Title: 6. Next Generation Networks 6.1. Transition to NGN 6.2. Key drivers of NGN development 6.3. Evolution of networks
16. Next Generation Networks6.1. Transition to
NGN6.2. Key drivers of NGN development 6.3.
Evolution of networks architecture to NGN 6.4.
NGN architecture 6.5. Main NGN protocols and
building blocks
26.1. Transition to NGN First wave
- Growth of Internet and other IP-based networks
with their - requirements for bandwidth and capacity has
driven rapid - innovation in telecommunication access and
transport networks - Examples
- leveraging copper wire last-mile networks
through digital subscriber line (DSL)
technologies - re-architecturing of cable networks to support
IP services - advances in optical networking technologies
(e.g. PON)
3Convergence of Telephony World and Internet World
4Transition to NGN Second wave
- Ongoing trend towards integration
interoperability of IP- - based and PSTN network services and applications
- Emergence of differentiated Quality of Service
IP-based services - Managed end-to-end performance needed for new
applications - requiring real-time traffic (e.g., video, voice)
- New network management, QoS, traffic
engineering, pricing - accounting models
5Transition to NGN Third wave
- Evolution of current PSTN, mobile, wireless and
- IP-based networks to unified Next Generation
Networks - providing both Internet and carrier-grade
telecommunications - networks and services offerings with QoS
- Transition to Third wave
- Ubiquitous Pervasive Networks
- anybody, anytime, anywhere
- Global Information Infrastructure (GII) ITU,
1995 - EII ETSI Project (1995)
- ETSI 3GPP (1998)
- 3GPP activity (FMC and IMS development)
- TISPAN Project (ETSI, 2003)
- TISPAN - Telecoms Internet converged
Services Protocols for Advanced Networks - ITU NGN 2004 Project
- Y.1xx ITU-T SG 13 NGN Architecture,
Evolution and Convergence
6One unified network for everything
Transition to NGN Third wave
Today
Tomorrow
Internet
Telephone network
IP-Network
Mobile radio network
- Multimedia Access - Advantages
- easy to handle
- reliable
- mobile
7The Unified NetworkThe Vision
Situation Today
Target Solution
Voice Fix and Mobile
The Unified Multi Service Network
FR
IP
...
ATM
8The Unified NetworkThe Data Migration
Voice
The Unified Multi Service Network
FR
IP
...
ATM
9The Unified NetworkThe Voice Migration
Voice
The Unified Multi Service Network
FR
IP
...
A new network concept supporting voice in a
packetized environment is required The Next
Generation Network
ATM
10ITU-T definition of NGN (Y.2001, Feb 2004)
- A Next Generation Network (NGN) is a
packet-based network - able to provide services including
Telecommunications Services - and able to make use of multiple broadband,
QoS-enabled - transport technologies and in which
service-related functions - are independent from underlying transport-related
technologies. - It offers unrestricted access by users to
different service - providers. It supports generalized mobility which
will allow - consistent and ubiquitous provision of services
to users. - One of the primary goals of NGN is to provide a
common, unified, - and flexible service architecture that can
support multiple types of - services over multiple types of transport
networks.
11NGN is the public packet-based network with the
following main features
- Layered architecture
- Open interfaces between the layers and all other
networks - Seamless control of multiple transport
technologies - Centralized intelligence
12NGN Characteristics
- The NGN is characterized by the following
fundamental aspects - Packet-based transfer in the core NGN network
- Support for a wide range of services,
applications and mechanisms - (including real time/ streaming/ non-real time
services and multi-media) - Independence of service-related functions from
underlying transport - technologies
- Separation of control functions among bearer
capabilities, call/session, and - applications/services
- Broadband capabilities with required end-to-end
QoS - Interworking with legacy networks via open
interfaces - Generalized mobility
- Unrestricted access by users to different service
providers - Services convergence between Fixed/Mobile
- Compliance with all Regulatory requirements, for
example concerning emergency communications,
security/privacy, etc.
