-switched access network, whether V5-or ISDN-based.

For wireless mobile networks, the AGS-F also provides agateway for signaling between an IP-based mobile core

network and PLMN that is based on either TDM or ATM.

S Ch i i


17/68

AS-F Characteristics: May request the MGC-F to terminate calls/sessions for certain

applications (e.g. voice mail or conference bridge) May request the MGC-F to re-initiate call features (e.g. find

me/follow me or pre-paid calling card) May modify media descriptions using SDP May control an MS-F for media handling functions May be linked to Web applications or have Web interfaces May have an API for service creation

May have policy, billing and session log back-end interfaces May interface with MGC-Fs or MS-Fs May invoke another AS-F for additional services or to build

complex, component-oriented applications May use the services of an MGC-F to control external resources Applicable protocols include SIP, MGCP, H.248, LDAP, HTTP, CPL

and XML Applicable open APIs include JAIN and ParlayNote: Often the combination of the AS-F and the MGC-F provides enhanced call control services, such as networkannouncements, 3-way calling, call waiting and so on. Rather than connecting the AS-F and MGC-F with a protocol,

vendors often use an API between the AS-F and MGC-F when they are implemented in a single system. In thisembodiment, the AS-F is known as a Feature Server.

AGS F Ch i i


18/68

AGS-F Characteristics : Encapsulates and transports V5 or ISDN signaling

protocols (e.g. SS7) using The interface from the AGS-F to theother entities is a protocol interface when the AGF-F andMGC-F or other AGF-F are not co-located (e.g. SIGTRAN)

SIGTRAN to the MGC-F

For mobile networks, encapsulates & transports BSSAP orRANAP signaling protocols (e.g. SS7) using SIGTRAN to the MGC-F

One MGC-F may serve many AGS-Fs Applicable protocols include SIGTRAN, M3UA, IUA andV5UA over SCTP

9).Application Server Function (AS-F)The AS-F is the application execution entity. Its primary role isto provide the service logic and execution for one or moreapplications and/or services.

Th i l f th AGS F i t l t d t t


19/68

The primary role of the AGS-F is to encapsulate and transportV5 or ISDN (wireline), or BSSAP or RANAP (wireless) signalingprotocols over IP.

R-F/A-F Characteristics : Encapsulates and transports PSTN signaling protocols (e.g.

SS7) using SIGTRAN to the MGC-F or another SG-F For mobile networks, encapsulates and transports PSTN/

PLMN signaling protocols (e.g. SS7) using SIGTRAN to theMGC-F or another SG-F

The interface from the SG-F to the other entities is aprotocol interface when the SG-F and MGC-F or other SG-

F are not co-located (e.g. SIGTRAN) One SG-F can serve multiple MGC-Fs Applicable protocols include SIGTRAN, TUA, SUA and

M3UA over SCTP

M f i li d di t d t ti


20/68

May perform signaling and media event detectionfunctions such as DTMF detection,

on/off-hook detection, voice activity detection, etc. Manages its own the media processing resources required

to provide the functionality mentioned above May have the ability to perform digit analysis based on a

map downloaded from the MGC-F Provides a mechanism for the MGC-F to audit the state and

capabilities of the endpoints Is not required to maintain the call state of calls passingthrough the MG-F; the MG-F only maintains the connectionstate of the calls it supports

A SIP phone is an MG-F and MGC-F in a single box A SIP-capable gateway is an MG-F and MGC-F in a single

box Hair pinning of a call by the MG-F directed toward the

source network may occur under control of the MGC-F

Applicable protocols include RTP/RTCP, TDM, H.248 and

10) S i C l F i (SC F)


21/68

10).Service Control Function (SC-F) SC-F exists when the AS-F controls the service logic of a

function. For this reason, the ISC recognizes a separate SC-F.

Examples of SC-F protocols include : INAP, CAP and MAP;open APIs include JAIN and Parlay.

11). Media Gateway Function: (MG-F) MG-F interfaces the IP network with an access endpoint or

network trunk, or a collection of endpoints and/or trunks. MG-F serves as the gateway between the packet and

external networks, such as the PSTN, mobile network, etc.

