A detailed explanation of IPV6 NAT444 and Ds-lite transition technology in metropolitan area network

Two key transition technologies of metropolitan Area Network IPv6 transition Technology--nat444 and ds-lite, what are the basic factors to be considered when choosing two kinds of transition technologies? This blog post will give you a detailed description of the rationale for both technical solutions and how to deploy them later.

The large number of broadband users in the metropolitan area Network is the main force that consumes the network IPV4 address. Facing the exhaustion of the IPv4 address, one of the measures that can be taken is to slow down the consumption rate of IPv4 address, to change the way that users enjoy a IPv4 address, to share a IPV4 address through NAT technology, and to develop IPV6 application, and to attract users to IPV6 network, Reduce the consumption of IPv4, and the latter involved in IPV6 terminals, business, operations, network and other industrial chain of collective linkage, in recent years, although the rapid development has been achieved, but relatively large IPv4 group is very small, therefore, to slow down the IPV4 address consumption speed, has become the current network builders the primary task.

In the process of IPv6 transition, Nat444+ds and Ds-lite are the most discussed technical solutions in the metropolitan area network.

Nat444+ds Technology: For IPV4 business, through the two-level NAT44 implementation of the load, the first level NAT44 in the home network CPE side, the realization of user private IPV4 address to the operation of private IPv4 address mapping, the pattern is 1:1 mapping, the second level NAT44 is in the network LSN ( Large sacle NAT), to achieve the operation of private IPV4 address to the public network IPV4 address mapping, the pattern is n:1 mapping. For IPV6 Services, the End-to-end IPV6 protocol stack is used for hosting.

Ds-lite technology: For the IPV4 business, through the Ipv4-in-ipv6 tunnel combined with NAT44 to achieve the load, home network CPE as a B4 equipment, to achieve the private network IPV4 Business Tunnel Package/solution package, is the end of the Ipv4-in-ipv6 tunnel, As a AFTR device, the network CGN device realizes the solution encapsulation/encapsulation of the tunnel data, and converts the IPV4 address of the private network to the IPV4 address of the public network, and the mode is N:1 mode. For the IPV6 business, it is similar to NAT444, which is hosted by an End-to-end IPV6 protocol stack.

How to choose two kinds of technology according to network situation in metropolitan area Network, and how to choose the way of deployment?

First, it is based on the status of the network analysis.

If the network is to be modified to support only the IPV4 protocol, and the ability to upgrade to Ipv4/ipv6 dual stack, such as the device is obsolete can not support the software upgrade support double stack. In this kind of network foundation to carry on the transformation principle is maintains the current network service, does not introduce the IPV6 demand. At this point NAT444 technology has advantages, should not need to increase the network IPv6 protocol can also be added to the new business "Save IPV4 Address" deployment, and its home network CPE requirements are only NAT44 function, at present all the CPE equipment are supported.

If the network can be modified to support the software upgrade to IPV6, and the upgrade does not affect the existing IPV4 business load. On the basis of this kind of network, the principle of transformation is to develop IPV6 business under the premise of maintaining the current network business. Because the backbone network (mainly refers to the metropolitan area Network SR, BRAS, CR) all have IPv6 ready ability, therefore at the backbone network level all satisfies the nat444+ds and the ds-lite demand. Home Network CPE Equipment because of numerous and different types of capacity, so the transformation of Home network is the main factor affecting the choice of nat444+ds and Ds-lite. Ds-lite needs CPE to support Ipv4/ipv6 dual stack and support Ipv4-in-ipv6 tunnel encapsulation and encapsulation capabilities, the current network of existing CPE is not supported, only the new CPE is available, NAT444 to Tan IPv4 users of the CPE to support the NAT44 function , the current network of CPE are supported, for dual-stack users need to support Ipv4/ipv6 dual stack and NAT44 function, only the new CPE is available. Therefore, NAT444 applicability is more extensive.

If the network is already fully equipped with IPV6 capacity of the new network, Ipv4/ipv6 ability to support very high, including backbone network and home network CPE are supporting the mainstream of the transition technology, at this time the network level are met Nat444+ds and ds-lite requirements, How to select the next level of analysis that needs to be continued.

Secondly, it is based on the carrier of the business and network operation dimension to analyze.

In the business bearing aspect, the Nat444+ds and ds-lite to the IPV6 traffic load is the End-to-end IPv6 protocol bearer, does not have any difference; for the IPv4 business, NAT444 is to IPv4 the message to carry on two times NAT44 the conversion, the message still carries on the IPV4 way, There is no new header, Ds-lite is the IPV4 message to the IPV6 header encapsulation, add a header, which will bring problems such as MTU, and the carrying efficiency will be lower. Therefore, in the business carrying efficiency analysis, NAT444+DS is higher than ds-lite.

In the aspect of network operation and maintenance, Nat444+ds and Ds-lite have put forward the transformation demand to bras, AAA, billing, report, traceability system and so on. For Nat444+ds, the network exists IPV4 and IPv6 two kinds of business flows, so in the business deployment and management need to manage both types of business, if it is for dual-stack users, the corresponding IPV4 business flow and IPv6 Business flow reports are merged. For Ds-lite, for ds-lite users only based on the IPV6 address management, user authentication, billing and management can be unified based on the user IPv6 address, at this point, ds-lite on user management advantages obvious, throughout the network, Network transformation period is IPV4 and IPv6 coexistence, so the deployment of Ds-lite network will still exist IPV4 users, so based on user IPv4 address operation and maintenance system management is still necessary. Therefore, Ds-lite is more advanced in operation and maintenance management, the network superiority is obvious in the network IPv6 degree, but the network in the transformation period still cannot realize the management of IPV6 single stack completely. Nat444+ds in the requirements of the full double stack business management, and the report, traceability and other systems to put forward new requirements.

Furthermore, it is based on the network transformation process to analyze.

The transformation process of the network must be experienced "pure IPV4 network--ipv4/ipv6 double stack and IPv4 occupy the mainstream--ipv4/ipv6 double stack and IPv6 occupy the mainstream--pure IPV6 Network" development course. Nat444+ds and Ds-lite service user main body is the private network double stack user, nat444+ds in the transition to the IPV6 development later time is does to the network does subtraction, subtracts the backbone network the IPV4 function, subtracts the Operation dimension system to the IPV4 user's management and so on; While the IPv4 area of Ds-lite is limited to the domestic network CPE side and CGN side, with the reduction of user IPv4 demand, CPE and CGN reduce the processing demand for the IPV4 business, the backbone network maintains ds-lite single stack function, Network operation and Maintenance will also be carried out by IPV6 User management, the network stability is better.

Therefore, the analysis of the technical advantages and disadvantages of nat444+ds and ds-lite can not be generalized, which needs to be analyzed and selected according to the different network status and requirements.