1 The Birth of IPv6
The future communication mode based on the IP protocol is taking shape with the rapid development of the mobile Internet, convergence of voice and data and embedded interconnection equipment. People´s lives have experienced great changes by the success of the Internet that has penetrated all aspects of the society. At the same time, the development of the Internet has become an important component of construction of the information-based and modernized society, which brings great economical and social benefits. The wide application and rapid development of the Internet are owed to IP4, the core technology for the Internet. The IP4 technology succeeded because of its concision and effectiveness.
However, IPv4 was made as early as 1973, and its designers had no ideas about such a development speed and scale at that time. Therefore, the limitation and hidden crisis of IPv4 emerged in the 1990s. The biggest problem of IPv4 is the shortage of IP address resources. The IPv4 addresses are possible to be used up around 2010, according to experts´ estimation. In addition, there are a series of other problems in hugeness of the route table, Quality of Service (QoS) and mobility.
The birth of IPv6 not only solves the shortage of addresses in the IPv4 network, but also provides some new mechanisms to the limitations of IPv4, which brings more benefits to the next generation network.
- IPv6 adopts the simplified packet header, which cuts down the overhead of the processor and saves the network bandwidth. At the same time, IPv6 defines multiple extension packet headers, which makes IPv6 greatly flexible to support diversified applications, and makes it possible to match new applications in the future.
- IPv6 introduces hierarchical address architecture, and divides the IPv6 address space according to the different prefixes of the addresses, which is good for the backbone network router speedily forwarding the data packets.
- The "plug-and-play" mode of hookup is introduced in IPv6, so an IP address will be automatically assigned to the user as long as the device is conneted to the network. This avoids the terminal user from exhaust himself to configure the address, and greatly lightens the burden on the network administrator at the same time.
- Authentication and encryption of the network layer is an essential part of IPv6, while IPsec is a necessary option, which provides security services such as the encryption and identification of data packets at the network layer, and guarantees the network security.
- A 20-bit flow label is newly added in the IPv6 data packet format. When an information packet is received by the intermediate IPv6 node, its flow type is recognized by the flow label. Then its QoS requirement is known, and rapid forwarding is implemented. More assurance for QoS is accordingly offered.
- IPv6 have more and better features than IPv4, and can provide better support for mobile communication.
2 China Next Generation Internet (CNGI)
The research and construction of the Next Generation Internet (NGI) based on the IPv6 is attached importance in many countries, since more and more problems of the IPv4-based Internet have been exposed while the IPv6 technology is showing its advantages. The research and establishment of the NGI was initiated in USA in 1996. US National Science Foundation has launched an NGI plan to support universities and research institutes to establish the very High-speed Backbone Network System (vBNS) for the research and development of high-speed computer network and its applications. University Consortium for Advanced Internet Development (UCAID), a university consortium of 125 members in US, was founded in 1998. It works on Internet2 projects and on projects related to Abilene, an individual proving ground for high-speed network. Abilene began to offer services in January 1999. Several other developed countries such as UK, Germany, France, Japan and Canada have also established their proving grounds for high-speed IPv6 network and its typical application technologies.
China falls behind many countries in the area of the traditional Internet. To seize the initiative in the NGI and the future information technology is a goal of China, which is imperative and has strategic importance. At the same time, the research and establishment of the IPv6-based NGI is an important guarantee to push forward the informationization process of China. Under such circumstances, CNGI, a national project of China, was launched in 2003. It was initiated by eight ministries and commissions of China, including National Development and Reform Commission, Ministry of Information Industry, Ministry of Science and Technology, Chinese Academy of Engineering, National Natural Science Foundation and Ministry of Education. The program was approved by the State Council of China.
The CNGI is composed of the backbone network, the domestic and Internet Exchange (IX) and the
access network/ Customer Premises Network (CPN).
Based on the existing high-speed optical transmission network, the CNGI backbone network is an IPv6-based backbone network with a transmission rate of 2.5 Gb/s to 10 Gb/s and connects distributed nodes in major cities of China. It is established by the China Education and Research Network (CERNET) center, China Telecom, China Unicom, China Netcom, Chinese Academy of Sciences, China Mobile and China Railcom. The backbone network has core nodes (GigaPoP) in main cities of China. Each node supports access of the network at rates of 1 Gb/s to 10 Gb/s.
IX of the CNGI is mainly used to interconnect to other IPv6 backbone networks at the minimum rate of 2.5 G. In addition, it implements the interconnection with the NGIs in North America, Europe and Japan at the rates of 45 Mb/s to 155 Mb/s on the basis of the interconnection between the existing IXes and the international NGI.
The CNGI project contractors will take charge of the design and establishment of customer access networks/CPNs respectively, according to the actual situation of their own networks.
The established backbone network of the CNGI will become an open proving ground for the research and development of the NGI and its applications in China. It will also become important infrastructural facilities for China to study the NGI technologies, to develop major applications, to push the NGN industry forward. The backbone network centers have the capabilities to operate and manage the backbone networks, to offer diversified services and to support varsious applications.
3 ZTE´s Solution to CNGI
Facing the great opportunity and challenge the CNGi brings, ZTE Corporation takes an active part in relevant technology and product development, and positively participates in the CNGI project. In 2002, ZTE undertook the development of the high-performance routing platform for china´s "863" project, and successfully closed the project. Based on it, ZTE has successfully integrated all the IPv6 functions into ZXROS, its data product operation system platform. With ZXROS, all series of routers and switches of ZTE have been able to support IPv6/IPv4. Moreover, ZXROS may implement the technologies for smooth migration from IPv4 to IPv6, such as the dual stack, tunneling mechanisms (the manual tunneling, tunnel broker and 6to4 tunneling), transition mechanisms based on the Multiple Protocol Label Switching (MPLS) such as IPv6 Provider Edge Router (6PE), and transition mechanisms based on the protocol conversion such as Network Address Translation-Protocol Translation (NAT-PT). Therefore, ZXR10, the router and switch series of ZTE, helps make a perfect solution to the IPv4/IPv6 network. The ZXR10-based solution to CNGI is elaborated here.
