88th IETF @ Vancouver Central Controlled IPRAN draft-khy-rtgwg-central-controlled-ipran-00.txt Katherine Zhao(Katherine.Zhao@huawei.com) GuangMing Yong (yanggm@gsta.com) Jiehui Hu (hujiehui@huawei.com)

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

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

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 Page 4

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 Page 5

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

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

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

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

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