For example, the MG-F could provide the gatewaybetween :

an IP and circuit network (e.g. IP to PSTN), or between two packet networks (e.g. IP to 3G or

ATM).

It i l i t t f di f t i i


22/68

Its primary role is to transform media from one transmissionformat to another, most often between : circuits and packets, ATM packets and IP packets, or

analog/ISDN circuits and packets as in a residentialgateway.

MG-F Characteristics:

Always has a master/slave relationship with the MGC- Fthat is achieved through a control protocol such as MGCPor MEGACO

May perform media processing functions such as media

transcoding, media packetization, echo cancellation, jitterbuffer management, packet loss compensation, etc. May perform media insertion functions such as call

progress tone generation, DTMF generation, comfort noisegeneration, etc.

12 M di S F ti (MS F)


23/68

12.Media Server Function (MS-F)The MS-F provides media manipulation and treatment of apacketized media stream on behalf of any applications. Itsprimary role is to operate as a server that handles requestsfrom the AS-F or MGC-F for performing media processing onpacketized media streams.

MS-F Characteristic: Support for multiple codecs and transcoding Support for control by multiple AS-Fs or MGC-Fs Support for multiple concurrent capabilities:

o digit detection

o streaming of tones and announcements (anymultimedia file)

o algorithmic tone generationo recording of multimedia streamso speech recognitiono speech generation from text


24/68

o speech generation from texto mixing (conference bridge)o fax processing

o voice activity detection and loudness reportingo scripted combinations of the above

Performs under the control of an AS-F or MGC-F through acontrol protocol, with either :

tight coupling (resource control) or loose coupling(function invocation or scripts) Applicable protocols include SIP, MGCP and H.248


25/68

MGC Building Blocks

N t k E l


26/68

Network Example Wireline


27/68

All-IP Network


28/68

VoIP Tandem Switching


29/68

POTS Carried over

IP

Access Net ork (V5/ISDN) o er IP


30/68

Access Network (V5/ISDN) over IP

Cable Network (e g PacketCable) over IP


31/68

Cable Network (e.g. PacketCable) over IP


32/68

VoDSL and IAD over IP


33/68

Wireless (3GPP R99 Special Case NGN)


34/68

Wireless (3GPP R2000 General Case all IP)

WCDMA Mobile Network


35/68

WCDMA Mobile Network


36/68

3GThird Generation

3GPP3G Partnership Project (UMTS)

AAAAuthentication, Authorization and Accounting (IETF)A-F(Call) Accounting Function (ISC)

ADSLAsymmetric Digital Subscriber Line

AGAccess Gateway

AGS-FAccess Gateway Signaling Function (ISC)

AINAdvanced Intelligent Network

ANAccess NetworkAPIApplication Programming Interface

ASApplication Server

AS-FApplication Server Function (ISC)

ATMAsynchronous Transfer Mode

ATU-RADSL Terminal Unit-Remote

AuCAuthentication Center (GSM)BGBorder Gateway

BICCBearer Independent Call Control (ITU Q.1901)

BSSAPBase Station Subsystem Application Part (GSM, 3GPP)

CACall Agent

CA-FCall Agent Function (ISC)

Acronyms


37/68

CAMELCustomized Applications for Mobile Network Enhanced Logic (GSM)

CAPCAMEL Application Part (GSM, 3GPP)

CLICommon Language Infrastructure

CMCable Modem

CMTSCable Modem Termination System (DOCSIS, PacketCable)COPSCommon Open Policy Protocol (IEFT RFC 2748)

CPLCall Processing Language

DiffServDifferentiated Services

DOCSISData Over Cable System Interface Specification

DQoSDynamic Quality of Service

DSLDigital Subscriber LineDSLAMDSL Access Multiplexer

DTMFDual Tone/Multiple Frequency

ENUME.164 Numbering (IETF RFC 2916)

FSFeature Server

GGSNGateway GPRS System Node (GPRS, 3GPP)

