Draft National Broadband Network Reference Architecture Oct 2009

8/8/2019 Draft National Broadband Network Reference Architecture Oct 2009

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Draft - Version 1.9 14 Oc tober 2009 For Discussion Only

COMMUNICATIONS

ALLIANCE LTD

NATIONAL BROADBAND NETWORK

REFERENCE ARCHITECTURE

HIGH LEVEL ARCHITECTURE OPTIONS FOR THE NBN

DRAFT FOR COMMENT

OCTOBER 2009



DRAFT National Broa db and Network Referenc e Arc hitec tureHigh Leve l Architec ture Op tions for the NBN pa per

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DRAFT NBN REFERENCE ARCHITECTURE OCTOBER 2009

HIGH LEVEL ARCHITECTURE OPTIONS FOR THE NBN COPYRIGHT



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TABLE OF CONTENTS

1 PURPOSE AND SCOPE 2 2 BROADBAND NETWORK ARCHITECTURE VISION 3 3 BROADBAND NETWORK REFERENCE ARCHITECTURE – FTTP ACCESS 4

3.1 Key Network Doma ins and Func tions 4 3.2 Wholesale Point of Interconnec t and Service Boundary Point Scena rios

8 3.3 Roles and Rela tionships between Different Industry Players 10 3.4 Rela tionship be tween CPE and Reta il/Wholesale providers 12

4 BROADBAND NETWORK REFERENCE ARCHITECTURE – WIRELESS/ SATELLITE

ACCESS 14 4.1 Option 1: Laye r 2 Ethernet Ac cess 14 4.2 Option 2: Wireless/ Satellite Layer 3 IP Ac cess 18

5 FURTHER CONSIDERATIONS 22 5.1 Sustainability 22 5.2 Robustness 22 5.3 Security 22 5.4 IPv6 22 5.5 Future Proo fness 22

6 ABBREVIATIONS 23

Any o utp uts from the Comm unica tions Allianc e NBN Projec t inc luding o n the NBN WIKIand in this do cument do not rep resent preferred Com munica tions Allianc e, industry or

individua l Comm unica tions Allianc e me mb er positions. The outputs in this doc umentrep resent a rang e of scena rios and op tions that the Com munica tions Allianc e wo rking

groups have identified with the purpose of facilitating broader discussion and decision

ma king o n the NBN.

While the scena rios p resented in this pap er are tec hnica lly fea sible, any agreed set o fscena rios will req uire trad eoffs be tween tec hnical a nd op erational comp lexity verses

req uirements for ma ximum flexibility in supp ort o f func tiona l and service req uirements.

These issues will need further a na lyses as part of more deta iled Comm unica tions Alliance

wo rk stream ac tivities.





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1 PURPOSE AND SCOPE

This doc ume nt has been end orsed by the NBN Referenc e Mo del working g roup

charged with developing a set of high level NBN network architec ture o ptions.

These inputs have b een de velop ed to a ssist the Comm unica tions Allianc e inesta blishing an industry ag reed set of NBN refe renc e a rc hitec ture op tions.

This doc ume nt d efines the following:

• The end -to-end broad ba nd ne two rk architecture framew ork, inc luding

do ma ins and funct ions req uired to de liver a wide rang e o f netw ork servic es

and ap plicat ion/ content services to e nd users.

• A range of potential passive and active NBN wholesale interconnect scenarios.

This will be a key input to other Comm unica tions Allianc e NBN work stream

activities, in p articula r the who lesa le services stream . In deve loping these

options there has been some regard to overseas experience where different

FTTH who lesa le op en a cc ess mo dels a re b eing a dop ted by d ifferent c ountries.

• Terminology a nd definitions for different industry players taking into a ccount a

rang e o f possible roles p roviding Wholesa le and Reta il services.

• The rela tionship b etween the CPE (suc h as ONT and RG) a nd Reta il and

Wholesa le Service Providers.





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2 BROADBAND NETWORK ARCHITECTURE VISION

The next-generation b roa db and netwo rk will enable a wide range of netw ork

services and app lica tion/ content services to be d elivered to end users via FTTP,

Wireless and Sate llite acc ess. Figure 1 show s the end-to-end architec ture visionwhich identifies the d ifferent func tional and service d oma ins ap plicab le to the

provision of Next Ge neration Broadband Services. The reta il netwo rk service

provide rs and ap plic ation/ content service p roviders are those tha t p rovide services

to e nd users and have a d irec t c ustomer relat ionship with the end users. Wholesa leservice provide rs do not have this relat ionship.

Figure 1Broadband Network Architecture Vision





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3 BROADBAND NETWORK REFERENCE ARCHITECTURE – FTTP

ACCESS

The prima ry form of a ccess to the NBN will be Fibre to the Premises (FTTP). This

sec tion d esc ribes the end -to-end netwo rk a rchitec ture fo r FTTP ac cess.

Figure 2 shows the end -to-end b roa db and netwo rk reference a rc hitec ture,

seg reg ated into a numb er of func tiona l dom ains. This architec ture is based on the

reference architec ture d efined by the Broa db and Forum1 but has been ad aptedfor the spe c ific p urposes of this exercise. In particular, the te rminology used in this

do cume nt is not fully aligne d w ith tha t used by the Broa dba nd Forum. It should b enoted that the terminology used in this do cument w ill be reviewed and ma y

change in future releases.

