Transcript Operator Discussion on Network Architecture Evolution

Evolution Architecture Functional Proposal
Abstract:
This contribution proposes a new architectural network element called an
Access Gateway (AG).
Source:
Brent Hirschman, Sprint Nextel – [email protected]
Jingyi Zhou, Verizon Wireless – [email protected]
Date:
December 4, 2006
Recommendation:
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Review and adopt proposal for AG.
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Objectives of Evolved Architecture
 Realize improvements in basic system performance
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Provide higher data rates
Reduce communication delay
Improve communication quality – end to end QoS
Reduce connection set-up time
Provide separation of control signaling and transport paths from RAN to
Core
 Provide increased security and privacy for users and network
 Support of a variety of access technologies
 Seamless mobility across technologies
 Maintain access control across technologies – authentication, authorization,
privacy, charging
 Service continuity across technologies – access to same service (e.g., IMS)
 Improve Operations and Maintenance Capabilities
 Reduce Complexity
 Simplify Network Architecture
 Encourage “Mix and Match” capabilities for RAN and IP vendors – preserve
standardized open interfaces
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Current Reference Architecture
Interface
Not Implemented
Open Interface
Interface Undefined
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Current User Plane Protocol Stack
TCP
UDP
TCP
UDP
IP/MIP
IP/MIP
RLP
RLP
Sublayers
of HRPD
PHY
Sublayers TCP/UDP
of
IP
HRPD
HDLC
GRE
GRE
IP
IP
Ethernet
PHY
ATM
ATM
PHY
PHY
PHY
TCP/UDP
IP
T1
T1
PHY
Ethernet
IP over ATM
IP Backhaul
BTS
ATM
ATM
ATM
ATM
PHY
PHY
PHY
PHY
IP
IP
HDLC Ethernet
T1
AT
IP
RMI
RMI
HRPD
IP/MIP
PPP
PPP
Aggregation
Router
IP over ATM
IP over ATM
R-P (A10/A11)
RNC
PDSN/FA
HA
Application
Server
Evolution needs to consider the following operators’ goals:
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Separation of access and IP networks
Simplification of RAN/PDS Interface
Minimize number of elements in bearer path and support low latency bearers
Standards based Interfaces in the RAN and at RAN/PDS interfaces
Leverage IP technology for backhaul and core networks
RAN Security considerations for privacy, confidentiality, Man-in-the-middle
(MITM) and Distributed Denial of Service (DDoS) attacks
 Support for both Home and Visited Network Control for IMS and other services
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Proposed New User Plane Protocol Stack
TCP
UDP
TCP
UDP
IP/MIP
IP/MIP
ROHC/Sec
RLP
IP/MIP
IP
ROHC/Sec
RLP
GRE
GRE
MAC
PHY
AT
MAC
PHY
L2
L2
L2
L2
PHY
PHY
PHY
PHY
IP
IP
L2
L2
PHY
PHY
IPGW
NG-BTS
Core
Evolved RAN Architecture has the following features:
 Centralized Layer 2 functions like paging, location management, and idle state management
 Complete link layer stack in the NG-BTS to allow for cross-layer optimization in airlink protocol
Evolved PDS Architecture has the following features:
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ROHC and Ciphering (considered between link layer and IP layer) terminate in the PDS
PPP Free Operation
EAP Authentication mechanisms
Mechanisms to set up Low latency bearers for real-time services
AT – Access Terminal
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NG BTS – Next Gen Base Terminal Station
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IP GW – IP Gateway
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Proposed Edge Functional Element Access Gateway
AG – Access Gateway - This function is the Layer 3 terminating point for all
bearer and signaling traffic entering the Core IP Network. It also supports
the following functions:
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AAA client
NAS (Network Access Server) device
IDS (Intrusion Detection System) access point
Hot-lining device
Prepaid client
Foreign Agent (FA) for MIPv4
Network Mobility Agent for localized network mobility (NMA)
QoS enforcement point
Policy enforcement point
NFCC (Network Firewall Configuration and Control) packet filter
IAP (Intercept Access Point) (lawful Intercept)
ROHC (Robust Header Compression)
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Lower Layer Termination Functionalities
- Specific to an Access Technology
There are two main aspects to this functional area:
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Signaling – Mobility management (similar to the signaling management in current
RNCs) above the radio layer (RLP) between Base stations served by the same Access
Gateway. These functions include:
 Paging and location– In a pure IP mobile network a paging controller function to
locate mobiles when idle will be needed.
 Idle Mode Termination – Some State information about the MS needs to be
maintained by the network while the MS is in idle mode.
Bearer - Mobility management of the bearer flows to the Access Gateway. Tunnel
establishment and tear-down between Base Stations and Access Gateway.
Independence of the Signaling and Bearer functions is important. Separate
standardized interfaces for Signaling and Bearer functional components are needed.
Implementation scenarios are subject to operator’s preference.
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IP Core Network
Access Gateway
IP Signaling
and transport
(e.g., SIP)
AAA
Policy and QoS
AG
Layer 3 Common Functions
Other AGs,
Legacy NEs
(e.g., PDSNs, SGSN/GGSN)
And new NEs (e.g., ASN-GW, PDIF)
FA/NMA
NAS device
AAA Client
QoS EP
Lawful Intercept IAP
Policy EP
NFCC Packet Filter
Prepaid Client
Hot-lining device
IDS/IPS Access Point
ROHC
Ciphering
Lower Layer Termination Point
Support for Bearer Management
Std
Interface
Std Interface
Signaling
Management
(S-RNC)
Paging and
Location
Idle Mode
Termination
Std Interface
Various Access Network
Technologies
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Access Gateway – Supporting Current
and Proposed Evolved Architecture
AAA
PCRF
IP Core Network
HA/BM
Common Functions
PDSN
FA/NMA
QoS EP
NFCC Pkt Filter
AAA Client Policy EP Prepaid Client
Lawful Intercept IAP NAS Dev. Hot-lining device
IDS/IPS
ROHC
Ciphering
P-P
Current Access
LLT
(PPP/PFO)
Proposed Access
LLT
PFO
P-P’
IP Gateway
Non-trusted
Access
LLT
(IP-Sec)
A10/
A11
RNC
Bearer
S-RNC
Signaling
AP
EV-DO Rev.A
BS
BTS
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EV-DO Rev.C
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WiFi (802.11)
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Handoffs within and across Access Gateways
Handoff DO-Rev.A – DO-Rev.C
Handoff DO-Rev.C – DO-Rev.C
In different AG
Handoff DO-Rev.C – WLAN
Handoff DO-Rev.C – DO-Rev.C
In the same AG
AG
AG
Layer 3
Current Access
Layer 3
P-P’
Proposed Access
LLT
(PPP/PFO)
Proposed Access
Bearer Mgmt
Bearer Mgmt
Non-trusted
Access
LLT
(IP-Sec)
A10/
A11
RNC
Bearer
S-RNC
S-RNC
Signaling
AP
BS
BS
BS
BTS
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