ii-nni in the 3gpp standard

GRUPPO TELECOM ITALIA

IIIIIIII----NNI in the 3GPP standardNNI in the 3GPP standardNNI in the 3GPP standardNNI in the 3GPP standard

3GPP release 8 IMS Implementation, Deployment and TestingSophia Antipolis, France

IIIIIIII----NNI in the 3GPP standardNNI in the 3GPP standardNNI in the 3GPP standardNNI in the 3GPP standard

Antonio Ascolese, Telecom Italia

3GPP release 8 IMS Implementation, Deployment and Testing

II-NNI in the 3GPP standard

Main focus

► The need to have IMS NNI profile, with the starting point outside 3GPP or the

starting point in 3GPP

► Main aspects introduced in Rel-8, Rel-9 and Rel-10

► Examples of nowadays applications of II-NNI profile

Antonio Ascolese



The need to have II-NNI

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The need to have II-NNI



Drivers for IP interconnection

► The starting point to define IP interconnection is the IETF RFC 3261 (SIP:

Session Initiation Protocol )

► Hovever the document describes the signaling protocol to be used, but many

implementations in order to provide IP services (telephone calls, multimedia

distribution, multimedia conferences, etc.) are possible

► The need to have a common and shared SIP profile between different

networks (and operators) grows in the evolution framework toward fixed &

Antonio Ascolese

networks (and operators) grows in the evolution framework toward fixed &

mobile all-ip networks

► Drivers of this evolution are

► Telephony � VoIP

► TDM � IP transport

► ISUP � SIP

► enabling new IP services: Video, Presence, IPTV, Messaging, ...



IP interconnection: some of the involved SDOs

Service

Internet

(Unmanaged)

ISP/ASP

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NGN

Service

Operator

Service

Layer

Transport

Layer

NGN

Service

Operator

Service

Layer

Transport

Layer

Managed IP interconnection



ITU-T

► Q.3401 (Q.NNI_profile): NNI profile based on SIP

IP Phone

ProviderB

ProviderA

VoIP

Wireless

LogicalInterfaces

ServiceControl Functions

ServiceControl Functions

This interfaceis the scope of this Recommendation

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IP Phone

BVoIP

VoIP

PSTN PSTN

MG MGSS7

SS7

Wireless

Bearer (RTP/IP)Signall (SIP)

TransportFunctions

TransportFunctions



ITU-T

► The Q.3401 recommendation contains a service-level profile, i.e. SIP/SDP

interface description, between two network operators (NNI signalling profile),

where the two different network operators may support different SIP/SDP

profiles (i.e. they differ in terms of the SIP extensions, SIP information

elements, and SDP lines which are supported)

► The proposed profile is derived from the IETF RFC SIP profile (RFC 3261)

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The proposed profile is derived from the IETF RFC SIP profile (RFC 3261)

► The defined NNI is essentially based on

► voice services

► basic profile (no supplementary services)



ETSI TISPAN Rel2: SoIx and Coix

Session Border ControllerSession Border ControllerSession Border ControllerSession Border Controller

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Service Oriented Interconnection (SoIx): linking of NGN domains including control signalling

Interconnection Service Aware

Service Oriented Interconnection (SoIx): linking of NGN domains including control signalling

Interconnection Service Aware

Connectivity-oriented Interconnection (CoIx):linking based on simple IP

connectivity

Interconnection Service Unaware

Connectivity-oriented Interconnection (CoIx):linking based on simple IP

connectivity

Interconnection Service Unaware



Main aspects introduced in 3GPP

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Main aspects introduced in 3GPP



3GPP: IP interconnection service requirements

► A work item covering service requirements

was approved in SA1 (“Requirements for

Advanced IP Interconnection of Services”)

► To specify the technical requirements for carrier

grade inter-operator IP Interconnection of

Services for the support of Multimedia services

provided by IMS and for legacy voice PTSN/PLMN

services transported over IP infrastructure (e.g.

SA1

service requirements

IPX requirementsSoIx requirements

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services transported over IP infrastructure (e.g.

