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Re: ADSL multiplexing (bonding)

  • From: Ryan O'Connell
  • Date: Mon Oct 24 06:55:15 2005 
On 24/10/2005 10:22, Gregory Edigarov wrote:


william(at)elan.net wrote:


On Mon, 24 Oct 2005, Gregory Edigarov wrote:
Need an advice on what type of equipment/manufacturer would one use to multiplex 2 or 4 ADSL lines?
E.g we need to get 2 ADSL line to act as one. Something like Etherchanel with Ciscos.
Are all these DSLs parallel to each other from the same device on the
end-site to the same device on the provider side? If not are these at
least DSL lines provided by the same DSL provider with most likely ATM
that originates at DSL provider and end on end-user dsl line site? Are
the DSL lines exactly the same speed and configuration?
Let's think I will answer "yes" to the questions one at a time. :-)
I do not have the formal task description yet, so I am merely looking for opinions on options available,
so I could start making decisions.

Hardware-wise a Cisco 1700 will take two ADSL lines - if you want four lines you're looking at a 2600. I'm sure there are some but I'm not aware pesonally of any other vendors that supply CPE kit capable of handling multiple DSL lines.

Technology-wise, you can either use Multilink PPP or per-packet load balancing. Generally, you'll need the cooperation of the upstream ISP - although you can load balance upstream traffic using per-packet load balancing at your end, the ISP will mostly likely have unicast reverse-path turned on so will drop the packets. Obviously loadbalancing the downstream traffic requires a higher level of cooperation.

Multilink PPP is better as you get lower latency with the right settings plus less problems with out-of-order packets. However, I belive even with Multilink PPP you'll get *some* out of order packets which is quite cappable of totally crippling real-time applications such as VoIP.