Figure 2

Broad ba nd Network Reference Architec ture - FTTP Ac cess

3.1 Key Network Domains and Func tions

The fo llow ing sec tions desc ribe the key netw ork func tions in eac h of the netw ork

domains.

3.1.1 End User Dom ain

End users will be loc a ted in residentia l and non-residentia l p rem ises and a lso in

non-premises based locat ions suc h as pub lic roa d infrastructure (traffic cont rol

systems, stree t lights, surveillanc e c ame ras, etc .).

The key func tions req uired in the end user do ma in are:

1

International forum for deve loping b roa db and netwo rk spe c ifica tions.See www.broadband-forum.org



http://www.broadband-forum.org/

http://www.broadband-forum.org/



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• Optical Network Termina tion (ONT)/ Network Termina tion Unit (NTU) devices

which terminate the op tic al network and provide a range o f end user

interfaces. This device could be loc a ted indoors or outdo ors.

• Routing Gateways (RG) which p rovide a laye r 3 (IP) ga teway func tion between

end d evices and the netwo rk. They inc lude func tions for:IP rout ing, IP ad dress allocat ion to end devices, QoS, Network Add ress

Translat ion (NAT), firewa ll, ma nagem ent, Domain Name Server (DNS) and

network authentication.

A Reta il NSP ma y inc lude a dd itiona l capab ilities on the RG not listed a bove .

• Premises (Hom e) Networks which p rovide c onnec tivity betwee n RGs and end

devices.

• End d evices which can be app licat ion spec ific (e.g. Set Top Boxes, Phone s) or

can be more general in nature (e.g. Personal Computers).

It should be noted that some end de vices do not necessarily need a RG func tion

and can b e c onnec ted direc tly to the ONT.

It should a lso be noted that there a re multiple a rchitec ture op tions to supp ort

multiple service p rovide rs delivering services to the premises and wha t o p tions a re

ap plied will dete rmine the ove rall level of technical comp lexity. This do cument

do es not show a ll of the p ossible a rchitec ture op tions. The w holesa le RG show n in

Figure 2 rep resents only one o f the end user a rc hitec ture op tions.

3.1.2 Ac cess Doma in

The func tion of the Acc ess Doma in is to p rovide conne c tivity from the end user

premises to the ne twork. The Ac cess Domain consists of b oth p assive a nd a c tive

components.

• The p assive com ponents include Op tica l Fibre, Op tica l Sp litte rs, Optica l

Distribution Frames (ODF) and p it and p ipe enc losures.

• The a c tive compone nts include Op tica l Network Termination (ONT) and

Op tica l Line Termina tion (OLT) eq uipm ent .

• Ethernet Aggreg at ion Switc hes (EAS) which agg reg ate multiple OLTs at a loca l

excha nge site.

3.1.3 Aggregation & Transport Domain

The funct ion of the ag grega tion and transpo rt do ma in is to a gg regate a largenumber of a ccess connec tions onto a relatively sma ll number of physical interfac es

and transport these connections from local, distributed locations to centralised

locations such as major regional and metropolitan centres with regional, state or

national scope.

Multiple leve ls of a gg reg ation a re p ossible (e.g. loc a l, reg ional, sta te , nationa l) with

po tential for multiple service p roviders to o pe rate in this dom ain. It should b e

note d tha t service p rovide rs ma y po tent ially provide transpo rt-only services without

any agg rega tion.

The c urrent a nd future trend for providing aggregat ion and transport networks is to

use Ethernet based a gg reg ation and t ransport tec hnolog y. As show n in Figure 2,

Ethernet Ag gregat ion Switc hes (EAS) provide the ag gregat ion func tion.





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3.1.4 Service Edge & Core Domain

The main func tion of this dom ain is to p rovide layer 3 (IP) conne c tivity between endde vices, ap plicat ion/ content services and the public Internet. It can a lso p rovide

layer 2 Ethernet VPN and / or layer 3 IP VPN connec tivity betw een end de vice s,

ap plication/ content services and the public Internet.

In the c ase o f providing broad ba nd IP services, there a re tw o m ain ap proac hes for

de livering end user log ica l co nnec tions into the IP servic e laye r:

The p red ominant ap proac h in use to da y involves ag grega tion of Point-to-po intProtoc ol (PPP) end user c onnec tions into Layer 2 Tunne lling Protocol (L2TP) tunne ls

for delivery into the IP netwo rk service layer. While this app roa ch is adeq uate fo r

providing b est effo rt services, the em ergence o f IP based app lica tions req uiringmore stringe nt Qua lity of Service (QoS) has lead to the deve lopm ent o f an

alternative “Q oS ena bled b roa db and ” a pp roa ch. This alternat ive ap proac hena b les the provision of end-to-end QoS capab ilities a t the IP service laye r by

providing d irec t Ethernet c onnec tivity between the Routing Ga teway (RG) a t theend user premises and the Broa dband Netwo rk Gateway (BNG) within the IP

service layer.

