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Nexland Pro800Turbo Load Balancing Router Review
An anonymous submitter writes "Found this review today over at OverclockersClub.com. Apparently this router can load balance two broadband connections like DSL, Cable, or T1. The router can also act as a backup feature in case one of the broadband connections goes down, the router will automatically switch to the connection still working." At $400, it's not gruesomely expensive either, and I guess if you're willing to pay for two broadband connections anyway... The spec sheet (PDF) has more information.
Why not a software solution, instead of dropping 400 bucks? Ultra Monkey is a package including LVS, prepared mostly by Horms.
Super Sparrow is a distributed load balancing package also by Horms (formerly of VA Research|Linux|Software|Spacecraft|Doohickeys) that uses BGP route information to decide which server ought to service a request. Neat stuff. Super Sparrow is not ready for deployment, and appears to be on a back burner (due to VA's disinterest in such things these days, probably).
LVS is the project to beat in this space, by a long ways. It is very very solid, and extremely efficient. Wensong is quite an impressive nerd.
The theory of relativity doesn't work right in Arkansas.
You can use NAT to hide the real servers from the Internet if you like. This allows you to use most any web server you like (such as IIS), but more fancy routing tricks can be done with Unix or Linux servers for even better results. We use NAT at our site (university EE department) and it can handle more load than we will ever receive -- our objective is high-availability. Also, you can use different methods for different server clusters on the same director (e.g. tunneling tricks for Linux apache servers, and less magic for IIS).
And LVS can be set up such that once a user connects to a particular server, his subsequent connections go back to the same server.
Useful links:
The theory of relativity doesn't work right in Arkansas.
"If the Duplex LED is flashing this means their has been a collision on your network. This happens when packets are dropped for some reason or the packets have been misdirected. This usually only happens when two computers are using the same IP address and this usually only happens when you specify an IP address rather than using the DHCP feature built in the router."
Network collisions occur when two hosts try to submit simultaneously. The NIC listens for the resulting static on the network line (as static is produced when the signals garble), waits a random length of time, and retransmits. This happens (I believe) at a lower-than-protocol level.
From what I understand, this $400 gizmo is geared towards homes and businesses that mostly surf and download on multiple computers. Unless some black magic is used, no *single* download or upload will exceed the thruput provided by the faster of the two internet connections. It's simply not possible... the router has been assigned two IP addresses from two totally different ISPs that don't know anything about each other. It is similar to a single threaded application running on a dual CPU computer -- the application will only take advantage of one CPU. However, if there are more threads running, they'll be balanced across the two. Same goes for this router. If you have multiple downloads running, they'll be spread across the two internet connections at the router. It may not be the end-all solution, but it sure would be handy for a download-happy household.
To do what you are referring to would require a professional router (Cisco, Juniper, linux box with fancy software, etc) with BGP support and ISP(s) that are willing to help you. To use more than one ISP will require your own IP block assigned from the ARIN (not from your ISP's own block of addresses). Work with both of your ISPs to configure routing tables and away you go. Sprintlink, Worldcom, AT&T, Cable&Wireless are very helpful in configuring such a multihomed setup. Below is a link to some info from Sprintlink:
http://www.sprint.net/faq/bgp.html