ngn standardization lms

NEXT GENERATION

NETWORKS

STANARDIZATION

Dr. Omayma Abdel Mohsen

Switching Department

National Telecommunication Institute (NTI)

Content

• Introduction

• ITU NGN Standardization

• ETSI NGN Standardization

Introduction

• The NGN standardization work started in 2003

within ITU-T, and is worldwide today in various

major telecom standardization bodies.

• The most active NGN relevant standardization

bodies are ITU, ETSI, ATIS, CJK and TMF.

• The Next Generation Mobile Networks (NGMN)

initiative is a major body for mobile specific NGN

activities, which are also becoming important

contributors to the 3GPP specification for NGMN.

By end of 2005, ITU and ETSI had published the

NGN specification Release 1:

• ITU NGN R1 defined the framework of NGN and

was conceptual and not implementable.

• ETSI NGN R1 was targeted at implementable

specifications, although focusing on VoIP and

xDSL access.

ITU NGN STANDARDS

NGN functional architecture

Transport stratum

Service stratum

Control

Media

Managem

ent

Funct

ions

Management

ANI

Transport Control Functions

Resource and Admission

Control Functions

Network AttachmentControl Functions

NNIUNI

Application Support Functions & Service Support Functions

Third Party Applications

Transport Functions

End-User

Functions Other

Networks

Service Control

Functions

Service UserProfiles

Transport User Profiles

The solid lines indicate the user traffic; the dashed lines indicate the signalling paths;

the thick dashed lines indicate the management data flows.


The functional architecture is composed of functional

groups separated by well defined interfaces.

Each functional group contains a set of functional entities.

The main functional groups are

– the transport stratum,

– the service stratum,

– the end-user functions,

– the third-party applications,

– the management functions and

– the other networks.


The main interfaces are

• the UNI between the user and network interfaces,

• the ANI between the application and network

interfaces and

• the NNI between the network and network interface.

Component view of a possible realization of

NGN functional architecture.

LegacyTerminals

Note: Gateway (GW) may exist in either Transport Stratum or End-User

Functions.

*

LegacyTerminals

Transport Stratum

Service Stratum

End-User

Functions

Application Functions

Core transport

FunctionsNGNTerminals

CustomerNetworks

Oth

er N

etw

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s

Application Support Functions and

Service Support Functions

Core Transport

Functions

Oth

er N

etw

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s

Edge

Functions

Access Transport

Functions

Service

Control

Functions

Network Access

Attachment Functions

Network Attachment

Control Functions

(NACF)

Access Network

Functions


Control Functions

(RACF)

UserProfile

Functions

T. User

Profile

Functions

GWGW

Other NGN Service

Components

PSTN/ISDN Emulation

Service Component

IP Multimedia Component

&PSTN/ISDN Simulation

IP Multimedia

Service Component

S. User

Profile

Functions

GWGW

Applications

Broadband access able

to provide IPTV

Re-use and

adaptation of

3GPP IMS to

provide

multimedia

services

A unified IP network

with improved security

and QoS

A variety of

mobile and fixed

terminals and

their profile

management

targeting at FMC

Service delivery

platform making use of

NGN easily

Evolution

scenario of PSTN

and short-term

solution

Border gateways

enabling secure

interworking

Media processing to

assist content delivery

Transport Stratum Functions

The transport stratum functions include

transport functions,

transport control functions and

transport user profiles.

Transport functions

Provide the connectivity for all components and physicallyseparated functions within the NGN.

These functions provide support for the transfer of media

information, as well as the transfer of control and

management information.

Transport functions include

– access transport functions,

– edge functions,

– core transport functions and

– gateway functions.

– Resource and Admission Control functions

– Network Attachment Control Functions

Transport Function: Access transport

Function• The access transport functions take care of end-users’

access to the network as well as collecting and

aggregating the traffic coming from these accesses

towards the core network.

These functions also perform QoS control mechanisms

dealing directly with user traffic, including buffer

management, queuing and scheduling, packet filtering,

traffic classification, marking, policing and shaping

These functions also include access-technology dependent

functions, e.g. the WCDMA mobile access and the xDSL

fixed access. Depending on the technology used for

accessing NGN services, the access network includes

functions related to optical access, cable access, xDSL

access, wireless access, e.g. IEEE 802.11 and 802.16

access technologies, and IMT2000 radio access

technologies.

The following is a non-exhaustive list of candidate

technologies to implement

access transport functions for NGN Release 1.