VoIP)

► Service requirements should take into

account the new and developing

convergent interconnect models currently

being developed outside 3GPP

► GSM A IPX

► TISPAN SoIX

service requirements

stage 2 & 3

II-NNI

stage 2 & 3

SIP-I NNI

TR 22.893

TS 23.228 Annex K

TS 29.165TS 29.235



3GPP activities on IP interconnection (1/2)

► IP Interconnection is being defined in Release 8 between two IMS systems (II-NNI)

IMS IMSBorder

Controller

Border

ControllerBorder controller for:

• Topology hiding, SIP Routing

• Screening and policy,

• Security

SIP NNI

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• ...

► IP interworking is defined in Release 7 between CS PLMN and external SIP-I networks. This

work is the basis for the SIP-I NNI done in Release 8

CS CSBorder

Controller

Border

ControllerSIP-I NNI

SIP-I or BICC or ISUP SIP-I or BICC or ISUP



3GPP activities on IP interconnection (2/2)

CS-IBCF

(CS-TrGW)

IBCF

(TrGW)

SIP-I network

TS 29.235 (nodes)

TS 23.231 29.231 (protocol)

old ITU-T Q 1912.5

(also for ISUP and BICC)

TS 23.228 (architecture)

TS 29.165 (profile)

TS 24.229 (protocol) IBCF

(TrGW)II-NNI

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3GPP network

(TrGW)

S-CSCF

(GW) SIP network

(or IMS nw without IBCF)

3GPP IMS

network

(TrGW)

TS 29.162

TS 29.162

II-NNI

Border element



IP interconnection between two IMS networks (II-NNI)

► Based on TISPAN and ITU-T experiences, 3GPP started to define an NNI

specification for the Inter-IMS Network to Network Interface (II-NNI)

► An initial feasibility study (2H 2007) was done. TR 29.865 “IMS inter-operator service

interconnection interface” identifies the 3GPP protocols and profiles appropriate to

NNI control & user plane interfaces

► Since 2008 the first version of the reference specification for II-NNI (3GPP MTS

29.165) was provided starting from Release 8

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Signalling Bearer

Mx

Mx

IM CN subsystem network A IM CN subsystem network B

Ici

Izi

II-NNI

Mx

Ix

Mx

BGCF Mx

Mx

TrGW Ix

BGCF Mx

Mx

TrGW

IBCF

S-CSCF I-CSCF

P-CSCF

S-CSCF I-CSCF

MSC Server enhanced

for ICS

P-CSCF

MSC Server enhanced

for ICS

Mx

IBCF



Justification of II-NNI

► The IM CN subsystem enables the support of basic voice over IP calls as well

as other multimedia services (e.g. video calls). All of these services require a

well defined Inter-IMS Network to Network Interface (II-NNI) to support

worldwide interoperable communication between IMS networks.

Furthermore a standard II-NNI will help IMS networks to comply

interoperability requirements defined within national and international

regulatory framework

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regulatory framework

► TS 29.165 proposes an Inter-IMS Network to Network Interface (II-NNI)

signalling profile in order to provide a standard reference for service

interconnection between two IMS networks

► The goal is not to define new protocol specifications across these interfaces

(already done in TS24.229), but to identify the protocols and profiles

produced elsewhere in 3GPP that are appropriate to these interfaces.



II-NNI (TS 29.165)

II-NNI profile in Rel-8

CONTROL (Ici)IETF basic profileSIP RFC 3261, SDP RFC 2327/3264RFCs to be used

This approach guarantees the IETF basic session setup

Supported SIP methods & headers Starting from TS24.229

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MEDIA (Izi)

P-header valorization for II-NNI

Protocols

Media Codec negotiationmedia transcodingIPv4/IPv6 interworking

Numbering, Naming and Addressing

Codecs proposed in 3GPP TS 26.114 and ETSI TS 181 005



Example of supported methods

Item Method Ref. II-NNI

Sending Receiving

1 ACK request [13] m m

2 BYE request [13] m m

3 BYE response [13] m m

4 CANCEL request [13] m m

5 CANCEL response [13] m m

5A INFO request [28] o o

5B INFO response [28] o o

8 INVITE request [13] m m

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8 INVITE request [13] m m

9 INVITE response [13] m m

9A MESSAGE request [19] o o

9B MESSAGE response [19] o o

10 NOTIFY request [20] c1 c1

11 NOTIFY response [20] c1 c1

……..