(1) Solution to the Backbone Network
Figure 1 illustrates the networking of the CNGI backbone network with ZTE´s ZXR10 router and switch series. All the backbone nodes are configured with hot standby (such as using ZXR10 T1200 and ZXR10 T128). They, together with high-end Ethernet switch (such as ZXR10 T160G/64G series), implement the switching of the local nodes and interconnection with the backbone network. ZXR10 high-end router and switch series is designed to support ultra-large capacity, which can offer the 10 G Pocket over SONET/SDH (POS) and 10 GE interfaces. It also supports the IPv4 and IPv6 dual protocol stack, as well as all the relevant migration technologies, such as the manual tunneling, auto tunneling, 6to4 tunneling and NAT-PT implemented by hardware. Moreover, they support the IPv6 static routing, and such dynamic routing protocols as BGP4/BGP4+, RIPng, OSPFv3 and IS-ISv6. Therefore, ZXR10 may fully meet the network demands of the core nodes of the CNGI backbone network.
(2) Solution to IX
ZTE´s solution to IX of CNGI is shown in Figure 2. High reliability is an important factor in the networking design of IX to ensure its reliable operation, especially the reliability of the core switching. Two ZXR10 T160G, ZTE´s 10 G routing switches, are used to do backup exchange and connection, as shown in Figure 2. The ZXR10 T160G is highly reliable, and supports Virtual Router Redundancy Protocol (VRRP), Signaling Transfer Point (STP) and Link Aggregation Control Protocol (LACP). Besides, its key parts such as the main controller and power support redundancy configuration. Therefore, ZXR10 T160G further boosts the reliability of the system. Operators´ CNGI backbone networks and 6bone centers are connected to IX of the CNGI via ZTE´s Internet routers ZXR10 T1200 and ZXR10 T128. These routers have good scalability, and support diversified interfaces including 10 G POS, 2.5 G POS, 10 GE, and GE. They also fully support MPLS and MPLS Virtual Private Network (VPN), as well as strategic routing, load share and flow statistics. The Router Server (RS) is responsible for collecting routing information of every Service Provider (SP), processing the information according to the routing strategy of the SP, and finally sending the processed routing information to every SP route. The RS uses the Border Gateway Protocol 4+ (BGP4+) as the inter-domain routing protocol, implementing the routing exchange with the SP routers connected to the Network Access Point (NAP).
(3) Solution to IPv6 CPN
ZTE´s solution to the CNGI CPN is briefly illustrated in Figure 3. If the IPv6 CPN or access network is directly connected to the IPv6 backbone network, just as the ordinary access of the IPv4 CPN, the access of Local Area Network (LAN) users may be implemented by either IPv6-supported Ethernet convergence or access to the Ethernet switch (such as ZXR10 3906 and ZXR10 3928), while the access of the Digital Subscriber Line (DSL) subscribers implemented by IPv6-supported DSLAN. When it is necessary for the IPv6 CPN to traverse the IPv4 network to access the CNGI backbone network, a dual stack router (such as ZXR10 GER and ZXR10 GAR) is employed, and IPv6 packets access the CNGI backbone network through the tunnel in the IPv4 network. ZTE´s ZXR10 series fully supports IPv6 and meets the access requirements of the IPv6 CPN.
(4) Solution to Transition from Existing IPv4 Network to IPv6 Network
As a supplement to the solutions mentioned above, the solution to transition from existing IPv4 networks to IPv6 networks is briefly introduced. The basic idea is that the existing network equipment is upgraded to support dual stack. In addition, new equipment (such as ZXR10 T1200, T128 and T64E) will be introduced into the core nodes to support IPv6 if the existing equipment fails to support IPv4/IPv6 dual stack. In this way, the existing IPv4 implements its interconnection with the pure IPv6 backbone networks such as CNGI. At the edge of the metropolitan network, dual stack equipment (such as ZXR10 T64E, GER and GAR) is deployed for the access of IPv6 users.
ZTE, as one of the China´s largest telecommunications manufactures, has invested heavily in the research of IPv6. Much attention has been put to IPv6 since it started the design of IPv4 routers in 1999. It has been energetically carried out the pre-research and industrialization of IPv6 technology since 2000. Its IPv4/IPv6 dual stack router was firstly exhibited at the IPv6 Summit Forum in 2003. In August 2004, ZTE passed the complete certification test named IPv6 Ready that was sponsored by BII, the only test certification institute in China appointed by the IPv6 Forum. ZTE, therefore, became the first equipment vendor to have passed the certification test in china. This was a milestone of the commercialization course of IPv6 technology in china, and indicates that China has become a leading country in the whole IPv6 technologies and their research and development.
ZTE has faith, with its competence, in playing an active and important role in the construction of CNGI, growing together with the development of NGI.
Manuscript received: 2005-06-03
Today IPv6 is the hottest topic worldwide. Many countries are positively impelling the research and application of the Next Generation Internet (NGI). China launched a large scale IPv6 backbone network project: China Next Generation Internet (CNGI). This article introduces the birth of IPv6 and CNGI, then discusses ZTE´s solution to CNGI in detail.