136.2. Key drivers of NGN development
- Short Term objective Create new revenue
possibilities - Removal of boundaries between voice and data
opens the way to new kind of services - Can be realized relatively quickly with limited
investments - Long Term objective Realize cost savings
- Simpler network
- More efficient network
- Cheaper network components
- Full benefit only realized when all separate
networks have fully migrated towards to the
target solution
14Key drivers technologies and services
Next Generation Network
15NGN key drivers From IP Technology to User and
Application Centric
- User demands
- easiness to use and personalization of services
- seamless service regardless of the access
technology - a beautiful garden offering valuable services
with security - openness to the entire Community
- Operator challenges need to be addressed
- need to manage complexity to deliver simplicity
- platform for convergence of services and
technologies - support of different device and access
technologies - revenue opportunities by mobility and nomadicity,
worldwide use - support migration from existing technologies
16NGN services
17NGN Services
- Voice Telephony NGN will likely need to support
various existing voice telephony - services (e.g., Call Waiting, Call Forwarding,
3-Way Calling, various IN features, - various Centrex features and etc.).
-
- Data Services Allows for the real-time
establishment of connectivity between - endpoints, along with various value-added
features - Multimedia Services Allows multiple parties
to interact using voice, video, and/or - data.
- Virtual Private Networks (VPNs) Voice VPNs
improve the interlocation networking - capabilities of businesses by allowing large,
geographically dispersed organizations to - combine their existing private networks with
portions of the PSTN, thus providing - subscribers with uniform dialing capabilities.
- .
18NGN Services
- Public Network Computing (PNC) Provides public
- network-based computing services for businesses
and - consumers.
- Unified Messaging Supports the delivery of
voice mail, email, - fax mail, and pages through common interfaces.
- Information Brokering Involves advertising,
finding, and - providing information to match consumers with
providers. - E-Commerce Allows consumers to purchase goods
and - services electronically over the network. Home
banking and - home shopping fall into this category of
services. This also - includes business-to-business applications
19NGN Services
- Call Center/Web Contact Services A subscriber
could place a call to a call/Web contact center
agent by clicking on a Web page. - Interactive gaming Offers consumers a way to
meet online and establish interactive gaming
sessions (e.g., video games). - Distributed Virtual Reality Refers to
technologically generated representations of real
world events, people, places, experiences, etc., - Home Manager With the advent of in-home
networking and intelligent appliances, these
services could monitor and control home security
systems, energy systems, home entertainment
systems, and other home appliances.
20Applications
- VoIP
- Web Browsing
- Chat
- Instant Messaging
- WAP Browsing
- Multimedia Messaging
- VoD Movies/Gaming/News/Sports/Training
- Video Telephony
- Video Broadcasting
- Video Conferencing
- Video Collaboration
- IP PBX/Centrex
- Email
21NGN Today Facing the Multi-Application/Multi-Acc
ess Challenge
226.3. Evolution of networks architecture to NGN
- The unified network will use packet-based
technology as the common transport mechanism - Data is the fastest growing segment due to
- Success of Internet
- Growing use of E-mail
- Growing data traffic between business users
- Data should be handled in the most efficient way
- Packet technology is the best way to transport
data - Packet technology is only technology that allows
simultaneous delivery of different information
streams towards one and the same end-point on one
single connection
23- Evolution of network architecture
-
- Traditional telephony - Circuit switch based PSTN
24Evolution of network architecture
Circuit Switched PSTN Packet Switched IP
network (VoIP Gateway) SG Signaling
gateway MGC Media gateway controller MG Media
gateway
25Evolution of network architecture
- Completely IP-oriented network
26Convergence of network technologies and media
Nx64 kbps
276.4. NGN architecture
Management
System Management Servers
Application Servers
Applications
Softswitches Signaling gateways
Control
Packet Network
Core
MediaGateway
Mobile
PSTN
MediaGateway
Edge
Broadband
UTRAN
Access
CO
DSL
WLL
Cable
Mobile Users
Remote Office/SOHO
Enterprise Customers
ResidentialUsers
28NGN architecture - NGN functional model
Application/Management Part
Application Servers Management Servers
Open Services Interfaces/API
Session Part (Call control)
Softswitches
Media Gateway Control
Transport Layer
Media Gateways
API - Application Programming Interface
29NGN architecture
Services
Transport
30ITU-T NGN architecture (Y.1001) and corresponding
protocols
IP Network
IW Functions
PSTN/ISDN
- Softswitch includes MGC, SG
- Media Gateway is protocol converter
- Media Gateway Controller is master
- controller of a media gateway
- Intelligent Database - Network directory,
- Billing, Call records
-
Intelligent Database (ID)
.
