Quidway® NetEngine 40 Series Universal Switching Router Service Boards
Copyright ©2007 Huawei Technologies Co., Ltd. All Rights Reserved.
http://www.huawei.com/products/datacomm/
2
z
NAT Service Board
Network Address Translator (NAT) is a technology for changing the source or destination address
in IP packets. NAT can translate private IP addresses into one or multiple public IP addresses
(unique globally), which effectively solves the problem of public address shortage and realizes
security protection by hiding IP addresses of the internal LAN. Currently, the NAT technology is
widely applied in Internet.
The NE40 is equipped with dedicated NAT service boards that support multiple translation methods
such as NAT, Port Address Translation (PAT) and Nat & Port Address Translation (NPAT). The
dedicated NAT service board delivers a bi-directional gigabit wire-speed address translation
capacity. Each board can support 1,000,000 concurrent connections, process 200,000 new
connections per second and refresh 500,000 NAT table entries per second. Moreover, the NAT
service board provides complete security logs, making it easy to trace illegal operations or improper
operations and thus improving the availability and security of network equipment.
The NE40, as a USR, provides dedicated NAT service boards, mainly applied at the egress of
MANs, enterprise networks and campus networks or in positions of some large-scale MANs and
government networks that have NAT requirements.
z
NAT-PT Service Board
With the rapid development of global mobile and broadband technologies, there is a greater need
of IP addresses in the future. The current IPv4 address storage, however, fails to satisfy the
demand. Therefore, the IPv6 technology should be fully introduced as soon as possible before IPv4
addresses are used up. Nevertheless, IPv6 cannot completely replace IPv6 immediately as it is
impracticable to make all network communication equipment support IPv6 in a short time. And IPv4
will coexist with IPv6 in the network environment for a rather long time and gradually evolve
towards IPv6.
IPv6 provides many transition technologies for this transition process, focusing on interconnection
between isolated IPv6 networks and interconnection between IPv6 and IPv4 networks (enabling
resource access between two different networks). Network Address Translator-Protocol Translator
(NAT-PT) is used to realize interconnection between IPv4 and IPv6 networks.
NAT-PT is a protocol translation technology. Basic idea of this technology is to translate the network
layer protocol header to make it consistent with the protocol type at the peer end and realize
interworking when an IPv6 node communicates with an IPv4 node.
The dedicated NAT-PT service board used in the NE40 implements IPv4-IPv6 protocol translation,
and can be applied in such core networks as IP bearer network and MAN to realize gradual
evolution from IPv4 to IPv6.
