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CNC: A Key Step to Next-Generation IP Bearer Network
CNC, China Network Communications, is seeking to boost its competitive edge via technological developments and service optimization. To achieve this, its key strategic goal rests with constructing a sustainable, valued and cost effective NGN & 3G based IP bearer network.

CNC has emerged as one of China's largest fixed network and broadband carriers since its inception. A relatively new company established in 2002, CNC arose from the former China Telecom (10 northern provinces), CNC Communications and Jitong Communications. Having subsumed these companies, CNC now owns their resources and has inherited their operations in northern Chinese provinces, and is exploring and cultivating markets in southern China.

Fixed network carriers have witnessed a marked decline in ARPU derived from fixed-line services, and are therefore having to turn towards opportunities offered by new services such as NGN, IPTV or 3G. Strategic transformation from traditional carriers to new-type carrier reflecting current technological trends must occur in order that the necessary service breakthroughs are made to ensure competitive expedience.

CNC's role as a fixed-telecom service partner in the 2008 Olympic Games has highlighted both the challenges and opportunities brought about by evolving technology. Implementing its transformation partly by putting in play its broadband strategy, CNC is actively tracing new technologies and services. With CNC's new service trials, bearer network development has emerged key to backbone network construction.

What's the Best? IP, TDM or ATM?

CNC possesses a complete ATM network with relatively few services. The complexity of ATM technologies limits the number of supporting vendors, and applications are mainly concentrated on data leased line service. It is commonly understood that ATM will give way to IP, therefore decreasing the viability of new service deployment on ATM networks.

As for TDM, CNC has rich resources and a complete network with 100 million fixed-line subscribers. TDM's complicated full-mesh architecture, however, describes a network topology requiring high investment in terms of both construction and maintenance.

IP is the developmental direction of future networks. NGN integrated services, 3G PS domain services and IMS are all based on IP kernel. In the future, fixed-mobile convergence (FMC) will rely on IP bearer networks and therefore a unified IP bearer network is both the prevailing development trend and a necessity for carriers' service and network transformation.

As one of China's largest Internet service providers, CNC has constructed a nation-wide Internet network for public use. Considering the heavy network loads, security and openness, the network is only suitable for Internet services, but not suitable as NGN bearer networks.

Faced with the existing conditions of its backbone networks, CNC has made a long-term decision to construct a brand-new IP bearer network oriented to the NGN toll network and 3G services. It is expected that the network will utilize cutting-edge technologies to ensure that the service loads and requirements of the future can be met.

The Advantages for Constructing a New IP Bearer Network

A high start point

The new IP bearer network is specially designed to bear NGN or 3G services, which is very demanding in terms of QoS, security, IP addressing and scalability. Network performance, the ability to bear future services and bandwidth utilization are central construction parameters.

Not only does the network need to be based on the types of services that will be borne, consideration must also be given to the fact that NGN and 3G networks enable special service models such as a star-shaped signaling traffic model and a mesh-shaped media stream. Network link bandwidth planning and equipment selection of course needs to reflect these features.

Table 1 QoS indexes for NGN services

Application type

Typical service

E2E uni-directional average time delay

E2E uni-directional average jitter

E2E uni-directional average packet loss rate

Bandwidth requirement

Real-time voice/video

NGN voice, video telephone

150ms

20ms

0.1%

Guaranteed

Real-time data

Signaling

150ms

N/A

0.1%

Guaranteed

Stream media video

IPTV, VOD

1000ms

N/A

0.1%

Guaranteed


As illustrated in Table 1, the new IP bearer network fully considers NGN service bearing requirements: detailed provision is made for QoS, security and reliability indexes and new IP bearer technologies are adopted for network solutions, such as DS-TE, NSF, VPN, route protocol fast convergence and BFD. Increased reliability by inclusion of milliseconds fault switchover; Ease of management and maintenance due to simplified network architecture, which is facilitated by high-capacity equipment and a flat networking model; IPv6 addresses are supported due to the adoption of IPv6 network equipment.

CNC's IP bearer network not only caters for the bearing requirements of NGN services, it can also be used as the bearer platform for 3G and other services. With the network's capacity for expansion and its ability to adapt to future services, gains in CNC's competitiveness are expected.

Low risk

The new IP bearer network for NGN adopts many risk reduction measures. While traditional Internet networks cannot meet bearing requirements in terms of service security and bandwidth guarantees, NGN services are carrier-class services capable of doing so. Additionally, traditional Internet services are directly oriented to end-users and offer open interfaces to other networks. Attacks from hackers can directly affect network and services' security.

The new IP bearer network is not oriented to ordinary users and this ensures high network enclosure and security. Moreover, it is not influenced by other network services and does not compete for their resources. By deploying NGN services, the network can easily enable fault location and diagnostics, and remove influences from other services such as addressing and routing.

Lower cost & quicker deployment

If the existing IP network is reconstructed to meet NGN service bearing requirements, high reconstruction costs are entailed. However, the overall costs for constructing a new IP bearer network are relatively low. The new network is unaffected by an existing network's architecture and services, as a result, the new network can be quickly deployed.

OPEX reduction

The newly constructed IP bearer network adopts complete VPN service network management (NM) and QoS service NM to enable centralized NM in the network. OPEX can therefore be reduced.

CNC Launches its National Broadband IP Bearer Network

After detailed technical analyses and research, CNC decided to construct a brand-new NGN bearer network based upon the feature of NGN & 3G horizontal traffic. Horizontal networking design and new technologies such as FRR are adopted. The network differs vastly from CNC's traditional network layout and marks an important step towards network transformation.

The new broadband IP bearer network adopts carrier-class IP design ideas, and integrates plenty of IP technologies with the in-depth understanding of traditional carrier-class services. This not only enables high-performance service forwarding, but also integrates the planning experiences of traditional telecom networks and CAC mechanisms. By using QoS measurement and redeployment, the network allows long-term QoS operability and maintainability, thus strictly guaranteeing QoS, reliability and security, and ensuring the smooth deployment of NGN services.

In terms of equipment, the reliability is further improved within the new network, possessing both multi-service bearing capability and scalability. The core equipment ensures 99.999% reliability and new technologies are employed to increase network stability, including non-stop forwarding, BFD/OAM, fast convergence and rerouting. The equipments fully support MPLS VPN, IPv6, multicast and QoS features. If new services are added, the network can be directly upgraded without replacing any hardware board.

The new network adopts VPN NM, allowing for the quick deployment of MPLS VPN. Traffic collection and analysis is designed to analyze each node's traffic flows, which assists the planning and expansion for NGN services.

In addition to NGN services, the new network is able to bear 3G and other valued telecom services. The IMS in the future will be a unified network characterized by mobile and fixed network convergence, and this of course requires a unified IP bearer network. The newly constructed multi-service IP bearer network provides the foundation for CNC's future network developments and is set to become a unified bearer platform for new telecom services.