Re: [RAM] The mapping problem: rendezvous points?

[Lars Eggert <[e-mail]>]

On 2007-5-9, at 14:20, ext David Conrad wrote:
> On May 9, 2007, at 3:05 PM, Lars Eggert wrote:
>> Don't forget that pretty much all our transport protocols work by  
>> gathering information about the transmission path (RTT, bandwidth,  
>> etc.) by running statistics over the packets they send.
>
> Yes, but you left out the part about those protocols having  
> mechanisms to detect and recover from connectivity degradation  
> (e.g., slow start).

I'm not saying that they will break - I am saying that there is a  
danger of additional inefficiencies.

> However, this is largely irrelevant as in any rational pull-based  
> mapping mechanism, the mapping information would be cached for all  
> but the initial packet.

That may be so, but it means that the behavior of the caching scheme  
will become important.

In any event, experimentation with the proposed schemes will  
hopefully result in a better understanding of what the effects are.

>> More specifically, with LISP-like proposals and TCP, potential  
>> issues are things like a 3-second timeout if the first (SYN)  
>> packet is dropped.
>
> I'll ask again:  how does this ARP thing work again?

First off, all the ARP implementations I know of queue the packet  
during the loopkup, i.e., no loss. Second, the duration of an ARP  
lookup vs. the end-to-end RTT is typically miniscule. This is not so  
with LISP-like schemes.

Lars

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