Admission Control in IP Multicast over Heterogeneous Access Networks

1
Admission Control in IP Multicast over
Heterogeneous Access Networks

• Pedro Santos (PT Inovação)
• António Pinto, Manuel Ricardo (INESC Porto)
• Franscisco Fontes, Teresa Almeida (PT Inovação)

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Outline

• Introduction
• IP Multicast
• Reference Network Scenario
• UMTS / xDSL / WiMAX
• Proposed Solution
• Results
• Conclusions

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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

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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)

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IP Multicast
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IP Multicast

• IP Multicast ? Open architecture
• Receivers are free to join any group
• Sources are free to transmit to any group
• Makes IP multicast-based commercial services
  difficult to implement
• Solutions
• End-to-end encryption of data streams
• Control access to multicast sessions

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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

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Reference Network Scenario
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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

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

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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 _at_ ASN-GW

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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)

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Multicast Control - MSC
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Prototype (Multicast Controller)
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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/unauthoriz
  ed group
• unauthorize a source/member after
  transmission/reception has begun
• Processed up to 1250 IGMP requests/sec

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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

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Questions

• ?