.
ID/SG
ID/MGC
API
.
.
Signaling Gateway (SG)
H.323/SIP/SIP-T/ SIGTRAN
.
CC7/SS7 ISUP
SG/MGC
MG Controller (MGC)
.
MGC/MGC
.
MGC/MG
MGCP/Megaco(H.248)
.
.
Media Gateway (MG)
RTP Packet Flow (Voice/Data/MM)
TDM Flow (Voice)
316.5. Main NGN protocols and building blocks
32Main control protocols
- Call Control (Session Control)
- The ability of a network element to establish new
calls. - A call in the next generation network can be
viewed as - a session in which the session establishes either
a voice - conversation or, ultimately, a multimedia (audio
plus video) - stream.
- There are two primary call control protocols
unique to - packet-based networks
- H.323
- SIP
33H.323, ITU-T
- H.323 - first call control standard for
multimedia networks. - Was adopted for VoIP by the ITU in 1996
- H.323 is actually a set of recommendations that
define how - voice, data and video are transmitted over
IP-based networks - The H.323 recommendation is made up of multiple
call control - protocols. The audio streams are transacted
using the RTP/RTCP - In general, H.323 was too broad standard without
sufficient - efficiency. It also does not guarantee
business voice quality
34SIP - Session Initiation Protocol, IETF (Internet
Engineering Task Force)
- SIP - standard protocol for initiating an
interactive user session that involves multimedia
elements such as video, voice, chat, gaming, and
virtual reality. Protocol claims to deliver
faster call-establishment times. - SIP works in the Session layer of IETF/OSI model.
SIP can establish multimedia sessions or Internet
telephony calls. SIP can also invite participants
to unicast or multicast sessions. - SIP supports name mapping and redirection
services. It makes it possible for users to
initiate and receive communications and services
from any location, and for networks to identify
the users wherever they are.
35SIP - Session Initiation Protocol, IETF
- SIP client-server protocol, Rq from clients, Rs
from servers. Participants are identified by SIP
URLs. Requests can be sent through any transport
protocol, such as UDP, or TCP. - SIP defines the end system to be used for the
session, the communication media and media
parameters, and the called party's desire to
participate in the communication. - Once these are assured, SIP establishes call
parameters at either end of the communication,
and handles call transfer and termination. - The Session Initiation Protocol is specified in
IETF Request for Comments (RFC) 2543.
36IN Control
- Feature servers provide IN control with legacy
central - offices and Softswitches.
- INAP (Intelligent Network Application Part) - a
member - of the family of SS7 application protocols.
- Additional IN protocols have also been developed
- for mobile networks (e.g. GSM-CAMEL).
37Gateway control
- The target of the Gateway control - to enable a
simple - media gateway implementation with intelligence
- centralized on a media gateway controller (which
is also - called a call agent or a Softswitch)
- Two gateway control protocols
- Media Gateway Control Protocol (MGCP) as the de
- facto standard
- H.248/Megaco as the ITU and IETF approved
standard.
38MGCP/Megaco/H.248
- MGCP - Media Gateway Control Protocol, IETF
Telcordia (formerly Bellcore)/Level 3/Cisco - MGCP control protocol that specifically
addresses the control of media gateways - Megaco/H.248 (IETF, ITU) - standard that combines
elements of the MGCP and the H.323, ITU (H.248) - The main features of Megaco - scaling (H.323) and
multimedia conferencing (MGCP)
39Media Control
- Media control is a form of device control used
for network - elements that are specialized for advanced media
processing. - Media control includes instructions to play and
record voice - files, collect and generate tones (including DTMF
touch-tones), - establish N-way conferences, perform fax
conversions, generate - text-to-speech, and perform speech recognition.
40Application Program Interface
- API - routing, billing, call control, and media
control on - the feature server and application server.
- The goal of the APIs is to enable
- 1. Service logic that is independent of network
protocols, - network deployment architecture, and reference
element - architecture to meet the service provider
requirement for - service ubiquity
- 2. Services that scale from an entry level
integrated - solution to a distributed network deployment
without - modifications, meeting the service provider
requirement - for low cost infrastructure
41Main transport protocols
- Real-Time Transport Protocol (RTP) and Real-Time
Control Protocol (RTCP) - RTP - for end-to-end network transport of
communications services requiring - real-time data (i.e., audio and/or video).
