Figure 4 is my own photo of the WRT120N's main board, which I took because the FCC ID photos didn't let me see all the components. Where Belkin went with Ralink for its N150 router, Cisco has tapped Atheros and produced the first product that I have seen using their Align single-stream chipset.
Figure 4: WRT120N Main board
Specifically, the large chip is an AR7240 network processor SoC which includes a 5-port 10/100 Ethernet switch. Its MIPS32 24K processor core is clocked at 400 MHz and has a 16 bit DDR2 memory interface.
The smaller device surrounded by a solder footprint for an RF shield that apparently wasn't needed is an AR9285 single-stream N MAC/BB/radio. 2 MB of flash and 32 MB of RAM finish up the design.
You might notice that even though the radio has a single transmit channel, there are two antennas. When I asked Atheros about this, they said the dual antennas are used to support antenna diversity for receive, just like most 802.11b/g products.
The 120N implements the standard Linksys router feature set that includes:
- DHCP, Static, PPPoE, PPTP, L2TP, Telstra Cable WAN types
- Built-in Dynamic DNS clients for TZO and DynDNS
- Static and dynamic routing
- SPI firewall disable, multicast, WAN ping and IDENT filtering and Proxy, Java, ActiveX and Cooking blocking
- IPsec, PPTP and L2TP VPN passthrough (enabled by default)
- Single port forwarding and Port Range forwarding and triggered ports
- HTTPS admin access, remote management (HTTP / HTTPS) enable with IP range restriction and port setting
- Logging with support for Linksys Logviewer recording
- Access Restrictions with 10 deny or allow-based policies, each with its own list of clients and day/time schedule
- Uplink (LAN to WAN) only QoS with High, Medium, Normal or Low Priority that can be applied to specific applications (divided into Application, Online Game and Voice Device groups), physical switch ports or specific MAC addresses.
- WMM (Wireless MultiMedia) (enabled by default)
I tested routing performance using our standard router tests. All tests were done with the client in DMZ. The results are summarized in Table 1 below.
|WAN - LAN||
|LAN - WAN||
|Maximum Simultaneous Connections||160|
Table 1: Routing performance summary
The IxChariot composite plot in Figure 5 shows nice steady routing, that makes pretty good use of the 10/100 Mbps WAN and switched LAN ports with 92 - 94 Mbps in each direction. Simultaneous throughput is a bit over 150 Mbps, showing that the Atheros AR7240 SoC has enough poop to handle Gigabit ports.
Figure 5: WRT120N routing performance
Try as I might, however, I couldn't get the router to max out the Simultaneous Connection test and only managed to get 160 connections.