The key func tions of the BNG a re:

• Prov ide the first p oint o f IP routing for end user traffic

• Enforce subsc riber level Qua lity o f Service (QoS) a nd po lic y d ec isions

• Allow IP multica st rep licat ion

The key func tions of the BNG c ont rol plane are:

• Authe ntica tion o f RGs and assoc iation o f RGs with subsc ribed service p rofiles

• IP Address allocation to RGs

• Manag eme nt of QoS po lic ies on the BNG and the RG

It is generally ac cep ted that QoS enabled broad ba nd is likely to be the d ominant

approa ch in the future, however, given the la rge insta lled base o f L2TP based

services, it is likely tha t both a pproa ches will need to b e supported in the p rop osed

NBN timeframe .

Within the Service Edg e and Core d omain, there are a number of d ifferent

wholesale a nd reta il roles tha t c an be de fined :

• Retail Broadband NSP

• Wholesale L2TP Netw ork Service Provider (NSP)

• Wholesale IP NSP

• Retail L2/ L3 VPN NSP

These roles a re further de fined in sec tion 3.3.





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3.1.5 App lication & Content Doma in

This dom ain provides applica tion and content services to end users such as web-ba sed applica tion content , IP Telep hony, IP Video , Sma rt me tering , ed ucation,

health, etc .

Tod ay, the predo minant mea ns of connec tivity betwee n this do ma in and end

users is via the pub lic Internet (also known as “Over The Top ” ). Othe r connec tivity

models a re p ossible to support ap plica tions req uiring d ifferent c apab ilities to t hose

ava ilab le via the Internet. Examp les inc lude sma rt mete ring o f home a pp lianc es,

de livery of high q ua lity video services, etc . The c onne c tivity op tions listed below

are further defined in sec tion 3.3.

• Over The Top (via p ub lic Internet)

• Connec t via Reta il NSPs

• Connec t via a Broa dband Ac cess Provider (Wholesale Layer 2 Ethernet service)

• Co nnec t via a Wholesa le IP NSP.

Eac h of these connec tivity opt ions are d ifferent and will involve a trad eoff in

tec hnic al and op erational comp lexity b etween the e nd user netwo rk, NSPs and

ASPs.





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3.2 Wholesale Point o f Interconnec t and Service Boundary Point

Scenarios

Within the context of the end -to-end Broa db and Network Reference Architec ture

described in section 3.1, there are a range of p ote ntial Wholesa le Points OfInte rconnec t (POI) and correspond ing Service Bound ary Points (SBP). These POIand SBP scena rios can be de fined by the service func tionality a va ilable a t the

interface, their physical loc at ion and the am ount of ag grega tion they provide.

The possible locat ions within the logica l network hierarchy of the Wholesa le POI

and SBP are shown in Figure 3. They are not intended to rep resent physica l

locations, rather they represent logical points in the network hierarchy which can

be used to further define applica b le service c onstructs. Each POI has a

correspond ing SBP. The numbering o f the POI and SBP scena rios indic a tes the

allow ab le POI and SBP pairings.

The service func tiona lity of ea ch scenario is summarised in Tab le 1 below.

Figure 3

Wholesale Point o f Interconne c t and Servic e Bounda ry Point Scena rios - FTTP Ac cess





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Table 1

Wholesale POI and SBP Scenarios

POI

Scenario

POI Typ e Servic e Func tiona lity POI Physical

Location(s)

SBP Physica l Loc ation(s)

1 Layer 1 -

Passive

Direct

Dark Fibre

Single or m ultiple

direc t (pt-to-pt) da rk

fibres to the e nd user

premises.

• Local Exchange

• Street Ca binet

• Optica l connector

at the:

• Street Pit

(footpath/nature

strip )

• Outdoor Connection

Devic e (OCD)

• Indoor Wall Plate

• Basement ODF

2 Layer 1 -

PassiveDark PON

Single o r multiple dark

PON fibres to the enduser premises

• Local Exchange • Optica l connector

at the:• Street Pit

(footpath/nature

strip )

• Outdoor Connection

Devic e (OCD)

• Indoor Wall Plate

• Basement ODF

3 Layer2 –

Ethernet

Layer 2 Ethernet

service to the end

user p remises.

Servic e c ould b ena tive Ethernet o r

sup port IEEE 802.1q

VLAN interfaces.

Equ ivalent to

Broadband Forum

“ A10 – NSP L2 (Eth)”

interface

3a) Local Exchange

3b) Reg iona l, Sta te or

NationalAgg reg ation POI

• Ethernet p ort on the

end user fac ing side

of the ONT (interna l,

external orbasement)

4 Layer 2 –

Wholesale

L2TP

PPP c onnec tions to

the e nd users

delivered over L2TP

tunnels.

