1、,Philosophy of Building CN2,China Telecom Corporation http:/,Xu Jianfeng,Challenges Total voice traffic and revenue decreases by the end of 2005. The mobile phone and IP phone calls have cannibalized part of the voice traffic businesses Traditional communication network is unable to support China Te
2、lecoms strategy to become a Comprehensive Information Service Provider. This is due to its lack of capability in offering value-added service and service awareness on a unified network. High OPEX (Operating Expenses) is required for operating separate networks in a tradition way The existing ChinaNe
3、t is not best choice for NGN, 3G, VPN and other strict SLA demanding services Opportunities Acceleration of the Information and Communications Technology (ICT) adoption in government and enterprises would drives the demand for telecom services Adoption of the SIP-based soft-switch technology The imp
4、ending releases of 3G license Rapid development of the broadband service Fix and Mobile Convergence ( FMC ),Background,Migration of voice service from PSTN network to IP-based network Preparation for 3G-based mobile services Accelerate the development and deployment of the broadband services base on
5、 xDSL access technology Drive managed service and system integration service Triple play services and future IP NGN convergence including network convergence, service convergence and application convergenceBuilt an Integrated IP/MPLS-based multi-service platform CN2 CN2：China telecom Next Carrier Ne
6、twork,Solutions,Philosophy of Building CN2,Simple network topologyScalable routing architecture Highest level of redundancyHighest level of securityDifferent class serviceDay one support for voice , video and dataEnd to end control and management,Homogeneous Global Architecture Single Global ASN(AS4
7、809) ISIS level2-only with sub-second convergence MPLS FRR with sub-50ms reroute Robust Architecture Allows for Unsurpassed Stability Diffserv-based QOS、MPLS and multicast enabled network 6PE-based IPV6 network Offer Layer-2/3 public/private flexible connectivity over IP or MPLS Leading SLAs via Zer
8、o Loss & Speed of Light Delays Fast automated end to end service provision and fault management utilizing industry leading IP service management solutions, help to greatly reduced OPEX and accelerate service deployment End to end IP SLA monitoring tool make CN2 a true carrier class network,CN2 Stren
9、gth,Simple Network Topology,CN2 comprises of two functional planes and four structural layers to offer a seamless connectivity for customers. The two functional planes are high speed data forwarding plane and service provisioning plane The four structural layers are core layer, aggregation layer, ed
10、ge layer and services connecting layer The high speed data forwarding plane and service offering plane is supported by 4 and 1 vendors respectively. This is to ensure minimum service disruption and better edge services control.,Core,Aggregation,Edge,Service,高速转发层,业务接入层,SR/PE,SR/PE,SR/PE,Simple Netwo
11、rk Topology(cont),IP/MPLS Network All-Optical，Dense Wave Division Multiplexing (DWDM) SONET/SDH framing Per flow load-sharing and fail- over load-sharing with ISIS MPLS is enabled on all network with VPN traffic encapsulated in MPLS and others transported in native IP,MPLS,SONET FRAMING,DWDM,IP,IP,S
12、calable route architecture,To ensure networks scalability and security, only infrastructure address blocks are redistributed into the IS-IS (IGP) routing table. Non-infrastructure addresses are redistributed in BGP. Keeping the IS-IS routing table to a minimum would greatly enhance the network stabi
13、lity. Single Global ASN (AS4809) BGP Communities are deployed for routes control and netflow-based traffic monitor CN2 have two type Route reflector VPN RR for RFC2547-based VPN service,(VRR) Global RR for global internet routing(GRR) VPN RR is independent of global RR, both use one level Route Refl
14、ector(RR) Global iBGP: Scaling the Global Internet Routing Table involve the increase in the number of GRR group,each group handles a part of global routes. VPN iBGP: Likewise, scaling the VPN routing Table involve the increase of VRR group. Example, VPN1-500 is handled by VRR-G1 while VPN501-1000 c
15、an be handled by VRR-G2,Scalable routing architecture (Cont),Full mesh Peers,Full mesh Peers,Internet,GRR1,GRR2,GRR3,GRR4,Client,Client,Client,Client,Group 1 for part1 routes,Group 2 for Part2 routes,Internet,EBGP,EBGP,Scaling the Global Internet Routing Table,Scalable route architecture (Cont),Full
16、 mesh Peers,Full mesh Peers,VRR1,VRR2,VRR3,VRR4,Client,Client,Client,Client,Group 1 for VPN 1-500 routes,PE,PE,PE,PE,Group 2 for VPN 501-1000 routes,scaling the VPN routing Table,Highest Level of redundancy,All network links are deployed in pairs over diverse facilities Only POS interface are used o
17、n backbone link to do faster link failures detection All network links are active (NOT working and protect) Each PoPs router pair is connected by multiple routers. Link failure protection is done through IS-IS (layer 3 control) and not dependent on transport layer (layer 2 control) IS-IS routing pro
