Hands-on hardware: DSL / cable modem routers
You've got your DSL connection. You're using an ISP-provided DSL bridge (aka DSL
modem). Your LAN is routed through one computer that accesses the Internet with network
address translation (NAT) or proxy services. Your service is OK, but you feel there are
definitely some weak spots.
Where are the weaknesses?
The most obvious weakness is that Internet access depends on one computer. If that
computer is a server, it's probably up and running most of the time; but then you-know-
what happens, maintenance is required, and so on. And, of course, such things will
happen at the worst possible moment for someone on the network.
Another weakness is that the computer serving as the router/NAT runs at least four
pieces of software that consume resources: DHCP, NAT/Proxy, the Point to Point Protocol
Over Ethernet (PPPoE) service, and the DSL connection software. All are OK, but
consume valuable resources.
Also, your DSL probably goes down more often than you'd like. When this happens,
the software establishing the connection to the DSL must continually retry the
connection -- or, more likely, try a few times, then give up until an administrator
instructs it to try again. We were offline for 6-8 hours last week because no one
restarted the DSL connection. The actual outage was probably much shorter.
Where do you go for improvements? For a minimal investment ($80-$150, depending on
brand), you can add a DSL/cable modem router, a semi-intelligent box that sits between
the DSL bridge and the LAN. A router is smart enough to continually retry the DSL
connection after it goes down. It can also provide some valuable services to your LAN
and lighten your server's workload.
Thanks to several vendors, I was able to try three different routers: a Hawking
Technology PN9225 10/100 Broadband DSL/Cable Router, a Trendware TW100-W1CA, and a
Linksys BFSR11.
Feature Comparison: Three DSL/Cable Modem Routers |
|||
| Hawking PN9225 |
TrendWare TW100-W1AC |
Linksys BEFSR11 |
|
| Default IP | 192.168.10.10 | 192.168.0.1 | 192.168.1.1 |
| Switchable Xover | No | No | Yes |
| Reset button | Yes | No | Yes |
| DHCP | 253/Fixed & Dynamic |
128/Dynamic | 253/Dynamic |
| DNS | No | No | No |
| PAT | 10 TCP/4 UDP | Unspecified | 10 |
| DMZ support | Yes | No | Yes |
| Serial Port | No | Yes | No |
| Telnet | Yes | Yes (port 333) | No |
| Browser | Yes | No | Yes |
| Dedicated GUI | Yes | Yes | Yes |
| Configuration | Use browser | Use GUI | Use browser |
Each of those devices connects in the same way: a category 5 network cable goes from
the DSL bridge to the router, and another cable goes from the router to the hub or
switch. As with other devices of this nature, you sometimes need a crossover cable,
sometimes a straight-through variety. Some setup is required for each, and depending
on the capabilities you choose to use, some networking skills may be handy. The Linksys
has a nice feature: a switch that changes the LAN port from MDI to MDIX, so you can use
either type of cable.
All three devices
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