[e2e] local recovery or not local recovery, was: Re: Satellite networks latency and data corruption

[Detlef Bosau]

alok wrote:
> 
>> For 3G networks, my position is that the gateways between Internet and 
>> mobile network are typically quite large computer systems, each one 
>> serving some few hundreds of flows. In this case, the effort is 
>> acceptable.
>>
>> In satellite networks: I don´t know. Particularly the state variables 
>> for ARQ in high bandwidth systems may turn out inacceptable high.
>>
>> 2.: Fairness:
>>
>> If ARQ is placed on the end system, the whole network path "enjoys" 
>> necessary retransmissions. Particularly, when a packet must be sent 
>> 100 times or more to be successfuly received ad least once, it may 
>> increase the network performance to plate ARQ on intermediate sywtems.
>>
> if it is wire line/fibre, i think we do not have to worry about losses.
> 
>> Once again on 3G networks: Typically, 3G networks are only used as 
>> access line. So the major part of the path typically resides in the 
>> wirebound internet. Therefore, it makes sense not to bother ther 
>> internet with retransmissions. Even more, ARQ in 3G networks is done 
>> on radio block level, which is more efficient than ARQ on pakcet level.
>>
> well I did see your website, but ....what is "3G"?

Third Generation mobile networks.

http://www.3gpp.org/

I think "Third Generation Wide Area Mobile Networking and Ubiquitous 
Computing" sounds better - therefore sells better than: UMTS :-) *SCNR*

> it does not use anything but the same fiber and copper or media than was 
> already there, right?
> 

Yes, I think the wireless media was already there ;-) (There must be 
some papers by James C. Maxwell about this.... and certainly, JC will 
add: another british invention/discovery, however: JCM was a scot :-))



>> This is mainly covered by 2. Fairness.
>>
>> Of couse, the utilization of a link decreases if it is fed up with 
>> retransmissions only.
>>
>> I think, the consideration can turn out quite different, depending on 
>> the actual scenario: E.g. a satellite mobile phone could be attached 
>> to the Internnet. Or a satellite link could be used for Internet 
>> backbone connections, perhaps wheather dependent in combination with a 
>> fibre link.
>>
> By fairness, do you mean that "i use up someone else's 
> space/time/bandwidth"? no that is not what I was asking. What on the 
> internet is "fairness"?

In this particular case I meant: I do not use more bandwidth for 
retransmission than others do.

Basically, fairness on the Internet means that competing flows use a 
fair share of common ressources.



-- 
Detlef Bosau
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