GKGatekeeperGMSCGateway Mobile Services Switching Center (GSM, 3GPP)

GPRSGeneral Packet Radio Service

GSMGlobal System for Mobility

HFCHybrid Fiber/Cable

HLRHome Location Register (GSM, 3GPP)

HSSHome Subscriber System (3GPP)


38/68

HTTPHyper Text Transport Protocol (IETF)

IADIntegrated Access Device

IETFInternet Engineering Task Force

INIntelligent Network

INAPIntelligent Network Application ProtocolISDNIntegrated Services Digital Network

ISUPIntegrated Services Digital Network User Part (SS7)

ITUInternational Telecommunications Union

IUAISDN User Adaptation

IVRInteractive Voice Response

IW-FInter-working Function (ISC)JAINJava Application Interface Network

LDAPLightweight Directory Access Protocol (IEFT)

M3UAMTP3 User Adaptation (IETF SIGTRAN)

MAPMobile Application Part (GSM, 3GPP)

MEGACOMEdia GAteway COntrol (IETF RFC 3015 or ITU H.248)

MGMedia GatewayMGCMedia Gateway Controller

MGC-FMedia Gateway Controller Function (ISC)

MGCPMedia Gateway Control Protocol (IETF RFC 2705)

MG-FMedia Gateway Function (ISC)

MMASMobile Multimedia Application Server (3GPP)

MMCSMobile Multimedia Call Server (3GPP)


39/68

MPLSMulti-Protocol Label Switching

MSMedia Server

MSCMobile Services Switching Center (GSM, 3GPP)

MS-FMedia Server Function (ISC)

MTAMultimedia Terminal Adaptor (PacketCable)NCSNetwork Call/Control Signaling (PacketCable)

NGNNext Generation Network

OEMOriginal Equipment Manufacturer

OSAOpen Service Access (3GPP)

OSSOperational Support System

PBXPrivate Branch eXchangePLMNPublic Land Mobile Network (3GPP, UMTS)

POTSPlain Old Telephone Service

PSEPersonal Service Environment (3GPP)

PSTNPublic Switched Telephone Network

QoSQuality of Service

RANRadio Access NetworkRANAPRadio Access Network Application Part (3GPP)

R-F(Call) Routing Function (ISC)

RFCRequest For Comment (IETF)

RGResidential Gateway

RSVPResource ReSerVation Protocol (IETF)


40/68

RTCPReal Time Transport Control Protocol (IETF)

RTPReal Time Transport Protocol (IETF RFC 1889)

SC-FService Control Function (ISC)

SCPService Control Point

SCTPStream Control Transmission ProtocolSDPSession Description Protocol

SGSignaling Gateway

SG-FSignaling Gateway Function (ISC)

SGSNServing GPRS System Node (GPRS, 3GPP)

SIGTRANSIGnaling TRANsport (IETF M3UA, IUA, SUA, V5UA Drafts)

SIPSession Initiation Protocol (IETF)SIP-TSIP For Telephony (IETF Draft)

SNMPSimple Network Management Protocol

SPS-FSIP Proxy Server Function (ISC)

SS7Signaling System 7

SUASCCP User Adaptation (IETF SIGTRAN)

TCAPTransaction Capability Application Part (SS7)TDMTime Division Multiplexing

TGTrunk or Trunking Gateway

TGCPTrunking Gateway Control Protocol

TLAThree-Letter Acronym

TRIPTelephony Routing over IP (IETF RFC 2871)


41/68

TUATCAP User Adaptation (IETF SIGTRAN)

UMTSUniversal Mobile Telecommunications System

V5UAV5 User Adaptation (IETF SIGTRAN)

VADVoice Activity Detection

VLRVisitor Location Register (GSM, 3GPP)VoDSLVoice over DSL

VoIPVoice over IP

WAPWireless Application Protocol

WCDMAWideband Code Division Multiple Access

XMLExtensible Markup Language

Example of Implementation


42/68

Example of Implementation

IP Clients and

Terminals

SS7oIP

SS7

Switch STP

PSTN Networks

IP Core Networks(ISP)

