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Re: [RRG] Why delaying initial packets matters
Jari Arkko wrote:
In any case, I am completely in the dark with regards to how serious
this problem is in real life. And frankly, this thread is not giving me
much new information in that regard. It could be that its not a problem
at all. Or it is. I would suggest that we take this issue seriously and
make sure there is someone making a measurement of what the actual
impacts would be. Data needed! We don't necessarily have to have a
complete new routing system to test or simulate this; it would be
sufficient to introduce the drop/delay-the-first-packet effect.
While the impact to TCP-based things is likely to be
noticable-but-modest (TCP has to handle loss,
including first-packet loss), I think UDP protocols may need more scrutiny.
The short list of things that I think need further testing or analysis
or experience, regarding loss
or delay to the first packet:
ntp (think about it!)
snmp
snmptrap
l2tp
all the various *lm things (licence managers) - how many IT help desks
to we want to anger at once, really?
These are all in use, big time, and likely to be important to any site.
All are UDP. All need to work,
reliably, predictably, consistently. (Especially ntp.)
The other thing we should do is to go back to the tradeoff discussion
that David started; I found that useful. The questions that I have are:
1) Wouldn't a hybrid scheme be able to reduce the incidence of this
problem? 2) David's tradeoffs assumed that we operate either in push or
pull model. However, has it been established that we actually need a
separation architecture that needs these mappings? What about research
ideas such as compact routing?
I think it would be good to re-examine alternatives to push/pull mapping
schemes. They exist,
and like everything, have trade-offs.
How do those compare to push/pull for map-encaps and the trade-offs there?
Brian Dickson
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