Wireline access:

• xDSL – this includes ADSL, SHDSL and VDSL transport systems

and supporting connection/multiplexing technologies;

• SDH dedicated bandwidth access;

• optical access – this covers point-to-point and xPON transport

systems such as BPON, GPON and EPON (Gigabit EPON is

sometimes called GEPON).

• cable networks – this covers cable networks based on packet cable

multimedia specifications.

• LANs – this covers LANs using either coaxial or twisted pair cable,

including 10Base-T ethernet, fast ethernet, gigabit ethernet and 10

gigabit ethernet;

• PLC networks – the PLC network transmits and receives data over

the power line.

The following is a non-exhaustive list of candidate

technologies to implement

access transport functions for NGN Release 1.

Wireless access:

• IEEE 802.11x WLAN;

• IEEE 802.16x WiMAX;

• any 3GPP or 3GPP2 IP-CAN (NGN does not

support the CS domain as an access transport

technology);

• broadcast networks – this covers 3GPP/3GPP2

Internet broadcast/multicast, DVB, and ISDB-T.

Transport Function: Edge

Functions

• The edge functions are used for media and

traffic processing when aggregated traffic

coming from different access networks is

merged into the core transport network;

they include functions related to support for

QoS and traffic control.

• These functions are also used between

core transport networks.

Transport Function: Core

Transport FunctionThe core transport functions are responsible for

ensuring information transport throughout the

core network. These functions provide IP

connectivity, at the transport stratum and across

the core network, and provide the means to

differentiate the quality of transport in the core

network.

They also provide QoS mechanisms dealing

directly with user traffic, including buffer

management, queuing and scheduling, packet

filtering, traffic classification, marking, policing,

shaping, gate control, and firewall capability.

Transport Function: The gateway

Function

Provide capabilities to interwork with end-user

functions and other networks, including other

types of NGN and many existing networks, such

as the PSTN/ISDN and the public Internet.

These functions can be controlled• directly from the service control functions or

• through the transport control functions.

Transport Function: The media

handling functions

Provide media resource processing for service

provision, such as the generation of tone signals

and trans-coding.

These functions are specific to media resource

handling in the transport stratum.

The Transport Control Functions

include resource and admission control functions(RACF) and network attachment control

functions (NACF).

The RACF provides QoS control (including

resource reservation, admission control and gate

control), NAPT and/or FW traversal control

functions over access and core transport

networks.

The Admission control involves checking

authorization based on user profiles, SLAs,

operator-specific policy rules, service priority and

resource availability within access and core

transport.

The Transport User Profile

Functions

take the form of a functional databaserepresenting the combination of a user’s

information and other control data into a

single ‘user profile’ function in the transport

stratum.

This functional database may be specified

and implemented as a set of cooperating

databases with functionalities residing in

any part of the NGN.

Network Attachment in NGN

The network attachment function in NGN provides

mechanism for attaching users to the network

In fixed line access, the user’s CPE can be a fixed

node that allows multiple devices to connect to

the network (e.g., a multi-line modem or router).

The terminals attached to it are therefore known

by their lines or ports on that CPE and, once

installed, can be “implicitly “ authenticated.

In addition, NGN needs to provide for nomadic

users who not only move with their equipment

(e.g., laptops), but also might log in on different

devices, yet receive their own network services.


NGN functional architecture.


Control Functions

RACF

Network Access


NACF

Other Multimedia

Components …

Streaming Services


Core transport

Functions

Access Transport

Functions

NGN Terminals

Customer

Networks

User

Profile

Functions

Oth

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etw

ork

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LegacyTerminals

GW

PSTN / ISDN Emulation


NNITransport Stratum

Service Stratum

UNI

Edge FuntionsAccess

Functions

Service

and

Control

Functions

Customer and

Terminal Funct. QoS Aspects and one part of Control aspect

(IP QoS signaling Requirement)

Release 1 coverage

provide registration at

the access level and

initialization of end-

user functions for

accessing the NGN

services

There are two stages for

network admission1. At the IP CAN level Initial equipment identification and

handshake procedures, and the attachment to the network

with a valid IP address

– The UE provides details of its equipment identifier to the access point,

which then returns an IP address. This IP address can be obtained

from a local DHCP server.

– Once the UE has an address for its first network node to contact, it

requests admission to the network through a validation process.