ManagementSystem

MGCP/H.248

AccessGateway

TrunkGateway

Signaling

Gateway

Softswitch(MGC)

Internet

ApplicationServer

IP CustomerPremises

SIEMENSNIXDORFSIEMENSNIXDORF

[2] Sumber : Siemens, Surpass Packet

ISDN-BRI

SIEMENSNIXDORF

SIEMENSNIXDORF

Analog phone

ISDN Terminals

xDSL Terminals

SIEMENSNIXDORF

Analog phone

ISDN-BRI

SIEMENSNIXDORF

ISDN Terminals

xDSL Terminals

SIEMENSNIXDORF


43/68

The

SoftswitchSun MicroSystem version

EXTRA SLIDE

S ft it h C t


44/68

Softswitch Components


45/68

1. Media Gateway Controller (MGC) / Call Agent(CA) / Softswitch

Hold call processing rules by controls SG & MG(to perform the job) : call set up & tear down.

Interfaces to the OSS

Interworking with other networks

3. Media Gateway (MG)

Gateway between SS7 network and the nodesmanaged by the Softswitch

2. Signaling Gateway (SG)

Handels the media data payload includingcodec/compression

Supports legacy telephony (PSTN) : CAS/ISDN


46/68

3. Media Server

Perform peripheral functions such as DSP, IVRetc

Provide all the revenue generating features andservices like billing, multi-party conferencing etc.

It uses the resources and related services locatedon other components of the Softswitch

It may also support certain services to meetcertain implementation necessity e.g.:GateKeeper.

4. Feature Server)


47/68

a Functional Requirements


48/68

a. Functional Requirements

Call control engine

Voice call establishment protocols : H.323, SIP

Media control protocols : MGCP, Megaco/H.248 Class of service and quality of service control

SS7 control protocol: SIGTRAN (SS7 over IP)

SS7 processing (when using SigTran)

QoS related protocol message handling such as RTCP Routing, including :

Routing component : local dial plan (E164 to port mapping)

Digit analysis overlap and/or enblock signaling

Digit translation support for IP, FR, ATM and other networks

Call Detail Records (CDR) for billing Bandwidth management control

Provisioning for Media Gateways: Assignment and real time configuration of DSP resources

DS0 channel assignments

Voice transmission (coding, compression, and packetization)

P i i i f Si li G t


49/68

b. System Characteristic

Provisioning for Signaling Gateways: SS7 variants

Process Timers

Linkset configuration

Point code or routing configuration Gatekeeper registration

It is CPU intensive. A multi-processor system is mostpreferred.

A large in-memory database required. Its enable multipleprocesses to live in memory.

It deals mostly with IP traffic. A sufficient amount of high-speed connectivity may be required.

A dual-redundancy approach for network connectivity isnormally required.


50/68

It requires support for a variety protocols.

Disk storage is primarily used for logging.

It must be highly available. There are several methods for

achieving this.

2. Signaling Gateway (SG)

Creates a bridgebetween the SS7 network and an IPnetwork

Under the control of the Gateway Controller a Signaling

Gateway causes a Softswitch to appear like an ordinary

SS7 point code(SS7 node) in an SS7 network.

The Signaling Gateway only handles SS7 signaling;

Media Gateway handles the voice circuits established by

the SS7 signaling mechanism.

SIGTRAN defines a suite of protocols and User Adaptation


51/68

SIGTRANdefines a suite of protocols and User Adaptation

layers for ransporting signaling information over IP-based

networks.

If SigTran is used as the protocol between the Gateway

Controller and the Signaling Gateway, then only MTP1,

MTP2, and SigTran reside on the Signaling Gateway. In this

case, MTP3 and higher protocol stacks will reside on the

Gateway Controller.

