Wireless LAN and ADSL combined access technology

With the continuous development of broadband applications, ADSL increasingly popular, at the same time, with the advent of wireless LAN technology and development, this market is also rapidly heating up, but the absolute number still less than ADSL.

There are already technologies and products that combine the two, and the advent of these technologies will greatly accelerate the popularity of WLANs.

In the traditional WLAN access, AP as the access point, AP and wireless network card to 802. One (A, b or G) for standard communication, the role of AP only as a "Wireless LAN to LAN" Transparent bridge, can only play the role of user access to the local area network, its own and no routing function, the need for additional WAN routers to connect users to the Internet. Therefore, the main application in the enterprise intranet.

The traditional AP generally does not lead the way by function, completely a pure two-layer device, along with the needs of home and Soho office, leading the way by the function of AP appears. Lead the way by the function of AP not only can realize WLAN access, but also provide WAN interface, with IP three-layer Routing and Network address translation NAT and other functions, through Adsl/modem/fttb+lan and other technologies to access the Internet. Not only this, some products can also provide 4-port Ethernet switch and print interface (as a print server), and some high-end devices can also integrate the VPN function, so in cost than the "ap+ router" network cost significantly lower, the network structure is relatively simple, suitable for small network or home network.

The AP router with ADSL interface is developed on the basis of the AP, and its WAN interface is fixed ADSL, which is more economical and more convenient to manage than the way by the AP plus ADSL modem of the function, and thus realizes the combination of Adsl+wlan.

AP Router system with ADSL interface, mainly consists of four parts: network processor, to achieve the distribution of data packets, media conversion, routing/nat, System control functions; ADSL part, responsible for ADSL line transceiver, DMT modulation and other functions; wireless part, responsible for the modulation, transmission and reception of wireless signals Ethernet Swap part, responsible for Ethernet switching. At present, the main components of the chip program includes the following: Network processor, ADSL codec, wireless parts, Ethernet and other parts. The main functions of AP router with ADSL interface are as follows: ADSL codec, accord with G. DMT (G. 922. 1), G. Lite (G. 922. 2) and other standards, ATM functions, can achieve multi-protocol encapsulation, such as rfc1483/2684 Bridge, Rfc1577ipoa, RFC2364PPPOA, Rfc2516pppoe built-in dial-up and other packaging methods, wireless codec, in line with the IEEE802. 11 series Standard, currently mainly to support 802. 11b is the main, the future can support IEEE802. 11g Standard, support WEP encryption; Ethernet switch can realize Ethernet switching, realize simultaneous access of multiple PCs, IP Routing and switching functions, provide Ethernet switching, IP routing, NAT address translation, DMZ,DHCP address assignment, Mac filter/IP filtering, etc. management functions, Support for Web management and SNMP Simple network management protocols.

In the home type access, the AP router with ADSL interface can be considered as the home gateway, so that multiple PCs in the home are connected to the Internet at the same time. In the actual business development, can be "Tianyi" and other wireless services and ADSL bundled sales, thus speeding up the development of wireless WLAN business speed. There are generally two ways to do this in the actual configuration.

Single PPPoE session. User home multiple PCs (through a wired network card or wireless network card connection), through DHCP dynamic access to IP address, gateway, DNS and other parameters, AP router configured as built-in PP? Poe dial-up Access, the user can access the Internet via the NAT address translation feature provided by the AP router. In this way, the user's IP address is private IP, for some special applications, such as bi-directional video application after the NAT conversion may have some problems, generally through the configuration of port mapping or DMZ implementation.

Multiple PPPoE sessions. AP router directly configured to bridge the way, the internal number of users can be Pcpppoe dial-up access to IP address, each user can obtain a public network IP address. This approach to the lack of NAT conversion, so for a variety of network applications do not exist NAT penetration problem, but also for telecommunications operators to maintain a relatively simple, the disadvantage is that users to occupy multiple IP, the demand for IP address will be increased to bras (Broadband access server), The requirements of the RADIUS certification billing system are also relatively high.

For public hotspots (hotpot), ADSL can be considered as a remote access means. Compared with traditional line access and optical fiber access, it can save construction expenditure and speed up the distribution of WLAN hotspots.