2. In the second stage, the user identification (for

IMS,PSTN/ISDN Emulation…) is performed and usage of the

services is authorized.

The authentication can be mutual, where the network node

must be recognized by the UE and the UE must be identified

by the network.

Types of IP CAN bearer network: xDSL, WLAN and UMTS.

The UE in NGN connects via a static node or CPE,

such as residential modems or gateways or IADs

(Integrated Access Devices).

The addresses of these nodes are generally

known to the network by preconfiguration or are

registered at installation time.

Nomadic users become attached dynamically to

these gateways, obtaining their temporary IP

address from preconfigured lists or via a network

DHCP server.

The NACF provides the

following functionalities

• Dynamic provisioning of IP addresses and other CPE

configuration parameters.

• By endorsement of user, auto-discovery of CPE

capabilities and other parameters.

• Authentication of end user and network at the IP layer

(and possibly other layers).

• Regarding the authentication, mutual authentication

between end user and the network attachment is

performed.

• Authorization of network access, based on user profiles.

• Access network configuration, based on user profiles.

• Location management at the IP layer.

Access network level

registration

NACF registration involves the identification, authentication,

and authorization procedures between the CPE and the

NACF to control the access to the NACF.

Two authentication types are defined for NACF

Implicit authentication: It may be performed by the NACF

based on the line identification of the connection to the

CPE

Explicit authentication: It is operating between the CPE and

the NACF. It requires a signalling procedure to be

performed between the CPE and the NACF.

NACF has interaction with the

following NGN components • Service control functions (SCF) (e.g., such as

those of the IMS service component for exporting

information on access sessions)

• Resource and admission control functions

(RACF) for exporting transport subscription

profile information;

• Transport functions (i.e., access relay functional

entity (AR-FE) acting as relays to/from the CPE

for address allocation, authentication and

authorization purposes

• The customer premises equipment (CPE) at the

for configuration purposes.


GSI-NGN functional architecture.


Control Functions

RACF

Network Access


NACF

Other Multimedia

Components …

Streaming Services


Core transport

Functions

Access Transport

Functions

NGN Terminals

Customer

Networks

User

Profile

Functions

Oth

er N

etw

ork

s

LegacyTerminals

GW

PSTN / ISDN Emulation


NNITransport Stratum

Service Stratum

UNI

Edge FuntionsAccess

Functions

Service

and

Control

Functions

Customer and

Terminal Funct. QoS Aspects and one part of Control aspect

(IP QoS signaling Requirement)

Release 1 coverage


Control Function (RACF)

The transport control function serves as an

arbitrator connecting the service stratum and the

transport stratum.

It determines the admission of the service request

based on the network resource state and the

policy of the network provider.

It also controls the network equipment to allocate

the actual resources in the network.

The RACF is the function that determines the

availability of the resources and appropriately

controls the network element.

RACF

• The RACF provides an abstract view of transport network

infrastructure to the SCF and makes service providers

agnostic to the details of transport facilities such as

network topology, connectivity, resource utilization and

QoS mechanisms/technology, etc.

• The RACF interacts with the Service Control Function

(SCF) and transport functions for a variety of applications

(e.g., SIP-based call , video streaming, etc.) that require

the control of NGN transport resources, including QoS

control, NAPT/firewall control and NAT traversal.

RACF within the NGN architecture

(1/Y.2111)

RACF is positioned exactly on the border as the arbitrator of the service and

transport strata.

RACF

• The RACF executes policy-based transport resource

control upon the request of the SCF, determines

transport resource availability, makes admission

decisions, and applies controls to transport functions for

enforcing the policy decisions.

• The RACF interacts with transport functions for the

purpose of controlling one or more of the following

functions in the transport stratum:• bandwidth reservation and allocation,

• packet filtering;

• traffic classification,

• marking,

• policing, and priority handling;

• network address and port translation;

• firewall.

RACF

• The RACF interact with NACF, including network access

registration, authentication and authorization, parameters

configuration, to check user profiles and Service Level

Agreement (SLA) held by them.

Generic Resource and

Admission Architecture in NGN

RACF Logical Entities

• Policy Decision Functional Entity (PD-FE),

• Transport Resource Control Functional entity (TRC-FE),

and

• Policy Enforcement Functional Entity (PE-FE).

