Mindhive

Networking Part 2: Edimax BR-6524

Well, as I'd mentioned before, Earthlink pissed me off to the point where I ordered Adelphia cable. However, rather than cancel EarthScum, I decided to figure out some way to use load-balancing, in order to combine the two connections into one uber-connection -- as suggested by Roger and this thread on dslreports. At first, I wanted to roll my own box -- but then I scrounged around, and realized that the missing spare parts (3 NICs, a decent CPU, hard drive) would cost me as much as a dedicated device, so I decided to try out the Edimax BR-6524 router instead of messing with Linux kernels. Yes yes, you can all stop snickering now. Knowing me, you can probably guess what the end result was, but I'll tell you anyway.

Background

First, a few words about my network setup. In the past, I had a single Earthlink internet connection going into an ironclad (literally !) Netgear router, and being split off to several other computers, as you can see on the diagram below.

There's not really a need for the hub from the design point of view, but it makes the wiring easier, so it's there. Also, I actually have about 6-7 computers on the network, but I was too lazy to draw them all. What I wanted to do is change my configuration as follows (changes shown in green):

Sounds easy, right ? If only.

Router

The marketing page for the Edimax router reads like it was written just for me: "Aggregate Bandwidth... Mix DSL and Cable... Load balancing based on the WANs' speed... Firewall... NAT". Unfortunately, there were some comments on that dslreports thread about a different router, which did not work with Earthlink due to some kind of weird-ass PPPoE configuration problem. Naturally, I called Edimax's tech support line to make sure the router will work. Edimax's people were really nice: they admitted that they did not know whether this router will have problems with Earthlink; so they knocked the price down a bit, and offered to pay for shipping both ways if I couldn't get it to work. After talking to EarthScum, I couldn't help but marvel at how actually helpful and honest Edimax's tech support people were. Anyway, this seemed like a good deal, so I ordered the router.

Massive Problems

I actually did get the router to work with both Earthlink and Adelphia without any trouble. Unfortunately, there was trouble with every other aspect of it.

• First of all, I discovered that if I plugged more than two wires into the router's LAN ports, it developed a weird hiccuping behavior: it would shut down all LAN connections every couple of seconds (lights off, "network cable unplugged" in Windows), and then it would immediately turn them back on. This problem went away if I just connected a single computer to the router; it also went away when I dusted off my Netgear switch and plugged it into the router, and connected the rest of my network to the switch, as shown below.

  

  I upgraded the router to the latest firmware, but that didn't do anything except displaying some prettier icons in its Web UI (incidentally, the router's default IP is 192.168.2.1, in case you're lazy like me and don't RTFM).

• Unfortunately, I also had another weird problem: sometimes, when a new computer would come on the network (through the router's built-in DHCP), every other computer would get an "IP Conflict Detected" message from Windows. Punching the usual ipconfig /relelease ipconfig /renew deal fixes this, but you have to admit that this is pretty annoying. What's worse, this failure was intermittent -- I have no idea what precisely triggers it.

• This was not the only annoying intermittent failure. When I left a machine idle for a while (such as overnight, or overday rather, heh), it would lose connection to the Internet for some weird reason. I.e., I could ping the router, but I could not ping google or yahoo or whatever. Disturbingly, ipconfig /release ipconfig /renew did not solve this problem; only the actual rebooting solved it -- until next time. If the computer was left not idle, but pinging google in a loop, this problem never showed up. I set the router's DHCP lease to "forever", so that shouldn't be a problem.

• I also noticed that the router would sometimes just knock me off the Internet for no reason (it happened as I was typing this post, for example). My connection would immediately come back up, but all the downloads I had in progress would of course stop. Again, this is an intermittent failure that I don't know how to trigger on purpose.

All these problems occurred on most computers on my network; all of these computers are patched with the latest drivers and service packs, and they all have different network cards -- so I think this problem stems from the router itself. Also, I never had this kind of trouble with the Netgear.

Load Imbalancing

Another problem I had was with the router's load balancing. The tech support people and Edimax's marketing assured me that the load-balancing is supposed to be session-based. I.e., if I star downloading a large file from a fast server, and then then open up another download on the same machine, the router is supposed to automatically assign a different WAN port to the new download. This would, of course, utilize both DSL and Cable lines in parallel, for a whopping 3Mb download speed. Unfortunately, in reality, the router's load balancing didn't work at all -- or, at best, it was machine-based. That is to say, the router would assign one line (Cable or DSL) to a specific computer, and all downloads from that computer would go over that one line, regardless of how saturated it was, as this screenshot shows:

Needless to say, this is a bit less than optimal. Note that the failover capabilities of the router did work: when I'd disconnect one of the WAN lines, the router would immediately switch to using the other line, with no problems. Interestingly enough, the router has an option where I could permanently assign a specific WAN line to a given local IP; this would defeat the purpose of load-balancing, but it would at least allow me to manually distribute the load. Unfortunately, this feature also worked only intermittently.

SMTP

This was not really a problem with the router, but more of a missing feature. It turns out that both Earthlink and Adelphia disallow access to their SMTP servers from outside their respective networks. That is, if I tried to send mail through mail.earthlink.net while connected to Adelphia, I would get denied. This makes sense from the anti-spammer security point of view, but I think you can see how it would cause problems in my case, when I have both Earthlink and Adelphia connections, assigned (at least in theory) randomly to each session. I tried to figure out a way to program the router to always route traffic on port 25 to WAN2 (the Earthlink line); unfortunately, I could not figure out how to do it. A call to Edimax's tech support confirmed that in fact this is impossible.

Conclusion

Naturally, I called Edimax's tech support about all these problems, and asked them for help. After talking to EarthTrash, this was like a breath of fresh air: instant response, knowledgeable techs who actively try to solve your problem as opposed to making you disconnect your coffee maker for no reason... Ah, yes. Unfortunately, in the end, Edimax could not actually help me with any of these troubles. Part of the problem here is that Edimax's US office is just a front; the actual engineers are all in Taiwan, and talking to them personally is not really possible. So, now I've pretty much hit a dead end. Currently, I am thinking of returning the Edimax and trying some other solution (after I try a few other things like static LAN IPs); this router is great on paper but it did not work at all for me. If someone knows how to fix at least some of these problems, please let me know. And, as always, stay tuned to this blog for more frustrating networking news.

Posted by metabug at 2004/04/30 18:21 | TrackBack (0) | Categories: Articles