II-NNI profile in Rel-9

Suppl serv. profiles at interconnection

Rel-8 profile update

Support of Major Capabilities

II-NNI (TS 29.165)


Supported SIP methods & headers

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Rel-8 profile update

MEDIA (Izi)

Protocols

Media Codec negotiationmedia transcodingInterlavoro IPv4/IPv6





Example of major capabilitiesItem Capability over the Ici Reference item in 3GPP TS 24.229

[5] for the profile statusProfile status

over II-NNI

UA Role (NOTE 1)

Proxy role (NOTE 2)

Basic SIP (IETF RFC 3261 [13])

1 registrations 1, 2, 2A - c2

2 initiating a session 2B, 2C, 3, 4 - m

3 terminating a session 5 3 m

4 General proxy behaviour - 4, 5, 14, 15, 19F

n/a

5 Forking of initial requests 9,10 6 m

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5 Forking of initial requests 9,10 6 m

8 Timestamped requests (Timestamp header field) 6 - m

9 Presence of date in requests and responses (Date header field) 11 9 m

10 Presence of alerting information data (Alert-info header field) 12 10 o

15 Support and handling of the Call-Info header field - 19C, 19D m

16 Support of the Contact header field in 3xx response - 19E m

Extensions to basic SIP

17 draft-ietf-sipcore-info-events-08 [39]: SIP INFO method and package framework 13 20 o

17A draft-ietf-sipcore-info-events-08 [39]: legacy INFO usage 13A 20A o

20 IETF RFC 3312 [40] and RFC 4032 [41]: integration of resource management and SIP (Preconditions framework)

16 23 o

21 IETF RFC 3311 [23]: the SIP UPDATE method 17 24 m



II-NNI profile in Rel-10 (still in progress)

Suppl serv. profiles at interconnection

Support of Major Capabilities

II-NNI (TS 29.165)


Supported SIP methods & headers Rel-8 and Rel-9

profile update

Support of additional services beyond the supplementary services

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MEDIA (Izi)

Protocols

Media Codec negotiationmedia transcodingInterlavoro IPv4/IPv6



profile updateservices

(ICS, SRVCC, IUT and MSC Server mid-call assisted feature, Presence, etc)

Dynamic profile



II-NNI nowadays applications

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II-NNI nowadays applications



Impacts of II-NNI profile in other standards

► RCS (Rich Communication System) Interworking Guidelines (GSMA)

► Document IR.90 defines that the II-NNI “forms an important part of RCS NNI since

RCS heavily utilizes IMS core system as specified by 3GPP to perform a number of

key duties such as handling of SIP signalling, authentication, authorization,

charging and routing support.”

► IREG (GSMA Inter-working Roaming Expert Group )

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► There is a collaboration between 3GPP CT3 and IREG in order to evaluate if to use

TS 29.165 per IP interconnect scenarios defined in GSMA PRD IR.34 ed

interested by II-NNI aspects

► ETSI TISPAN

► In TS 184 011 “Requirements and usage of E.164 numbers in NGN and NGCN”

(specification under approval) the TS29.165 is mentioned as reference document



Conclusions

► II-NNI is the method suggested to the operators and authorities in order to

provide an effective, stable and deep analysed standard for interconnecting

IMS networks

► II-NNI could be used also for interconnecting IP networks that use a SIP

profile, taking into account that SIP profile is still existing (based on RFC

3261) but this is not enough suited as NNI profile

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3261) but this is not enough suited as NNI profile

► Major effort should be done to

► trasform TS 29.165 as an ETSI standard (ES or EN)

► to adopt the defined profile between the regulatory bodies

► to use TS 29.165 as reference documentaton for interoperability tests



Antonio Ascolese

ii-nni in the 3gpp standard

Technology