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Push vs pull vs hybrid, was: Re: [RRG] Mobility considerations in proposal evaluation



On 26 feb 2008, at 18:34, Tony Li wrote:

On the mapping area, we have push systems and pull systems. Both have substantial drawbacks. Are there better hybrids? Are there alternatives?

I think a general model is:

A) you push the information a > 0 part of the way
B) you send the packets a >= 0 part of the way
C) you pull the information a >= 0 part of the way

Fill in the values for A, B and C to your liking, considering that:

- there is a limit to how much and how often you can push
- pulling incurs delays for first packets and other caching issues
- there is very little effective admission control in a distributed system so hard to limit growth
- too much pulling is really an inefficient way of pushing
- moving packets without specific routing info increases distance traveled, reducing performance and increasing banwdith use

If so inclined, do the above for mapping relationships and for reachability separately, rather than making one system that handles both, considering that:

* you can guess reachability and be right often, not so much for mapping
* reacting slowly to reachability changes reduces service level a lot
* reacting slowly to mapping changes doesn't automatically reduce service level

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