Portugal Telecom Inovação, S.A. / INESC Porto

Admission Control in IP Multicast over Heterogeneous Access Networks

Pedro Santos (PT Inovação)Pedro Santos (PT Inovação)

António Pinto, Manuel Ricardo (INESC Porto)António Pinto, Manuel Ricardo (INESC Porto)

Franscisco Fontes, Teresa Almeida (PT Inovação)Franscisco Fontes, Teresa Almeida (PT Inovação)

Outline

• Introduction

• IP Multicast

• Reference Network Scenario– UMTS / xDSL / WiMAX

• Proposed Solution

• Results

• Conclusions

22 Apr 2023 2NGMAST'08

Introduction

• The general goals of this project were:

– To design a solution capable of performing• multicast receiver access control (e.g. TV channels)

• multicast sender access control (e.g. User generated content)

– ... in an heterogeneous access network scenario

– Implement a prototype for validation purposes

22 Apr 2023 3NGMAST'08

IP Multicast

• One data stream per group of receivers– Packet replication done by network nodes– Multicast groups represented by IP addresses

• (* ,G) Any-Source Multicast (ASM)

• (S,G) Source-Specific Multicast (SSM)

• Group management– IPv4 Internet Group Management Protocol (IGMP)– IPv6 Multicast Listener Discovery (MLD)

• Forwarding protocols– Protocol Independent Multicast (PIM-SM/SSM/BiDir)– Distance Vector Multicast Routing Protocol (DVMRP)

22 Apr 2023 4NGMAST'08

IP Multicast

22 Apr 2023 5NGMAST'08

IP Multicast

• IP Multicast Open architecture– Receivers are free to join any group– Sources are free to transmit to any groupMakes IP multicast-based commercial

services difficult to implement

• Solutions– End-to-end encryption of data streams– Control access to multicast sessions

22 Apr 2023 6NGMAST'08

Objectives• IP multicast streaming over heterogeneous access

networks– UMTS, xDSL, WiMAX

• Identify network nodes where to perform– access control– authorization– resource management

• Support for multicast sources– in the core network (known & authorized SP) – in the access network (user generated content)

• Authentication, authorization and record of multicast sessions

• Implement a prototype to validate the proposed solution

22 Apr 2023 7NGMAST'08

Reference Network Scenario

22 Apr 2023 8NGMAST'08

UMTS• GGSN Multicast router

• Native multicast support– Multimedia Broadcast/Multicast Service (MBMS)

• New functional element (BM-SC)• Inter-operable with IP Multicast (IGMP & IPv4 Class D)• Only for downstream traffic

– The reference point from the content provider to the BM-SC is not standardised by 3GPP in this release of the specification. “3GPP TS 23.246 v8.2.0”

22 Apr 2023 9NGMAST'08

xDSL

• BNG/BRAS Multicast router

• DSL-Forum TR-101 – Two Connection types– PPPoE

• Point-to-point connection CPE BNG• Packet replication done at the BNG Access control to multicast flows @ BNG

– IPoE• Every network element performs packet replication• L2 control over packet replication necessary at the DSLAM Access control to multicast flows @ BNG and DSLAM

22 Apr 2023 10NGMAST'08

WiMAX• ASN-GW Multicast router

• SS ASN-GW connection– Identified by a 16bit number (CID)– Upstream unicast connections (exclusively) – Downstream multicast connections possible (mCID) but...

• mCID are unidirectional in nature• not fitted for power-conservative systems• only efficient for large groups (nº of subscribed SSs)

Access control to multicast flows @ ASN-GW

22 Apr 2023 11NGMAST'08

Proposed Solution• User authentication

– Done at network attachment

• Access control done at the network access node– Members detection IGMP messages– Sources detection UDP multicast messages– Access Authorization AAA server– Policy Enforcement Access Control Lists (ACLs)

• Multicast profile per user/subscriber

• Multicast session id– IP header Source address (SA), destination address (DA)

– IGMP message Group source address (GSA), group destination address (GDA)

22 Apr 2023 12NGMAST'08

Multicast Control - MSC

22 Apr 2023 13NGMAST'08

Prototype (Multicast Controller)

22 Apr 2023 14NGMAST'08

Results

• Multicast controller basic functionalities– authenticated user detection/verification– detection of multicast join/leave messages– detection of multicast source transmissions– multicast authorization checks– multicast traffic filtering (according to authZ checks)

• Successful functional validation– authorized/unauthorized group join request– multicast transmission to an authorized/unauthorized group– unauthorize a source/member after transmission/reception

has begun

• Processed up to 1250 IGMP requests/sec

22 Apr 2023 15NGMAST'08

Conclusions

• Multicast control done at access node– GGSN (UMTS)

– BNG or BNG & DSLAM (xDSL)

– ASN-GW (WiMAX)

• Application & Network agnostic– No changes needed to applications or network protocols

– Minimal user impact (only network elements are affected)

– Access control done at network layer

– ... L2 control may be required (If L2 packet replication)

• Access control is subscriber “centric”

22 Apr 2023 16NGMAST'08

Questions

?22 Apr 2023 17NGMAST'08