Re: [LARTC] Problem with Load Balancing

[Alessandro Ren <alessandro.ren@opservices.com.br>]

    The second connections will problably gets routed though the same 
link because of route cache I think.

    []s.

William T Mullaney wrote:
>
> Well, if you had a download manager and the system at the other side 
> allowed you to start your transfers in the middle of the file (which 
> isn't out of the question) that could potentially work.  The problem 
> is that as far as I see, there's nothing to force the second 
> connection onto the second line.  It's been kind of a crap shoot of 
> what line gets more information.  In theory you could start the first 
> download stream (and it's routed to ISP A), then perhaps your email 
> client goes out to check your POP account, so that goes over ISP B.  
> The next connection, the second stream, now goes out over ISP B 
> again.  Honestly I don't know exactly how the equalize command for ip 
> route works, though I would think it says to always use the "less 
> used" connection (perhaps on PPS, BPS, % use, whatever, on a per 
> second, 30 second, minute average?), but in my experience that and the 
> weight options don't ever get you exactly 50/50 (or whatever you 
> specify) traffic. 
>
> Things like bit torrent would probably perform better because there 
> are (possibly) many streams for each file, as would having 50 people 
> downloading files vs one.  It seems to be just like rolling dice, if 
> you only roll twice you might get two evens or two odds, but if you 
> roll tons of times, you should tend to get a more even distribution.
>
> -Will
>
> -----Original Message-----
> From: Raj Mathur [mailto:raju@linux-delhi.org]
> Sent: Sunday, September 24, 2006 2:49 PM
> To: lartc@mailman.ds9a.nl
> Subject: RE: [LARTC] Problem with Load Balancing
>
> >>>>> "William" = William T Mullaney <William> writes:
>
>     William> To my knowledge, there is no way to download one file
>     William> from two different connections connected to two different
>     William> ISPs at the same time.  If you are running BGP then you
>     William> might be able to load balance across the two links, but
>     William> that would require your upstream providers to allow you
>     William> to use it, and possibly the purchase of a public AS
>     William> number an IP address space depending on the setup.  If
>     William> you are doing NAT past this link (IE both of your lines
>     William> go two the same ISP and same address blocks, but they
>     William> want to give you 2x 10mb links for 20mb total), then you
>     William> can look at doing load balancing on layer 2 (Fast
>     William> EtherChannel, bonding, Link Aggregate Groups, whatever),
>     William> or creating 2 PPP style links between the computers and
>     William> using a routing protocol like OSPF, EIGRP (but not on
>     William> Linux) or something.  I believe OSPF does equal cost load
>     William> balancing, BGP and EIGRP can, I think, do unequal cost
>     William> load balancing.  But either way, I don't think that's the
>     William> solution in your case.
>
>     William> The only other option I can think of would be some sort
>     William> of software that sends every other packet to a different
>     William> IP or something, which would need to run at the end you
>     William> are downloading at or maybe at your ISPs, but I can't
>     William> think of anything like that.
>
> Wouldn't some download manager software that splits the file up into 
> multiple simultaneous downloads do the trick?  Agreed, not a single 
> download across multiple ISPs, but definitely a single file across 
> multiple ISPs.
>
> Regards,
>
> -- Raju
> -- 
> Raj Mathur                raju@kandalaya.org      http://kandalaya.org/
>        GPG: 78D4 FC67 367F 40E2 0DD5  0FEF C968 D0EF CC68 D17F
>                       It is the mind that moves 
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