Rw

Service Stratum

Transport Functions

Policy

Decision

Function

Transport Resource ControlFunction RACF

Transport Stratum

Service Control Functions

Rn

Oth

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GN

s

Transport

Enforcement

Function

Policy

Enforcement

Function

Network Attachment

Control Functions

intra-domain

inter-domain


• The PD-FE is the northbound interface to the service control

functions (SCF) i.e., application functions such as video

headend, is an inter-provider interface.

• Thus, an application provider that does not own a network

infrastructure can use this interface to request resources from

the network provider.

• The PD-FE performs resource authorization and media

reservations including gate control, QoS and priority handling,

selection of the firewall working mode, and NAPT commands.

• The PD-FE in the access network interacts with the NACF to

obtain the transport subscription information, and binding

information between the physical and IP addresses


• The TRC-FE monitors the status of resources and collects the

relevant network information. Based on this information, it

performs resource-based admission control.

• In general, the role of the TRC-FE is to monitor network

utilization and to use this knowledge for flow admission.

• The last functional entity that remains is the policy enforcement

functional entity (PE-FE), which enforces the network operator’s

policy on both a per-flow and per-subscriber basis.

• The PE-FE opens and closes the gates, limits the packet rate,

and performs traffic classification, packet marking, NAPT, NAT

traversal, and usage metering. It also maps the network-layer

QoS information into that of the link layer.

The service stratum functions

Includes

the service control functions

the application/service support functions, service

user profile functions.

The service control functions include both session

and non-session control, registration and

authentication and authorization functions at the

service level.

They can also include functions for controlling

media resources, i.e. specialized resources and

gateways at the service-signalling level.


Within the service control functions, the possible

components included are

the IP multimedia component,

the PSTN/ISDN emulation component,

the streaming services component and

other multimedia components


The service user profile functions represent thecombination of user information and other control

data into a single user profile function in the

service stratum, in the form of a functional

database.

This functional database may be specified and

implemented as a set of cooperating databases

with functionalities residing in any part of the

NGN.

TELECOMMUNICATIONS AND INTERNET

CONVERGED SERVICES AND

PROTOCOLS FOR ADVANCED

NETWORKING (TISPAN)

The TISPAN-NGN is targeted at

Providing NGN services

• conversation (voice call, video call, chat, multimedia

sessions);

• messaging (email, SMS, EMS, MMS, instant messaging

and presence);

• content-on-demand (browsing, download, streaming,

push, broadcast).

Supporting Access Technologies

• 3GPP standardized mobile

GSM/GPRS/EDGE/UMTS/HSPA/LTE;

• fixed DSL;

• wired LAN;

• wireless LAN;

• cable

TISPAN NGN

• The TISPAN NGN specification covers NGN services,

architectures, protocols, QoS, security and mobility

aspects within fixed networks.

• TISPAN and 3GPP was working together to define a

harmonized IMS-centred core for both wireless and

wireline networks. This harmonized all-IP network has

the potential to provide a completely new telecom

business model for both fixed and mobile network

operators.

• Access-independent IMS is a key enabler for fixed/mobile

convergence, reducing network installation and

maintenance costs, and allowing new services to be

rapidly developed and deployed to satisfy new market

demands.

TISPAN NGN overall

Architecture

This NGN functional architecture described complies with the ITU-T general

reference model for next-generation networks and is structured according to

a service layer and an IP-based transport layer.

The service layer comprises the following components:

• The core IP Multimedia Subsystem (IMS); this component

supports the provision of SIP based multimedia services to

NGN terminals and also supports the provision of

PSTN/ISDN simulation services;

• PSTN/ISDN emulation subsystem (PES) – this component

supports the emulation of PSTN/ISDN services for legacy

terminals connected to the NGN, through residential

gateways or access gateways;

• streaming subsystem – this component supports the

provision of RTSP-based streaming services to NGN

terminals;

• Content broadcasting subsystem – this component supports

the broadcasting of multimedia content (e.g. movies,

television channels etc.) to groups of NGN terminals;

The Transport Layer

The transport layer comprises

a transport control sub-layer on top of transfer functions.

The transport control sub-layer is further divided in twosubsystems, i.e.– the network attachment subsystem (NASS) and

– the resource and admission control subsystem (RACS).

Transport Control Sub-layer

IP-connectivity is provided to NGN user

equipment by the transport layer, under the

control of the Network Attachment

SubSystem (NASS) and the Resource and

Admission Control Subsystem (RACS).

These subsystems hide the transport

technology used in access and core

networks below the IP layer.