Equ ivalent toBroadband Forum

“ A10 – NSP L2TP”

interface

• Reg iona l, Sta te or

National

Agg reg ation POI

4a ) Ethernet p ort on the


of the ONT (interna l,

external or

basement)4b ) Ethe rnet Port on the


of the RG (PPPoE

pa ss through) 5 Layer 3 -

Wholesale

IP

IP Layer c onne c tivity

to end user devices

Equ ivalent to

Broadband Forum

“ A10 – ASP IP”

interface


National

Agg reg ation POI

• Ethernet p ort on the


of the RG





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3.3 Roles and Rela tionships between Different Industry Players


described in Figure 2, there is scope for a number of different industry roles to exist.

Figure 4 and Table 2 summ arise the d ifferent possible roles and the pote ntial

relat ionships betw een Wholesa le a nd Reta il p rovide rs.

It should b e no ted tha t it is possible for a single p rov ider to p erform m ultip le roles

(reta il and w holesa le). For example, in the case o f who lesale POI scena rios 1 and 2(pa ssive fibre infrastructure) the roles of Broa dband Ac cess Provider, Agg reg ation

Transport Provider and Reta il Broa dba nd NSP could be performe d by a single,integrated who lesa le-reta il service p rovider.

Figure 4

Summa ry of Industry Roles and Wholesale -Reta il Scop e





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Table 2

Industry Roles and Wholesale -Reta il Scope

Provider Role

Passive Fibre

Infrastruc ture

Provider

• Provides passive o ptica l fib re infrastruc ture (inc luding fibre, sp litte rs, ODFs etc .) in a

da rk fibre (pt-p t) and / or da rk Passive Op tica l Netwo rk (PON) co nfiguration from

ea c h end user premises to a Fibre Conc entrat ion Point

Broadband

Access Provider

• Provide s L2 Etherne t services from End Users to Netwo rk Servic e Provid ers or

direc tly to A pp lica tion/C ontent Servic e Providers

• Provid es first level of a gg reg a tion of m ultiple O LTs a t a loc al exc hange site onto a

single p hysica l link to av oid the ne ed to p rovide individua l conne c tions to e ac h

OLT.

• Provid es and op erate s PON O LT and end user ONT

Aggregation

Transpo rt

Provider

• Provid es transport of traffic from loc al Points of Presenc e to c entral loc at ions

• Provides agg reg ation o f end user co nnec tions onto a sma ll numb er of physica l

links

• Multiple providers can fulfil this role

• This role is op tiona l in the sense tha t NSPs c an conne c t d irec tly to the Broa db and

Access Provider

Retail

Broadband

Netw ork Service

Provider

• Provides IP netwo rk c onnec tivity services to end users. e.g .

o Broa db and Internet ac c ess

o Co nnec tivity to A SP/ CSPs

o Authe ntica tion o f RGs and assoc iation of RGs with subsc ribed service profiles

o IP Address allocation to RGs

o Ma nag em ent o f Qo S po licies on the BNG and the RG• There a re many reta il NSPs

Wholesale L2TP

Netw ork Service

Provider

• Ag grega tes End User (PPP) c onnec tions into L2TP tunne ls for d elivery to Netw ork

Servic e Prov ide rs.

• Only supports best effort services

• No IP Ad dressing, RG A uth, Q oS

Wholesale IP

Netw ork Service

Provider

• Provides IP co nnec tivity b etwe en End Users and ASP/ CSPs (IP Ad dressing,

RG Authentica tion, QoS Mg mt)

• Ac ts as a servic e p rovider with nationa l and/ or reg ional sc op e to ena ble simpler

c onnec tivity for ASPs. This avo ids the need for ASPs to c onnec t to multiple NSPs to

reac h the e ntire NBN custom er ba se.Reta il L2/ L3 VPN

Service Prov ide r

• Provides Layer 2 Ethe rnet VPN and / or Layer 3 IP VPN connec tivity services to end

users. A range of va lue ad de d servic es c an a lso b e p rovided . e.g.:

o Firewalled Internet a c c ess

o Hosted application/content services

App lica tion /

Content Service

Provider

(ASP/CSP)

• Provides app lic a tion and c onte nt services to End Users

• 4 op tions to rea c h end users: a) Over The Top (via pub lic Internet); b ) Connec t

via Reta il NSPs; c ) Co nnec t via Broad ba nd Ac c ess Provider (Wholesale Laye r 2

Ethe rnet service); d ) Connec t via a Wholesa le IP NSP.

• Both ASP and CSP are terms used in the industry and a re som et imes used

interchangeably





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3.4 Rela tionship between CPE and Reta il/ Wholesale providers

As desc ribed in sec tion 3.3, a range of d ifferent industry playe rs will provide

wholesa le and reta il services in the NBN environme nt. This sec tion d escribes the

relat ionship betw een the va rious types of CPE req uired to d eliver broadband IP

services and the who lesa le a nd reta il service provide rs of these services.

The relationships summarised in Figure 5 show the d ifferent service layers and howthey ma p to the w holesale a nd reta il service d oma ins.

Figure 5

CPE Servic e Rela tionships

The key rela tionships a re as fo llows:

• Custome r ONT and Network OLT ma nag ed by the sam e p rovider. The layer 2

Ethe rnet service is p rovide d via t he e nd user ONT and network OLT. To e nsure

device c om pa tibility and the integ rity of the service, the ONT and OLT are

tightly coupled and are therefore m ana ged by a single w holesale b roa db and

access provider.