A Signaling Gateway usually supports the following layers :

SCTP, which is responsible for reliable signaling

transport, streaming, congestion avoidance and control

M3UA, which supports the transport of ISUP, SCCP, andTUP messages over IP

M2UA, which supports congestion control and the

transport of MTP3 messages

IUA, which supports the Q.931/Q.921 interface

M2Peer, which supports the MTP3-to-MTP2 interface


52/68

If a proprietary event interface is used between the

Gateway Controller and the Signaling Gateway, then the

entire SS7 protocol stack resides on the Signaling

Gateway (including MTP3, ISUP, SCCP, and TCAP). A signaling gateway establishes the protocol, timing, and

message-framing requirement of the SS7 network, as well

as the functional equivalents within the IP network.

Refer to Appendix B for background details on Signaling

and SS7.


A Signaling Gateway must support the following functions :

It must provide physical connectivity to the SS7 networkvia a TI/El or Tl/V.35 physical connection

It must be able to transport SS7 information betweenGateway Controller and Signaling Gateway via an IPnetwork


53/68

It must provide a transmission path for voice, video, andoptionally data. (Data transmission may be supportedwithin the Media Gateway)

Provide Highly Available SS7 operation fortelecommunication services


A Signaling Gateway has the following system characteristics: It is I/O intensive, but not very CPU intensive.

A maximum amount of memory should be available to hold

state information, configuration information, the point code

map, alternate routes, etc. A disk storage is primarily used for logging; a small

capacity may be adequate.


54/68

The Ethernet interface (to the IP network) may require dual

redundancy.

It may interface with the SS7 network by using a T1/E1,with a minimum 2 D-channels, and a maximum 16 D-

channels.

Performance and flexibility can be increased using a H.110

or H.100 bus.

High Availability is a requirement, multiple Signalling

Gateways or signalling links are available. Redundancy is

built into SS7 networks by design.

3 Media Gateway (MG)


55/68

3. Media Gateway (MG)

Provides transport media (voice, data, fax, and video)

between the IP packet network and the PSTN.

Typically, DSP perform :

analog-to-digital conversion

voice/audio code compression

echo cancellation

silence detection

suppression

comfort noise generation

out-of-band DTMF signal transport, etc.

DSPs control the translation of voice into packets for the

IP network Appendix C has more details on Media encoding of

digitized audio.

a Functional Requirements


56/68


A Media Gateway should support the following :

Transmission of voice data using the RTP transmission

protocol.

DSP resource and T1 timeslot allocation under control of

the Gateway Controller, as a result of MGCP or MEGACO

messages. SIP is preferred, although optional.

Manage DSP resources to provide voice and packetfunctions for the services mentioned above.

Support for legacy protocols such as loop-start, ground-

start, E&M, CAS, QSIG, and ISDN over T1.

Support of T1 clear channel configuration for transferringvoice traffic payload in SS7 networks.

Managing T1 resources and links.

Hot plug of DSP and Tl cards.


57/68

Redundancy and HA strategies for Media Gateway

software.

Ability to scale the Media Gateway including the ports,

cards, and nodes without impacting other Softswitch

components.

A Media Gateway has the following system characteristics:

It is I/O intensive; I/O scalability is required.

The maximum amount of memory may be necessary to

hold state information, configuration information, MGCPmessages, DSP libraries, etc.

A disk storage is primarily used for logging; a small

capacity may be adequate.



58/68

The Ethernet interface (to the IP network) may require

redundancy.

The interface to the TDM network may need to span several

T1/E1 interfaces.

Densities of 120 ports (DS0s) are normal. Typically these

interfaces incorporate onboard DSPs to perform several

types of compression.

H.110 bus can be leveraged for localized system flexibility. A High Availability configuration may scale the user density.

4 Media Server


59/68

4. Media Server

Usually separately from the Feature Server because

Media Server applications involve specialized media

processing (must support high-performance DSP hw).


A Media Server may have the following functional

requirements Basic voicemail functionality

Integrated fax mailbox, notification may use e-mail or pre-

recorded message.

Voice recognition capability if provided, e.g voice activity

dialing can route a voice-activated call by using database

lookups, and then route the call.

Video conferencing capability including video conference

setup and transmission via H.323 or SIP.

Video conferencing capability including video


60/68


conference setup and transmission via H.323 or SIP.

