[CentOS] Two Internet connections...

[Timothy Selivanow]

On Wed, 2008-03-26 at 13:27 -0600, Frank Cox wrote:
> I do some occasional tech work for a cable TV/Internet service provider.  They
> have now offered me free services, including cable Internet.  I currently have a
> DSL service through the telephone company and, for several reasons including the
> fact that it is really unlimited service with no cap and it comes with newsgroup
> access (neither of which the cable service has), I'm not really prepared to
> give that up.
> 
> However, since I can get a free cable Internet service too I would like to be
> able to put that to use.
> 
> Does anyone have any good ideas for what to do with an extra cable Internet
> service?  Is there, say, a way to somehow "shotgun" two Internet services like
> you used to be able to do with dial-up modems to increase your transmission
> speed?


The only way that you would be able to use them is a semi-load-balancing
formation.  What I mean by "semi" is that all traffic that exits one
interface will always return to that one.  Also, an entire transaction
will go over only one of the lines, meaning you will only get the
throughput of one line at a time.

The only way to "shotgun" (an ISP had to specifically support modem
shotgunning in the olden days, BTW), i.e. do aggregate routing, is if
you had a separate routed sub-net and ran BGP on the router connected to
the two lines (The rest of the internet has to know that you have two
lines and both are available to use, concurrently).  Needless to say,
this can be complicated, and is not considered a "consumer" setup (most
providers will require it to be some sort of business type connection
like, T and OC connections, which can be on the order of thousands a
month, hundreds for a "fractional" T connection).

If the the first is acceptable, there are a number of docs like
<http://www.samag.com/documents/s=1824/sam0201h/0201h.htm> that would
help (I just did a google search for "balance two internet connections
linux", first link) and guides that set up a redundant line also should
help (it is actually what you are doing, but actively using the
"redundant" line also).  I hope that addresses what you are asking
about.


--Tim
 ______________________________ 
< I'm definitely not in Omaha! >
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