Consumer-grade dual-homed connectivity options?

Vincent C Jones v.jones at networkingunlimited.com
Mon Jan 4 08:10:05 CST 2010


Most of the SOHO router vendors (Netgear, Linksys, etc) have a model
targeted at this application. When this class of "dual homed" router
first came out several years ago, they were notoriously unreliable, but
I would hope they work better by now. A search on the term "ping based
routing" should give you insight into the current state of affairs,
although it will probably take some work because there is no standard
terminology to describe the facility, and most implementations no longer
rely on "ping" to do the job of detecting link status.

A few limitations to keep in mind:

1 - These routers are targeted at home users, are cheap, and you don't
get what you don't pay for. 

2 - The job can be done using "real" routers (Cisco, Juniper, etc), but
setup requires work and getting a solution that actually works can be
tricky. 

3 - Be wary of any advice that you get from anyone who has not actually
done it on the box in question! There are many ways a solution which
should work will fail miserably. For example, when I looked at this
problem a few years ago for a client, the SOHO routers tended to lock up
and require a power cycle every few days while Cisco IOS routers would
not clear the NAT table when a link failed soft and tended to stop
testing a link once it failed, requiring manual recovery.

Good luck and have fun!
--
Vincent C Jones
Networking Unlimited, Inc.
www.networkingunlimited.com


On Sat, 2010-01-02 at 18:14 -0500, Steven King wrote:
> You would need at least one router for this.
> 
> Personally I would connect both DSL modems into a small Cisco router or
> multi-layer switch. Use that router as the default gateways for each LAN
> and have two static routes as the default gateway on the router to
> specify each DSL line. This would allow for load balancing each connection.
> 
> Although, you run into the issue of needing PAT on both lines. This
> wouldn't be complex, but would need to be handled by the router as well.
> 
> I am not sure about asymmetric paths though. Depending on the device, it
> may handle this differently, and there is no guarantee that the source
> of your traffic will be from the same connection all the time to the
> destination. This would cause connectivity issues. There really is no
> elegant solution to that without having a full routing table of the
> Internet and 2 separate providers. Others on this list may have a
> solution to that issue off the top of their heads, or have done this
> themselves.
> 
> 
> On 1/2/10 5:48 PM, Scott Weeks wrote:
> >
> > --- paul.w.bennett at gmail.com wrote:
> > From: "Paul Bennett" <paul.w.bennett at gmail.com>
> >
> > At home, I currently run two DSL lines. Right now, we just have two  
> > separate LANs, one connected to each line, with my wife's devices attached  
> > to one, and my devices attached to the other. For a while now, I've been  
> > thinking about setting up a load-balancing routing solution to give both  
> > of us access to both lines.
> > ---------------------------------------------------
> >
> >
> > Maybe www.xincom.com/products.php will work?
> >
> > scott
> >
> >   
> 




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