• Eac h Reta il Broad ba nd NSP ma nages their own RG. A reta il broad band NSP willprovide services at layer 3. In order to allow ma nag ement o f authentica tion, IP

addressing and service QoS and bandwidth p rofiles on the RG, a Reta il

Broadband NSP will nee d to mana ge its ow n RG. It is a lso likely that p remises

(home) netwo rk(s) will be setup and ma nag ed by the reta il broa db and NSP(s).

• Wholesale RG m ana ged by a Wholesale IP NSP. Laye r 3 can op tionally inc lude

a who lesa le IP service as desc ribed in sec tion 3.3. For similar reasons to the

Retail NSP case de sc ribed above , the Wholesa le IP service p rovider will need to

ma nage its own RG. This implies tha t there ma y be a req uirement for multiple

RGs at the end user p remises to support b oth Reta il NSP and Wholesa le IP NSP

to deliver services into the p rem ises. The impac ts of supporting m ultiple RGs and

multiple p remises (home) ne tworks at the end user premises or the po tent ial for





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delivering a ll services through a single reta il NSP RG a nd premises (home )

netw ork needs further considerat ion.

• End de vices may or may not be manag ed a s pa rt of the applica tion service.

The a pp lication layer provide s ap plicat ion a nd content servic es to end users

such as voice and video services and web ba sed ap plicat ions and content.The end d evices used to a ccess these services ma y or may no t be p rovided

and mana ged as pa rt of the servic e b eing provided , depe nding o n the

application.





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4 BROADBAND NETWORK REFERENCE ARCHITECTURE –

WIRELESS/ SATELLITE ACCESS

There are two a lterna tive architec tures for p rovid ing broadband services ove r

wireless or sa tellite a ccess, dep end ing on the capa b ilities provide d b y thewireless/ sa te llite access netwo rk.

Currently, wireless and sa tellite netw orks typ ica lly p rovide layer 3 IP connec tivity to

end users. While th is is appropria te fo r p roviding reta il ac cess services, the preferedindustry ap proa ch for wholesale a ccess is to use laye r 2 ac cess connec tivity. This

a lso a ligns with the a pproach for FTTP access. How ever, laye r 2 connec tivitysolutions require development from wireless and satellite vendors.

This sec tion d esc ribes both layer 2 and laye r 3 op tions.

4.1 Option 1: Layer 2 Ethernet Acc ess

The end -to-end netwo rk architec ture c an b e seg regated into a num be r of

func tiona l dom ains as show n in Figure 6.

Figure 6

Network Reference Architec ture – Wireless/ Sate llite Layer 2 Ethernet

4.1.1 Key Network Doma ins and Func tions

The fo llow ing sec tions desc ribe the key netw ork func tions in eac h of the netw ork

domains.

4.1.1.1 End User Domain

End users will be located in residential and non-residential premises and also in non-premises based loca tions such a s pub lic roa d infrastructure (traffic cont rol system s,

street lights, etc .).





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The key func tional comp onents req uired in the end user dom ain a re:

• Outdoor Antenna and Transceiver to p rovide a cc ess to the air interfac e.

• Wireless/ Satellite Network Termina l (WNT/ SNT) provide s RF mo dem func tions to

access the a ir interface. This func tion a lso p rovide s the laye r 2 Ethe rnetinterface to the RG or direc tly to end d evices. It should be noted that this

function is typically integrated with the RG function into a single device in

tod ay’ s layer 3 ba sed de ployments. Howe ver, any future development of laye r

2 services on Satellite/ Wireless technolog ies ma y b ring about the sep arat ion of

these func tions into d istinct de vice s.

• Routing Gateways (RG) which p rovide a laye r 3 (IP) ga teway func tion betweenend devices and the netw ork. They inc lude func tions for: IP rout ing, IP address

a lloc ation to end dev ice s, QoS, Network Address Translat ion (NAT), firewa ll,

ma nag eme nt, Domain Name Server (DNS) and netwo rk authentica tion. A

Retail NSP ma y inc lude a dd itiona l ca pabilities on the RG no t listed above .

• Premises (Hom e) Networks which provide c onnect ivity betwee n end de vices

and RGs.

• End d evices which can be ap p lica tion spec ific (e.g. Set Top Boxes, Phone s) or

mo re g ene ra l in na ture (e.g . PCs).

It should b e no ted that there are m ultiple a rchitec ture o ptions to supp ort multipleservice p roviders delivering services to the p rem ises and wha t op tions a re a pp lied

will dete rmine the ove ra ll level of tec hnica l complexity. This doc ume nt does not

show a ll of the p ossible a rchitec ture op tions. The w holesale RG shown in Figure 6

rep resents only one of the end user architec ture op tions.

4.1.1.2 Access Domain

The func tion of the ac cess do ma in is to provide connec tivity from the e nd user

premises into the netwo rk.

In the c ase o f wireless ac cess, sta ndards define p rotoc ols and proc ed ures to

c ontrol ac cess to the air interfac e, which ope rate s be tween the WNT and the

Wireless Base Sta tion. These w ireless spec ific func tions allow controlled access to

the shared rad io freq uenc y (RF) resources and e stab lishment o f rad io channels

with a ssoc iated QoS.

