In-depth exploration of the internal structure of standard wireless router WNR854T

With the development of China's routing industry, wireless routers are also widely used. Here we mainly introduce the internal structure of the standard wireless router WNR854T. As the triple-play (triple-play) concept in the telecom industry gradually becomes a reality, wireless hubs have become increasingly important. At the same time, the traditional Wi-Fi 802.11b/g solution is insufficient for the increasing amount of data in the consumption environment.

However, through 802.11n (still in draft form) and its proprietary extensions, it is possible to establish a full wireless environment, this allows users to surf the Internet, chat over VoIP, and watch IP TVs through a single cable. The WNR854T of Netgear is a wireless router that complies with the draft 802.11n standard. It is later compatible with 802.11b/g and can provide a wireless connection rate of up to Mbps. Of course, in fact, this value is limited by the network environment and the compatible devices used to connect the two ends of the link. In a word, although the theoretical bandwidth is very attractive, the actual available bandwidth may only be half of the theoretical bandwidth. Even so, the high speed without high security is futile, so WNR854T has designed a complete firewall (NAT, SPI) and access control (WPA, WEP, MAC authentication) to cope with security issues, and even built-in DOS protection and intrusion detection and other security measures.

Implementation of core communication functions

WNR854T implements core communication functions based almost entirely on the chip of Marvell, which uses the company's Top Dog multi-input multi-output (MIMO) technology. The MIMO technology uses a 2 × 3 topology to implement two transmission channels, three receiving channels, and multiple antenna diversity modes. From the appearance of other competing products, we often see some weird antenna arrays. The difference is that WNR854T uses an exquisite white chassis, all the circuits are sealed in this simple box.

All of its electronic components are distributed in two surface mount components. One is the basic networking and wireless router motherboard for wired lines and control, and the other is responsible for all wireless router connection functions. On a large motherboard, the key part is an 8-port Gigabit Switch-Marvell 88E6131, which is responsible for the selection of four hard-wired Ethernet ports on the broadband connection and WNR854T backplane. In addition, there are two Marvell transceivers on the motherboard that form a four-port wired Ethernet distribution array of Ports 1 and 2.

Marvell 88F5180 provides the wireless router with a processor that connects to the switching chip and wireless data card and may provide all network security functions. The memory required by the 88F5180 processor is composed of Intel's 8 mb nor flash memory (28F640) and two Nanya NT5DS8M16FS ddr sdram chips (32 Mb in total. Marvell even provides switching voltage regulators used in components to implement system power management. The wireless data card mentioned above can be inserted into a 123-pin Side card connector located on the back of 88F5180.

Card insertion means that the same board can be used in other terminal systems, even if these systems may have different connection characteristics around the wireless router 802.11x function. These wireless Nic devices are still mainly from Marvell. The two main chips are baseband/Media Access Controller (88W8361) and 802.11x transceiver (88W8060 ). The 8 MB EtronTech SDRAM that provides baseband/MAC memory needs to be locally connected to the wireless Nic. There is also an Atmel 4kB E2PROM for code storage. In addition, a Marvell switching voltage regulator is often required for local power supply systems.