1. 88th Vancouver
Central Controlled IPRAN draft-khy-rtgwg-central-controlled-ipran-00.txt
Katherine
GuangMing Yong
Jiehui Hu

2. Introduction
IP RAN (Radio Access Network) is a run solution using IP technology to provide network services between UE devices and mobile core network.
IP RAN has been widely used to provide varies access modes with high scalability and flexibility, it reduced network construction cost and protects codes of investments.
However the existing IP RAN implementation needs to be improved due to
Manual configuration Point-by-Point
Complex network construct and service deployment
Low troubleshooting efficiency
Central Controlled IP RAN (SDN enabled) can further improve the IP RAN and resolve these problems
Page 2

3. Central Controlled IP RAN Use Case
Applied in China Telecom’s Access and Aggregation Network
ATM RNC
IP RNC/S-GW/MME
BSC
STM-1 GE
LAST MILE
ACCESS
AGGREGATION
LTE/WiMax
Enterprise
UMTS HSPA
UMTS R99/R4
GSM/GPRS FE
ML-PPP E1
TDM E1
IMA E1
RNC/SGW/MME
RSG
CSG
AGG
Controller
Main
Backup
Control Agent
Central Controller

4. CC IP RAN Network Architecture
ASG: Aggregation Service Gateway
BS: Base Station
CSG: Cell Site Gateway
RSG: Radio Service Gateway
BS1
BS2
RNC/SGW/MME/BSC
MPLS
TDM/ATM/Ethernet
RSG
CSG
ASG
BS1
BS2
SDN Domain
Controller
RNC/SGW/MME/BSC
Control
Agent
Forwarding Node 1
Base Routing
Forwarding Node 4
Forwarding Node 2
Forwarding Node 5
Forwarding Node 3
Forwarding Node 6
NMG
MPLS
TDM/ATM/Ethernet
Third Party App
Conversional IP RAN Network
Major Control functions are moved to controller from network devices
Controller has E2E control capability
Access, Aggregation and RSG are forwarding devices.
Programmability of controller
Open to third party applications
Central Controlled IP RAN Network
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5. System Architecture Controller MPLS en-caped packet HOST ASR 9K
Functions of Controller
CP-DP control protocol features
Network resource management features
Network virtualization features
Network protocol layer, IGP,LDP/RSVP
Network service layer,L2 (VPWS/VPLS) VPN, L3 VPN
Fault, Alarm, NB-API
MPLS en-caped packet L2
Label
Payload
HOST ASR 9K
(single chassis OR cluster)
Controller
Access Node 1
CP-DP
MPLS internal network
Without LDP
Access Node n
Functions of Forwarding Node
IP/ MPLS forwarding
CP-DP protocol features
Control Agent
Light IGP for connectivity
The functions of IPRAN-CP:
o CP-DP control protocol features: provide forwarding device control
information; establish and maintain connections between control
plane and the forwarding nodes. CP-DP protocol can be XMPP,
Openflow, or a newly defined protocol.
o Network resource management features: discover and collect the
forwarding nodes, the ports on the nodes as well as topology
resources in the IP RAN domain. Other software modules can use
the resource collection to calculate path, deploying services, and
build forwarding tables etc. IPRAN-CP should also open to network
management applications and third-party applications to programm
and manage the network resources.
o Network virtualization features: abstract network and shield the
physical network details from the service layer. Operational
service deployment can be done based on virtual network without
concernning how forwarding path for the virtual network to get
through at the lower layer. In IP RAN, the transport uses MPLS,
the network virtualization here means MPLS virtualization.
o Network protocol layer: provides traditional routers supported
conventional routing protocol stack, which was running on the
forwarding nodes. Now these features are moved up to the central
controller.
o Network service layer: Supports IP RAN required L2VPN and L3VPN
services. L2VPN including VPWS and VPLS.
o Supporting module: provides basic tools include fault location,
alarm, northbound interface for maintenance and management
capabilities.
The functions of forwarding node:
o Basic routing features: run IGP routing protocol and responsible
for establishing connectivity with other devices, setup routes and
collect topology. It must be done before a controller can
communicate with the network devices.
o Control protocols: corresponds to the control protocol running on
the IPRAN-CP device, responsible for establish and maintain CP-DP
connection.
o Control Agent: Responsible for the registration with IPRAN-CP;
reporting its information to the controller; accepting control
information and forwarding tables distributed by the IPRAN-DP.
Control Agent is also responsible to install the forwarding tables
to the data plane that is used to guide the traffic forwarding.
o Forwarding Plane: forwarding and procession of messages and user
traffics.
XXX [Page 16]
Internet-Draft Central Controlled IP RAN July 9, 2013
o Support module: provides debug and diagnostics functions on
forwarding nodes; supports device management features; provides
interface to network management (include power supplies, voltages,
etc).
Low Cost Device
Open Architecture
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6. Controller Deployment Options
BS1
BS3 I1 I2
SDN Domain
RNC/SGW/MME/BSC
Control
Agent
CSG1
Base Routing
SDN Controller
ASG1
ASG2
RSG1
RSG2 I6 I4 I3 I5
Built-in Mode:
Controller on Device
BS1
BS3 I1 I2
SDN Domain
SDN Controller
RNC/SGW/MME/BSC
Control
Agent
CSG1
Base Routing
ASG1
ASG2
RSG1
RSG2 I3 I5
Stand-along Mode:
Controller on Server
Page 6