18、tocol Per flow load sharing between dual pairs Fail-over load sharing Sub-second fast convergence for gold service Three priority LSP flooding and FIB update MPLS FRR 1:1 mode FRR is deployed in core layer for 50 links Sub-50ms reroute time Built to maintain utilization not to exceed 50% during norm
19、al running As a congestion-free network, CN2 ensures premium priority for delivery of all packets in the core,Higher Level of security,Strict uRPF is deployed on all customer access interfaces Loose uRPF is deployed on interconnected interface Infrastructure ACLs (iACL) deny external traffic to ALL
20、routers interfaces address. iACL are deployed on edges and borders of the network. No one outside network can reach routers Infrastructure routes are not distributed to internet or customer All router access control is managed by AAA servers and syslog QOS technology would be deployed accordingly to
21、 reduce the impact of an attack or worm traffic. All customer facing routers interfaces do not have IGP turn on. When EBGP are deployed on these interfaces, BGP MD5 hash must be configured,Differentiated class service capability,CN2 QoS positioningQoS is used to allocate limited network resources to
22、 different services. Unlike traditional networks of ATM, Frame Relay, and lease circuit services, CN2 provides an uniform network for all these services. To differentiate the services based on the class of importance or contract, QdS is the mechanism in place to segregate and allocate network resour
23、ces to different class of services. Example of a QoS policy: 3G and soft-switch traffic can be allocated with at least 50% of the available bandwidth while Vnet can only consume a maximum of 15% of the total bandwidth QoS are also positioned for traffic congestion management. Under the accidental ci
24、rcumstances of equipment or circuit failures, QoS helps to manage the limited usable network resources to different classes of services. Better resource utilization is expected from deploying QoS. Having elastic policy to re-allocate the under-utilized resources results in efficient resources utiliz
25、ation.,Differentiated class service capability (Cont),QoS design philosophy CN2 adhere to DiffServ framework based on IP precedence and MPLS EXP Bit classification. Thus offering 8 classes of service Initial CN2 service classification is base on 5 basic classes of services. 1 class for network contr
26、ol traffic 1 class for CT internal service 3 classes for service offering All services are classified, remarked, shaped and rate-limited on the edge of the network to ensure a consistent QOS policy enforcement within the CN2 network Service resource allocation is based on class of service. GOLD clas
27、s of service would be allocated with 2 times more redundant resources than BRONZE class of service Convergence of prefix varies on the traffic class. Prefixes of a GOLD class of traffic would converge faster than prefixes of BRONZE class of traffic,Different class service capability,CN2 SLA,Services
28、 are enforced and policed on the edges of the network via the SR/PE device. Service comprises of soft-switch, video conference, VPN, Internet, ATM/FR/DDN etc. To ensure core networks stability and security, service provisioning, new service deployment and security control are performed on the edge o
29、f the network The SOLE responsibility of the Core Network is packet switching and forwarding,All services are Edge Functions,Network Capacity and Coverage (by the end of 2005)：CN2 will provide coverage for 208 cities including Hong Kong, Tokyo, Singapore, London, New York, San Jose, Washington etc.
30、with service offering MPLS/VPN and Internet Services. 671 routers in total，including 439 P routers，208 PE/SR routers，12 Public RR，and 12 VPN RR 1267 relay links with a total link bandwidth of 4.231T Over 800 external interlinkage with a total bandwidth of 2.8T A total customer access link bandwidth
31、of 650.62G CN2 uses Cisco 12416 with E3&SIP line cards as PE routers exclusively to ensure a consistent connectivity and configuration management. This would reduce equipment interoperation issue as well as the speed of problem resolution.,Network Capacity and Coverage,CN2 service capability,Support
32、 MPLS layer 2/3 VPN L3 VPN(RFC2547) Ethernet point to point service(Draft-martini) Ethernet multi point service (Vkompella VPLS) ATM/FR over MPLS Support 3 classes of service. GOLD, SILVER and BRONZE. Support internet & VPN services with SDH、Ethernet/VLAN、ATM/FR/DDN、 L2TPv3, pseudo-wired access Supp
33、ort network wide multicasts of 600 groups,1.2Gbps end to end multicast traffic Support network wide 6PE-based IPv6 with wire speed CN2 uses Cisco 12416 with E3&SIP line cards as PE routers exclusively to ensure a consistent connectivity and configuration management. This would reduce equipment interoperation issue as well as the time of problem resolution, thus be more agile in time to market.,再见,