In the c ase o f sa te llite a ccess, the sa te llite t ransmission systems are p roprieta ry,

requiring a single vendor for the SNT and the Sate llite Mod em Termina tion System

(SMTS). The laye r 2 Ethe rnet service is p rovide d between the SNT on the end userpremises and the SMTS. The SMTSs are loc a ted at Sa te llite Earth Sta tions which a re

typ ica lly dep loyed a t a sma ll numb er of locat ions a round the c ount ry. These Earth

Sta tions ma y be in very rem ote locat ions and will therefore req uire t ransport

services to m ore c entralised loc ations. There could a lso b e multiple STMSs a t aSatellite Earth Sta tion. This ma y drive the need to p rovide a leve l of a gg reg at ion at

this locat ion. It should b e noted tha t due t o the large d elays inherent to satellitebased connec tivity, sa tellite tansmission system s are req uired to support highe r

layer protoc ol a ccelerat ion tec hniques (e.g. TCP ac celerat ion). These tec hniques

should be suppo rted reg ard less of whe ther the satellite system is p roviding layer 2

or laye r 3 service.





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4.1.1.3 Aggregation & Transpo rt Doma in

In the c ase o f wireless access, the Aggregation and Transport doma in p rovide sEthe rnet t ransmission from d istributed wireless base sta tions back to centrally

loc ate d Wireless Ga teways. It should be noted that there may be spe c ific

req uirements plac ed on the Ethernet a gg regat ion a nd transpo rt netw ork tosupport wireless (e.g . support fo r Qo S and sync hronisation o ver Ethe rnet).

In the case of satellite ac cess, the Agg regat ion and Transpo rt d oma in p rovides

Ethe rnet transmission from Sate llite Earth Sta tions, which ma y be loc a ted in remo te

areas, ba ck to more centralised loc ations.

4.1.1.4 Service Edge & Core Domain


ma nage user connec tions ac ross the w ireless do ma in between the Wireless

Ga tewa y and the WNT. The layer 2 Ethe rnet service leve rages these wireless

proto cols and is p rovided betw een the WNT on the end user premises and the

Wireless Ga tew ay. The Wireless Ga tew ays are t ypica lly located in ce ntralised

locations in metropolitan areas.

In the c ase o f sate llite access, the sate llite transmission system b etwe en the Sate llite

Mo dem Transmission Syste m (SMTS) and the SNT is p rop rieta ry. The laye r 2 Ethernet

servic e is p rovided betwee n the SNT and the SMTS. The SMTSs are loc a ted a tSatellite Earth Sta tions which are typ ica lly de ployed a t a sma ll numb er of loc a tions

around the c ount ry. It should b e noted tha t these Earth Sta tions ma y be in veryrem ote locat ions and will therefore req uire t ransport services to mo re c ent ralised

locations.

The NSP func tions in this domain have the sam e func tiona lity a nd access the

Ethe rnet service in the same wa y as the FTTP case d esc ribed in sec tion 3.1.4. Inadd ition to these func tions, suppo rt for QoS ove r wireless access will req uire cont rol

plane interac tion be tween the wireless ga teway and the wholesale/ reta il NSP due

to the d ynamic na ture of rad io bea rer estab lishment/ tea rdo wn.

4.1.1.5 App lication & Co ntent Domain

See sec tion 3.1.5.

4.1.2 Wholesale Point o f Interconnec t a nd Service Boundary Point Scena rios


described in section 4.1.1, there a re a range of p otentia l Wholesa le POIs and

c orrespond ing Servic e Bound ary Points (SBP). These Who lesale POI and SBPscena rios can b e d efined by the service func tionality ava ilab le at the interfac e,

their loc ation and the am ount of ag gregation they provide.

The po ssible loc at ions in the netw ork hierarchy o f the Wholesa le POI and

correspond ing SBP scena rios are show n in Figure 7. Each POI scenario ha s acorrespond ing SBP scenario. The numb ering of the POI and SBP scenarios indic a tes

the a llow ab le POI and SBP pa irings. The service func tiona lity o f ea ch scena rio is

summa rised in Tab le 3.





- 17 -

Figure 7

Wholesale Point o f Interconnec t and Servic e Bounda ry Point Scena rios – Wireless/ SatelliteLayer 2 Ethernet Access

Table 3

Wholesale POI and SBP Scenarios for Wireless/ Satellite Laye r 2 Ethernet Access

POI

Scenario

POI Typ e Servic e Func tiona lity POI Physical Loc ation SBP Physica l Loc atio n

1

Wireless

Layer 2

Ethernet

Wholesale Layer 2

Ethe rnet service to

the end user

premises.

• Aggregation and

transpo rt p rovided by

the wireless network to

a reg ional, state or

national location.

• Ethernet p ort on

the end user

fac ing side of the

WNT.

2

Satellite

Layer 2

Ethernet

Wholesale Layer 2

Ethe rnet service to

the end user

premises.

