ASN Gateway context

ASN Gateway functions

  • Service Flow Authorization
  • Authentication and key distribution
  • Session/Context maintenance
  • Handover co-ordination & Mobility management
  • Paging control
  • Accounting client
  • DHCP proxy/relay
  • MIP client/FA
  • Data-path management and (re)-anchoring
  • Policy Enforcement
  • Multiple BS, ASN, CSN configurations

ASN Gateway Block diagram

Session control

Key control module

  • Co-ordinates and controls other functional modules for all MSS specific functions like network (re)-entry, service flow creation, handover etc.
  • Maintains session state and data, charging context, handover context for both ASN and CSN anchored
  • Initial network entry of the SS/MS (through context related messages)
  • Transfer of contexts to/from ASN GWs/BS
  • Creates GRE/MIP tunnels for traffic flow
  • Session management state machine

AAA functions

  • Pulls the subscriber credentials, attributes from the AAA server over RADIUS
  • Provides AAA attributes to Authenticator, Mobile IP/FA, QoS Manager, DHCP proxy/relay and accounting client

DHCP functionality

  • Helps in deploying access policies (inbound/outbound) specific to the MS
  • Helps in hiding the identity of the MS (option 82)
  • Helps in managing the address: Site specific address, Global address, Address lease time
  • Establishing default route and DNS
  • Address allocation server address configured at ASN GW (can be in visited or another network)
  • Relays DHCP messages between DHCP client on SS/MS and Address allocation server.

Authentication

  • EAP procedure initiation on MS/SS entry
  • Authentication relay protocol mapping to AAA protocol (for example EAP over RADIUS)
  • Multiple types of authentication. Device authentication/user authentication/Combined authentication

Paging control

  • Handles one or more paging groups
  • Connects to other Paging Controllers in the network
  • Initiates page to paging agents
  • Updates location register whenever MS moves in/out of IDLE mode or when MS updates own location

Accounting

  • Service flow based accounting procedures
  • Interim accounting updates
  • Offline and Online (pre-paid) charging
  • Ability to store UDRs in events of temporary loss of connection to accounting server
  • Hot-lining support

QoS management

  • Acts as S-SFA/A-SFA in the ASN GW
  • Interfaces to AAA client for policies stored in the HAAA
  • Interfaces to PF for policy data requests/responses
  • Does admission control for service flows based on local policy and resource availability
  • Location update to S-SFA or PF
  • Handles MS initiated as well as network initiated service flow requests on R6 interface
dataPath (pre)registration/(pre)deregistration in conjunction with Handover.
  • Pre-provisioned and dynamic service flows

GRE client/FA

  • GRE tunnel management towards R6/R4
  • MIP registration and de-registration with HA
  • Inter-ASN mobility to establish new MIP tunnels
  • MIP Advertising to support CMIP
  • Mobility context update to the session manager
  • Support for Client MIP (Care of address advertisements, )
  • Controls DHCP gating

Platforms

  • ATCA based with high speed packet processing engines
  • Proprietary with high speed packet backplanes
  • Distributed & stackable
  • Use existing platforms offering similar throughput and tailor to support ASN GW function – examples could be GSN and PDSN
An ATCA based ASN G/W solution


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