Network Admission Subsystem

(NASS)

TISPAN has defined network admission vision for

NGN, which is a Fixed/Mobile converged

network model particularly suitable for nomadic

users who can move not only between locations,

but also to any terminal (e.g., PC).

In TISPAN NGN, the NASS (Network Attachment

Subsystem)is designed to allow a variety of NGN

access forms: xDSL, cable, WLAN, Ethernet,

and Enterprise VPN.

In WLANs, the air interface process of admission is

managed by the WLAN access point and

gateways.

Network attachment Subsystem

(NASS) functionality:• Dynamic provision of IP address and other user

equipment configuration parameters (e.g. using

DHCP).

• User authentication, prior or during the IP address

allocation procedure.

• Authorization of network access based on user

network profile (e.g. subscribed bandwidth

capacity).

• Access network configuration (default firewall

setting), based on user profile.

• Location management (e.g. for emergency call,..).

• CPE configuration


Control Subsystem (RACS)

• RACS provides admission control and gate control

functionalities including the control of NAPT and priority

making.

• Admission control involves checking authorization based

on user profiles held in the access network attachment

subsystem, on operator-specific policy rules and on

resource availability.

• Checking resource availability implies that the admission

control function verifies whether the requested bandwidth

is compatible with both the subscribed bandwidth and the

amount of bandwidth already used by the same user on

the same access, and possibly other users sharing the

same resources.

The transfer functions and their

relationship with the other components

Only the functional entities that may interact with the

transport control sub-layer or the service layer are visible

in the transfer sub layer.

These are:

• The media gateway function (MGF). The MGF provides the media

mapping between an IP-transport domain and switched circuit

network facilities (trunks, loops). It may also perform media

conferencing and send tones and announcements;

The transfer functions and their relationship with the other components• The border gateway function (BGF) provides the interface

between two IP transport domains.

It may reside– at the boundary between an access network and the customer terminal

equipment,

– between an access network and a core network or

– between two core networks.

The transfer functions and their relationship with the other components

The access relay function (ARF) acts as a relay between the user

equipment and the NASS.

It receives network access requests from the user equipment and

forwards them to the NASS.

Before forwarding a request, the ARF may also insert local configuration

information and apply protocol conversion procedures.

The transfer functions and their relationship with the other components

• The signalling gateway function (SGF) performs signalling

conversion (both ways) at the transport level between the

SS7-based transport of signaling and IP-based signalling

transport.

The transfer functions and their relationship with the other components• The media resource function processor (MRFP) provides

specialized resource processing functions beyond those

available in media gateway functions. This includes

resources for supporting multimedia conferences,

sourcing multimedia announcements, implementing IVR

(interactive voice response) capabilities and media

content analysis.

Possible realization of the TISPAN NGN

functional architecture, with an xDSL-

based access network.

The TISPAN NGN configuration

with xDSL assumes the following:• A Core-Border Gateway Function (C-BGF) is implemented

in a Core Border Node sitting at the boundary between

the access network and a core network, at the core

network side.

• A Resource Control and Enforcement Function (RCEF) is

implemented in an IP Edge node sitting at the boundary

between core networks, at the access network side. In

this example, this node also implements the ARF

functional entity.

• A Interconnection Border Gateway Function (I-BGF) is

implemented in a Border GateWay (BGW) sitting at the

boundary with other IP networks.

The TISPAN NGN configuration

with xDSL assumes the following:

• A Trunking Media Gateway Function (T-MGF) is

implemented in a Trunking GateWay (TGW) at the

boundary between the core network and the PSTN/ISDN.

• A Access Media Gateway Function (A-MGF) is

implemented in an Access Node (AN) which also

implements a DSLAM.

• A Residential Media Gateway Function (R-MGF) is

implemented in a Residential GateWay (RGW) located in

the customer premises.

Questions

1. The NGN functional architecture is composed of functional

groups separated by well defined interfaces, Discuss.

2. State the NGN Transport control Functions and discuss their

functionality.

3. Discuss the Network Attachment Control Function (NACF)

functionality and its interaction with different NGN

Components.

4. Discuss the functionality of the Resource and Admission

Control Function (RACF)

5. State the possible components of the service control

functions.

6. In TISPAN-NGN transfer functions state two Functional

Entities and describe their relation with other NGN

components

ngn standardization lms

Documents

itu ngn r1

etsi ngn r1

ngn standardization

enduser functions

ngn specification release

network interfaces

main functional groups

set of functional entities