2a) Satellite Earth Station

2b) Reg iona l, Sta te or

National Aggregation

POI


the end user

fac ing side o f the

SNT.

3Wholesale

L2TP

PPP c onnec tions to

the e nd users

delivered over L2TP

tunnels.

• Reg iona l, Sta te orNational Agg rega tion

POI


the end user

fac ing side of the

RG

4Wholesale

Layer 3 IP


to end user devices


National Agg rega tion

POI


the end user

fac ing side of the

RG





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4.2 Option 2: Wireless/ Satellite Layer 3 IP Ac cess

The fo llow ing sec tions desc ribe the key netw ork func tions in eac h of the ne twork

domains.

4.2.1 Key Network Doma ins and Func tions

The end -to-end netwo rk architec ture c an b e seg regated into a num be r of

func tiona l dom ains as show n in Figure 8. The fo llow ing sec tions will desc ribe the

key network functions in each of these domains.

Figure 8

Broadba nd Network Reference Architec ture – Wireless/ Satellite IP Acc ess

4.2.1.1 End User Domain

End users will be located in residential and non-residential premises and also in non-

premises based locat ions suc h a s pub lic roa d infrastructure (traffic cont rol system s,

street lights, etc .).

The key func tional compo nents req uired in the end user dom ain a re:

• Outdoor Antenna and Transceiver to p rovide ac cess to the air interface.

• Routing Gateways (RG) which provides a layer 3 (IP) gateway functionbetw een end d evices and the netw ork. They include func tions for: IP rout ing, IP

address a lloc ation to end dev ice s, QoS, Network Address Translat ion (NAT),

firewa ll, mana ge me nt, Doma in Name Server (DNS) and netw ork

authent ica tion. The RG a lso p rovide s RF mo dem func tions to a ccess the a ir

interface. A Retail NSP ma y inc lude a dd itiona l capab ilities on the RG not listed

above.





- 19 -

• Premises (Hom e) Networks which provide c onnect ivity betwee n end de vices

and RGs.

• End d evices which can be app licat ion spec ific (e.g. Set Top Boxes, Phone s) or

mo re g ene ra l in na ture (e.g . PCs).

It should b e no ted that there are m ultiple a rchitec ture o pt ions to supp ort multiple

service p roviders delivering services to the p rem ises and wha t opt ions a re a pplied

will dete rmine the ove ra ll level of tec hnica l complexity. This doc ume nt does not

show a ll of the p ossible a rchitec ture op tions. The w holesale RG shown in Figure 8

rep resents only one of the end user arch itec ture op tions.

4.2.1.2 Access Domain

The func tion of the ac cess do ma in is to provide connec tivity from the e nd user

premises into the netw ork.


control access to t he a ir interfac e, which o pe rate s be tween the RG (RF mode m)and the Wireless Base Sta tion. These wireless spec ific func tions allow controlled

ac cess to the sha red radio freq uenc y (RF) resources and esta blishme nt o f rad io

channels with assoc iated QoS.

In the case o f sa te llite a ccess, the sa te llite transmission systems are p roprieta ry,

req uiring a single vendor for the RG and the Satellite Modem Termination System(SMTS). The SMTSs are loc ate d a t Sa te llite Earth Sta tions which a re typ ica lly

de ployed at a sma ll number of loca tions around the c ountry. It should be no ted

tha t the se Earth Sta tions ma y be in very remote loca tions and will therefore require

transport services to m ore c ent ra lised locat ions.

4.2.1.3 Aggregation & Transpo rt Doma in

In the c ase o f wireless access, the Aggregation and Transport doma in p rovide s

Ethe rnet t ransmission from d istributed wireless base sta tions back to centrally

loc ate d Wireless Ga tewa ys. It should be note d that there ma y be spe c ific

req uirements plac ed on the Ethernet a gg regat ion a nd transpo rt netw ork to

support wireless (e.g . support fo r Qo S and sync hronisation o ver Ethe rnet).

In the case of satellite ac cess, the Agg regat ion and Transpo rt d oma in p rovides

Ethe rnet transmission from Sate llite Earth Sta tions, which ma y be loc a ted in remo te

areas, ba ck to more centralised loc ations.

The c urrent a nd future trend for providing aggregat ion and transport networks is to

use Ethernet b ased ag grega tion and transpo rt tec hnology.

4.2.1.4 Service Edge & Core Domain

In the case o f Wireless/ Sate llite IP access two a ccess mo dels can be suppo rted .

The standard app roa ch is to p rovide Wholesale IP access. In this case, the

Wholsa le IP network provides a ll of the Netw ork Service Prov ider (NSP) ne twork

func tions and reta il servic es are p rovide d v ia a resa le mode l (so c a lled White Label

NSP). This sc ena rio a lso supports d irec t a ccess to the Wholesa le IP service b y

ASP/CSPs.