- Real-Time Control Protocol (RTCP) for data
transport monitoring -
- RTP and RTCP are designed to be independent of
the underlying network layers (e.g., - UDP/IP, MPLS, or ATM).
- RTP does not address resource reservation nor
does it guarantee quality-of-service - (QoS).
- Resource Reservation Setup Protocol (RSVP)
- Multi-Protocol Label Switching (MPLS)
-
- RTP routing over MPLS sessions
42NGN architecture possible NGN configuration
Network Manager
Application Server
SNMP
RADIUS
API (Parlay, LDAP)
Softswitch
SIP/SIP-T H.323/BICC
SG
SIGTRAN
SG
SS7 ISUP
SIGTRAN
ISUP
Softswitch
SIP
MGC
MGCP/Megaco/H.248
Gatekeeper/ Proxy Server
Media Gateway
Media Gateway
Core IP Network (QoS)
?.323/ IP Network
43B. NGN building blocks
- Media Gateway - protocol converter
- Media Gateway Controller - master controller of a
media gateway - Softswitch MGC SG
- Signaling Gateway
- Application Server Information Database (ID) -
Network directory, Billing, Call records,
Authentication, authorization, and accounting
(AAA) - Network Manager Operation, Administration,
Management (OAM) provides network elements
management from a centralized web interface
44Media Gateway (IETF RFC 3015)
- Media gateway (MG) protocol converter between
different types - of networks (Example MG between
circuit-switched voice - network - TDM flows, and the IP network - RTP
packet flows.) - MG processes incoming calls via requests to the
Application - Server using HTTP.
- The media gateway (MG) terminates IP and
circuit-switched - traffic. MGs relay voice, fax, modem and ISDN
data traffic over the - IP network using Quality of Service enabled IP
technology.
45Media Gateway (IETF RFC 3015)
- All types of traffic (voice, data, video)
- Control (from Media Gateway Controller) MGCP,
Megaco/H.248 - Interfaces STM-1to transport network, E1 to
PSTN Eth-Fast/Gb to - IP network
- Voice Packetization/Compression (Codecs ITU-T
G.711, G.723.1, G.726, G.729A - Echo cancellation ITU-T G.165, G.168
- QoS via DiffServ and ToS bits marking
- Mapping addresses E.164 IP address
46Softswitch
- Signaling Gateway
- Signaling Gateway (SG) offers a consolidated
signaling - interface - SS7 signaling point for the NGN
platform. - Also, SG supports a SIGTRAN interface (IETF SS7
telephony - signaling over IP) as well as IP Proxy functions
(SIP). - Media Gateway Controller
- MGC acts as the master controller of a media
gateway - Supervises terminals attached to a network
- Provides a registration of new terminals
- Manages E.164 addresses among terminals
47Signaling Gateway Function
- Several millions BHCA
- Several hundreds controlled trunk ports
- Control MGCP, MEGACO, SIP
- Signaling ISUP, H.323, SIP, SIP-T, INAP, SIGTRAN
- Mgmt SNMP
IP Signaling
SS7 Signaling
SIGTRAN
ISUP
IP Network
PSTN
Signaling Gateway
48Application Server
- Application server provides the applications
(i.e., service logic) for new and - innovative services such as unified messaging,
conferencing, speech dial tone, - and multimedia messaging services. Application
servers are typically based on - advanced Java tool environments that provide
multi-modal integration of voice - and data.
- Application Server generates application
documents (VoiceXML pages) in - response to requests from the Media Gateway via
the internal Ethernet - network.
- The application server leverages a web
application infrastructure to interface - with data stores (messages stores, user profile
databases, content servers) - to generate documents (e.g., VoiceXML pages).
- AS provide interoperability between applications
like WAP, HTML, and voice - allowing the end user to simultaneously input
voice command and receive - presentation via WAP or HTML.
49Appendix A Parlay
- Parlay is an evolving set of specifications
for industry-standard application programming
interfaces (APIs) for managing network "edge"
services - call control
- messaging
- content-based charging.