Speech-to-text capability to send text to a persons

email account or pager device by using voice input.

Speech-to-Web feature converts key words into textstrings, which can be used for Web lookup or Web

access.

Unified messaging is the ability to read voice, fax, and

email messages via the same user interface.

A Media Server has the following system characteristics:

It is CPU intensive, as it may handle a lot of MGCPmessage traffic.

Several implementation options exists with local or co-

located DSP resources or native CPU


61/68

The maximum amount of memory may be required for in-

memory databases, large local caching buffers,

extensive libraries, and so forth.

A disk storage used for logging can be of small capacity.If DSP libraries, speech patterns are stored, adequate

storage is needed on Disk.

It handles mostly IP traffic, if DSP resources are used for

speech processing. It typically can be clustered (n+m type) for high

availability.

5 Feature Server


62/68

5. Feature Server

Feature Server is defined as an application-level

server that hosts, a set of business services.

This may be also referred to as a Business Application

Server.

Since most feature servers host business services and

communicate over IP networks, there are no

softswitch-specific constraints on how to divide orgroup application components.

These value-added services can either be part of the

call agent, or they can be deployed separately. The applications communicate with the Call Agent

through protocols such as SIP, H.323 and others.

These applications are usually hardware-independent

but they may require extensive databaseaccess.


63/68

Examples of feature services: 800 number serviceThis service provides lower call

charges for high levels of incoming calls.

Translation of the 800 number to an actual target

telephone number is provided by the 800 number

database. The called party pays for these calls.

900 number serviceThis service provides

information, contest call-in, and public opinion polls.The caller pays for these calls.

Billing serviceCall detail records (CDRs) are created

by the call agent. The CDR program has many billing

features, such as the ability to apply rates based online type, time-of-day, etc.

This service may offer the customer access to their

billing record on demand via a voice call or a Web

request.

H 323 G t K Thi i t ti


64/68

H.323 GateKeeperThis service supports routing

across domains. Each domain (which is handled by a

Softswitch) can register its phone numbers and trunk

access numbers with the GateKeeper via H.323. TheGateKeeper provides the call routing service (and digit

translation) for each H.323 endpoint.

The GateKeeper may provide billing and bandwidth

management control to the Softswitch. Calling card servicesThis service allows a caller to

access long distance service via a traditional

telephone.

Billing, PIN authentication, and routing support are

provided by the service. Call authorizationThis service establishes Virtual

Private Network (VPN) using a PIN authorization.

VPNThis service establishes virtual private (voice)


65/68

s se ce estab s es tua p ate ( o ce)

networks. These are private networks which can offer the

following features:

Dedicated bandwidth (via leased high-speed networks)

Guaranteed Quality of Service (QoS)

Enhanced features that do not necessarily adhere to

standards

Private dialing plans

Secure encrypted voice transmission Centrex servicesWith this service, the service provider

offers features usually found only in large central offices and

PBX systems, such as:

Basic features: call waiting, forward, transfer, park, hunt,and voicemail

Convenience features: autodial, speed dial, calling line ID

Customized private dialing plans

Secure encrypted voice transmission

Call center services:A t ti ll di t ib ti hi h ffi i tl t


66/68

Automatic call distribution, which efficiently routes

incoming calls to multiple destinations

Answering agents based on a configured policy

management schemeSystem Characteristic

A Feature Server has the following system characteristics:

It typically requires moderate to high CPU utilization. This is

dependent upon the specific application. A large onboard memory is desirable for low latency.

It may require CPU scalability to scale with traffic and

application enhancements.

Several databases may be located at the Feature server. Adequate disk storage may be budgeted for the application

needs depending on the nature of the application. 100GB to

2TB range for a typical voice mail bank.

The Ethernet interface (to the IP network) may be

implemented with dual redundancy.


67/68

Example of Implementation :


68/68

p p

Soffswitch Integration using Compact PCI Technology (cPCI)

modul 2 softswitch

Documents

nonip access domain

interworking domain

gkip transport domain

transport plane devices

transport backbone

transport mechanisms

ip backbone

application of softswitch