One bad thing i’ve found on hardware level3 multi-wan routers, is the lack of polyvalence to setup the link down state detection.
Some routers only watch for PPPOE session state. This is clearly not a good method for broken link detection, because the PPPOE session can be ok, but routing on next routers down.
On a good multi-wan router, i think that there should be at least those possibilities for broken link detection :
– pppoe state detection
– ping detection to a known target
– http / ftp connectivity test to a known target
– SIP / IAX2 connectivity tests, and more generally a possibility to define custom scripts to detect the liveness of a specific target.
The second important thing, is certainly to be able to shape each class of traffic, load balanced it, or not, define a primary link and backup links for each traffic, etc…
I think that it is very important to have a good failover support, more than a full options load balancing support. Load balancing only works for session oriented traffic, and even with this traffic it is sometimes necessary to lock it on a specific WAN link.
To support multilink with connection oriented protocols, like VoIP, we need link agregation instead of load balancing ; like for example MLPPP. This is clearly not possible without support from the ISP.
Inbound shaping is important as well, unfortunately with Linux it is only possible to do it by paquet drop, to my knowledge.
For TCP traffic, it would be more adequat to shape the inbound traffic by manipulating the TCP window.
The third thing is perhaps multi IP support for wan, and explode it on multiple NAT network on different VLANs, or bridge specific IP addresses directly to a specific host.
If you need some interesting informations about GUI interfaces for multiwan routers, instead of reinventing the well, you could download the manuals of PepLink, Draytek, Edimax (level2 multiwan), Xincom. They are the most interesting products i’ve found. Edimax is special because they are level2 (expensive) multi-wan routers. They do work with all protocols and can do things that a level3 multiwan router cannot do.
I’ve found the Draytek Vigor 3300 GUI quite interesting and powerfull. I advice you to download the manual and take the good GUI ideas.
Last, in the hardware multi-wan router area, IPv6 is non existent, except on Cisco products…
A good function is to be able to bridge IPv6 coming from a dual protocol PPPOE session to the LAN side so that we can have IPv6 even if we don’ t have advanced control on it. This is a first stage to experiment with it. Perhaps just adding RADVD to announce the IPv6 network prefix to the workstations.
I have the chance to have an IPv4 / IPv6 PPPOE ADSL connection here, so i can test this.
There is a no mans land with IPv6 on GUI interfaces. Strange… Ipv6 is not so complicated, and simplify the administrator work, for example to connect large IP cameras networks.
There are toons of very complicated and efficient software on Linux, like OpenVPN. I can’t explain why there is such a big hole and lack of documentations with QOS and Multi-Wan.
Projects like ZeroShell are very profitable to the Opensource community.