The alternat ive approa ch is for the wireless/ satellite netw ork to p rovide Wholesale

IP-VPN ac cess. This a llow s reta il b roadband NSPs to p rovide som e ne twork





- 20 -

func tiona lity. In this case, the w ireless network provide s IP-VPN co nnec tivity

be tween each reta il b roa dband NSP to the e nd users. The retail b roa dband NSP

provide s a similar set of subsc riber ma nage ment func tions as desc ribed in sec tion

3.1.4. This approach also sup ports reta il layer 3 VPN NSPs. While th is approa ch is

not spec ified in sta ndards, it is supported b y som e wireless vendors. Sup port bysate llite vendors ma y require de velopm ent.

It should be noted that Wholesale IP or IP-VPN Access implies a single national/

reg iona l wholesale prov ider per Wireless/ Sate llite ac cess netwo rk.

4.2.1.5 App lication & Content Doma in

See sec tion 3.1.5.

4.2.2 Wholesale Point o f Interconnec t and Service Bounda ry Point Scena rios


described in section 4.2.1, there a re a range of p otentia l Wholesa le POIs and

correspond ing SBPs. These Wholesale POI and SBP scena rios can be d efined bythe service func tionality ava ilable at the interfac e, their loc ation and the am ount

of a gg rega tion they p rovide.

The p ossible loc a tions in the ne twork hierarchy o f the Wholesa le POIs andcorrespond ing SBPs are shown in Figure 9. Each POI has a c orrespond ing SBP. The

numbering of the POI and SBP scenarios indic a tes the a llow able POI and SBPpa irings. The service func tiona lity o f ea ch scenario is summa rised in Tab le 4.

Figure 9Point of Interconnec t and Service Bound ary Point Scena rios – Wireless/ Sate llite IP Ac cess





- 21 -

Table 4

Wholesale POI and SBP Scenarios for Wireless IP Ac cess

POI

Scenario

POI Typ e Servic e Func tionality POI Loc ation SBP Loc ation

1Wholesale

Layer 3 IP


to end user devices

Reg iona l, Sta te or

National

Agg reg ation POI

Ethernet p ort on the end user

side of the RG

2

Wholesale

Layer 3 IP-

VPN


to e nd user de vices.

Reg iona l, Sta te or

National

Agg reg ation POI

Ethernet p ort on the end user

side of the RG





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5 FURTHER CONSIDERATIONS

Eac h document p rod uced as pa rt of the Com munica tions Allianc e NBN projec t

has a sec tion ded ica ted to the spe c ific issues listed below. The p urpose o f these

sections is to prompt the contributors, participants and persons commenting on thedoc uments to ident ify issues or considerations releva nt to the sec tion. These

sec tions are completed ba sed on information ava ilab le at the t ime o f writing and

ma y change over time.

5.1 Sustainability

The susta inab ility of the Broa dband Network Referenc e Architec ture op tions listed

in this doc ume nt have no t yet b een assessed .

However, co ntributo rs and pe rsons commenting on this do cument are

enc ourag ed to adv ise o f any issues reg ard ing the susta inab ility of the o p tions a t

the ea rliest possible opp ortunity.

5.2 Robustness

The rob ustness of the Broa dband Network Referenc e Architec ture op tions listed in

this do cument have not ye t b een assessed .


enc ourag ed to adv ise o f any issues reg ard ing the rob ustness of the op tions a t the

earliest possible opportunity.

5.3 Security

The sec urity of the Broa db and Network Refe renc e Architec ture op tions listed in thisdo cument ha ve not yet be en a ssessed .


encouraged to advise of any issues regarding the security of the options at the

earliest possible opportunity.

5.4 IPv6

The c ompatibility of the Broa dband Netwo rk Referenc e Architec ture op tions listed

in this doc ument ha ve not yet been a ssessed in light o f IPv6.

However, co ntributo rs and pe rsons commenting on this do cument areenc ourag ed to adv ise o f any issues reg ard ing IPv6 at the ea rliest p ossible

opportunity.

5.5 Future Proo fness

The future proofne ss of the Broa dband Netw ork Refe renc e Arch itec ture op tions

listed in this do cume nt have no t yet been assessed .


enc ourag ed to a dv ise o f any issues reg ard ing future proofness of the op tions a t theearliest possible opportunity.





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6 ABBREVIATIONS

ASP Ap plica tion Service Provide r

AR Ac c ess Route r

CSP Conten t Servic e Provider

BNG Broad ba nd Network Gatew ay

BR Border Rou ter

DNS Domain Nam e Service

EAS Ethernet Ag greg a tion Switch

FTTP Fibre to the Premises

L2TP Layer 2 Tunne lling Protoc ol

LAC L2TP Ac c ess Co nc entrator

LNS L2TP Network Server

NAT Netwo rk Ad dress Transla tion

NSP Netw ork Service Provider

NTU Netwo rk Termina tion Unit

ODF Optical Distribution Frame

ONT Op tica l Netw ork Termination

OLT Op tica l Line Termination

POI Point of Interc onnec t

PON Passive O pt ica l Netwo rkPPP Point to Point Protoc ol

QOS Qua lity of Service

RG Routing Gateway

RSP Reta il Service Provider

SBP Service Bound ary Point

SMTS Sate llite Mod em Termina tion System

SNT Sate llite Ne twork Termina l

VPN Virtual Private Network

WNT Wireless Network Termina l



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Draft National Broadband Network Reference Architecture Oct 2009

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