Re: Using Two ADSL Internet Connections Simultaneously

Dec 18, 2005 0 Replies


snipped-for-privacy@host122.r-b>>> - NAT in use, and load balancing on a per-connection basis. This


>>> automatically balances the return traffic as well, as everyone on
>>> the net thinks you're actually two separate independent IP nodes.
>> NO, it does _Not_. You cannot change the NAT translation _during_ a
>> 'session' (a single TCP connection). And if the 'incoming' data
>> characteristics change radically _during_ that session, the 'balance'
>> goes out the window.
> What part of "per-connection" was unclear?

Do you note that the above problem identification specifies a *single*


*connection*? What part of "single connection" is unclear to you?

Do you understand that 'per connection' balancing does not work when: 1) the characteristics of the traffic are _unknown_ at the time of connection initiation, and 2) the characteristics of the traffic *change* _during_ that single connection.


The rest of the problem description that you chose not to quote gave a concrete example of the problem -- using a first user with a streaming audio stream, and a bunch of other people then doing something as simple as having multiple HTTP requests ("keepalive" protocol option) over a *single* connection. If you don't like that, consider 'passive' FTP -- where where a number of users first pull a small 'readme' file, and then (still within the _same_ connection), a multi-megabyte binary.


Without 'co-operation' from the other end of the links, the 'per-connection' approach _is_ the 'best' you can do. And in the average case, it does work FAIRLY well. In pathological cases, however, it can degrade to barely more than the capacity of -one- circuit. Those pathological cases are relatively rare, but they


*do*exist*. And, when you get into one, performance gets =really= poor, for comparatively _long_ times.

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