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)

2. Outline Introduction IP Multicast Reference Network Scenario
UMTS / xDSL / WiMAX
Proposed Solution
Results
Conclusions
April 17
NGMAST'08

3. 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
April 17
NGMAST'08

4. IP Multicast One data stream per group of receivers Group management
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)
April 17
NGMAST'08

5. IP Multicast
April 17
NGMAST'08

6. IP Multicast IP Multicast  Open architecture Solutions
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
April 17
NGMAST'08

7. 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
April 17
NGMAST'08

8. Reference Network Scenario
April 17
NGMAST'08

9. 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 v8.2.0”
April 17
NGMAST'08

10. 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 BNG
IPoE
Every network element performs packet replication
L2 control over packet replication necessary at the DSLAM
 Access control to multicast BNG and DSLAM
April 17
NGMAST'08

11. 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 ASN-GW
April 17
NGMAST'08

12. 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)
April 17
NGMAST'08

13. Multicast Control - MSC
April 17
NGMAST'08

14. Prototype (Multicast Controller)
April 17
NGMAST'08

15. 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
April 17
NGMAST'08

16. 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”
April 17
NGMAST'08

17. Questions ?
April 17
NGMAST'08