7. Central Controlled IP RAN
Central Controlled IP RAN Overview
Mobile Backhaul
Central Controlled IP RAN
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
CSG
BTS
NodeB / eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
AGG
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
BTS
NodeB / eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
CSG
AGG
Main
Backup
Central Controller
Control Agent
Control Plane
Control Plane
Control Plane
Simple O&M
Free Service Planning, Plug and Play
Automatic protocols deployment and fast services launch
Fast trouble shooting
Manual configuration
point-by-point

8. Mobile Backhaul： Complex services planning
Free Service Planning, Plug and Play
Planning IP Address
Dividing IGP Area
Planning CSG&AGG ring relations
Mobile Backhaul： Complex services planning
Main
Backup
Central Controller
Control Agent
Planning IP Address
Dividing IGP Area
Planning CSG&AGG ring relations
SDN-based Mobile Backhaul：Free Services Planning
CSG
AGG
Saving
Plug and Play，Zero Touch for Basic Network
Current IP RAN
Access Solution
Central Controlled IP RAN
IGP
Yes
Automatic deployment
RSVP-TE No
Solution
Protocol

9. Automatic Protocols Deployment and Fast Services Launch
Mobile Backhaul
Central Controlled IP RAN
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
BTS
NodeB / eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
AGG
CSG
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
BTS
NodeB / eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
CSG
AGG
Control Plane
Main
Backup
Central Controller
Control Agent
IGP/LDP/RSVP
Virtual-cluster enable
Configure remote-interface
L2VPN
IGP/LDP/RSVP
L2VPN
IGP/LDP/RSVP
IGP/LDP/RSVP
IGP/LDP/RSVP
Protocol-based point-by-point services launch
Service-based end-to-end services launch
Simple protocol Automatic configuration
Lowers skill requirements of staff
Improves efficiency of services launch

10. SDN-based Mobile Backhaul
Fast Trouble shooting
Mobile Backhaul
SDN-based Mobile Backhaul
Each node sends alarm independently
NMS
Trouble shooting on each node
Alarm analysis for Locating root causes of fault
NMS
Trouble shooting only on Central Controller
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
CSG
BTS
NodeB/eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
AGG
ATM RNC
Last Mile
Access
Aggregation
RNC/SGW/MME
RSG
BTS
NodeB/eNB E1
Eth
IP RNC/S-GW/MME
NodeB
ATM
BSC
STM-1 GE
CSG
AGG
Control Plane
Main
Backup
Central Controller
Control Agent
failure
failure