- Parlay specifications are being developed by
the Parlay Group, a consortium of member
companies that include ATT, BT, Cisco, IBM,
Lucent, Microsoft, Nortel Networks, and others. - Use of the Parlay specifications is expected
to make it easier to add new cross-platform
network applications so that users need not
depend solely on the proprietary offerings of
carriers. - The Parlay Group is not a standards group
itself, but sees itself as a facilitator of
needed interfaces. Application program interfaces
are or will be defined for
50Parlay
- Authentication
- Integrity management
- Operations, administration, and maintenance
(OAM) - Discovery (of the closest provider of a service)
- Network control
- Mobility
- Performance management
- Audit capabilities
- Generic charging and billing
- Policy management
- Mobile M-commerce/E-commerce
- Subscriber data/user profile/virtual home
environment (VHE) - The Parlay APIs are said to complement and
encourage use of the Advanced Intelligent Network
(AIN) protocols.
51Appendix B Application level protocols
- A. LDAP (Lightweight Directory Access Protocol)
- LDAP (Lightweight Directory Access Protocol) is a
software protocol for enabling anyone to locate
organizations, individuals, and other resources
such as files and devices in a network, whether
on the public Internet or on a corporate
Intranet. - LDAP is a "lightweight" (smaller amount of code)
version of Directory Access Protocol (DAP), which
is part of X.500, a standard for directory
services in a network. LDAP is lighter because in
its initial version it did not include security
features. - LDAP originated at the University of Michigan and
has been endorsed by at least 40 companies.
Netscape includes it in its latest Communicator
suite of products. Microsoft includes it as part
of what it calls Active Directory in a number of
products including Outlook Express. Novell's
NetWare Directory Services interoperates with
LDAP. Cisco also supports it in its networking
products.
52B. LDAP
- In a network, a directory tells you where in the
network something is located. On TCP/IP networks
(including the Internet), the domain name system
(DNS) is the directory system used to relate the
domain name to a specific network address (a
unique location on the network). However, you may
not know the domain name. LDAP allows you to
search for an individual without knowing where
they're located (although additional information
will help with the search). - An LDAP directory is organized in a simple "tree"
hierarchy consisting - of the following levels
- The root directory (the starting place or the
source of the tree), which branches out to - Countries, each of which branches out to
- Organizations, which branch out to
- Organizational units (divisions, departments,
and so forth), which branches out to (includes an
entry for) Individuals (which includes people,
files, and shared resources such as printers) - An LDAP directory can be distributed among many
servers. Each server can have a replicated
version of the total directory that is
synchronized periodically. An LDAP server is
called a Directory System Agent (DSA). An LDAP
server that receives a request from a user takes
responsibility for the request, passing it to
other DSAs as necessary, but ensuring a single
coordinated response for the user.
53B. Authentication, Authorization, Accounting
(AAA)
- Authentication, Authorization, Accounting (AAA)
is a term for a framework for intelligently
controlling access to computer resources,
enforcing policies, auditing usage, and providing
the information necessary to bill for services.
These combined processes are considered important
for effective network management and security. - As the first process, authentication provides a
way of identifying a user, typically by having
the user enter a valid user name and valid
password before access is granted. The process of
authentication is based on each user having a
unique set of criteria for gaining access. The
AAA server compares a user's authentication
credentials with other user credentials stored in
a database. If the credentials match, the user is
granted access to the network. If the credentials
are at variance, authentication fails and network
access is denied. - Following authentication, a user must gain
authorization for doing certain tasks. After
logging into a system, for instance, the user may
try to issue commands. The authorization process
determines whether the user has the authority to
issue such commands. Simply put, authorization is
the process of enforcing policies determining
what types or qualities of activities, resources,
or services a user is permitted. Usually,
authorization occurs within the context of
authentication. Once you have authenticated a
user, they may be authorized for different types
of access or activity. -
54B. Authentication, Authorization, Accounting (AAA)
- The final term in the AAA framework is
accounting, which measures the resources a user
consumes during access. This can include the
amount of system time or the amount of data a
user has sent and/or received during a session.
Accounting is carried out by logging of session
statistics and usage information and is used for
authorization control, billing, trend analysis,
resource utilization, and capacity planning
activities. - Authentication, authorization, and accounting
services are often provided by a dedicated AAA
server, a program that performs these functions.
A current standard by which network access
servers interface with the AAA server is the
Remote Authentication Dial-In User Service
(RADIUS).
55C. RADIUS
- Remote Authentication Dial-In User Service
(RADIUS) is a client/server protocol and software
that enables remote access servers to communicate
with a central server to authenticate dial-in
users and authorize their access to the requested
system or service. RADIUS allows a company to
maintain user profiles in a central database that
all remote servers can share. It provides better
security, allowing a company to set up a policy
that can be applied at a single administered
network point. Having a central service also
means that it's easier to track usage for billing
and for keeping network statistics. Created by
Livingston (now owned by Lucent), RADIUS is a de
facto industry standard used by a number of
network product companies and is a proposed IETF
standard.
56Appendix C. Additional NGN signaling protocols
57A. SIP-T
- SIP-T (SIP for telephones) is a mechanism that
uses SIP to facilitate the interconnection of the
PSTN with IP. SIP-T defines SIP functions that
map to ISUP interconnection requirements. - This is intended to allow traditional IN-type
services to be seamlessly handled in the Internet
environment. It is essential that SS7 information
be available at the points of PSTN
interconnection to ensure transparency of
features not otherwise supported in SIP. SS7
information should be available in its entirety
and without any loss to the SIP network across
the PSTN-IP interface.
58B. SIGTRAN
- SIGTRAN (for Signaling Transport) is the standard
Telephony Protocol used to transport Signaling
System 7 signals over the Internet. SS7 signals
consist of special commands for handling a
telephone call. - The IETF Signaling Transport working group has
developed SIGTRAN to address the transport of
packet-based PSTN signaling over IP Networks,
taking into account functional and performance
requirements of the PSTN signaling. For
interworking with PSTN, IP networks will need to
transport signaling such as Q.931 or SS7 ISUP
messages between IP nodes such as a Signaling
Gateway and Media Gateway Controller or Media
Gateway. Applications of SIGTRAN include Internet
dial-up remote access and IP telephony
interworking with PSTN.
59B. SIGTRAN
- A telephone company switch transmits SS7 signals
to a SG. The gateway, - in turn, converts the signals into SIGTRAN
packets for transmission over IP - to either the next signaling gateway.
-
- The SIGTRAN protocol is actually made up of
several components (this is - what is sometimes referred to as a protocol
stack) - standard IP
- common signaling transport protocol (used to
ensure that the data required for signaling is
delivered properly), such as the Streaming
Control Transport Protocol (SCTP) - adaptation protocol that supports "primitives"
that are required by another protocols.
60C. Bearer Independent Call Control (BICC)
- Bearer Independent Call Control (BICC) is a
signaling protocol based on N-ISUP that is used
to support NB-ISDN service over a BB backbone
network without interfering with interfaces to
the existing network and end-to-end services.
Specified by the ITU-T in recommendation Q.1901,
BICC was designed to be fully compatible with
existing networks and any system capable of
carrying voice messages. BICC supports narrowband
ISDN services independently of bearer and
signaling message transport technology.
61C. Bearer Independent Call Control (Cntd.)
- ISUP messages carry both call control and
bearer control information, identifying the
physical bearer circuit by a Circuit
Identification Code (CIC). However, CIC is
specific to time-division multiplexed TDM
networks. BICC was developed to be interoperable
with any type of bearer, such as those based on
asynchronous transfer mode ATM and IP
technologies, as well as TDM. - BICC separates call control and bearer
connection control, transporting BICC signaling
independently of bearer control signaling. The
actual bearer transport used is transparent to
the BICC signaling protocol - BICC has no
knowledge of the specific bearer technology.
62C. Bearer Independent Call Control (Cntd.)
- The ITU announced the completion of the second
set of BICC protocols (BICC Capability Set 2, or
CS 2) in July 2001 these are expected to help
move networks from the current model - which is
based on public-switching systems - to a
server-based model. The BICC deployment
architecture comprises a proxy server and a media
gateway to support the current services over
networks based on circuit-switched, ATM, and IP
technologies, including third-generation
wireless. - The completion of the BICC protocols is an real
and important ITU step toward broadband
multimedia networks, because it will enable the
seamless of circuit-switched TDM networks to
high-capacity broadband multimedia networks. The
3GPP has included BICC CS 2 in the UMTS release
4. Among the future ITU-T plans for BICC are the
inclusion of more advanced service support and
more utilization of proxies, such as the SIP
proxy.