Re: CARD protocol constants related / was: Re: CARD Review from Henrik Petander

hi Marco,

>>1. We need to rate-limit requests from the MN.
>>2. specify retransmission behavior for the MN.
>>3. specify retransmission behavior for the Current AR.
>>4. specify sending behavior for unsolicited CARD replies
>>
>>for (1), we need a protocol constant to say that the MN is not allowed 
>>to send
>>more than a certain number of requests per second. if it sends more 
>>than that,
>>the current AR just drops the requests. There shouldnt be an upper 
>>limit on
>>the number of requests.
> 
> 
> 
> In the recent draft, we have the following constants specified for that 
> purpose:
> CARD_RETRANSMISSION_INTERVAL = 1 second
> CARD_MAX_RETRIES = 3
> 
> As far as I remember, this is the mechanism and values you proposed,
> including the upper limit. This mechanism replaced the previous mechanism,
> which was based on the more dynamic approach using the rate-limiting flag.
> Do you now propose to drop the MAX_RETRIES limitation?

yes. the CARD_MAX_RETRIES is not needed.

also replace CARD_RETRANSMISSION_INTERNAL to CARD_REQUEST_RATE.

replace

    To counteract this problem, the MN MUST send
    only one CARD Request per CARD_RETRANSMISSION_INTERVAL and not more
    than CARD_MAX_RETRIES. If the MN sends requests more frequently, the
    AR SHOULD drop the CARD requests and not process them.

    To counteract this problem, the MN MUST NOT send more than
    CARD_REQUEST_RATE requests per second. If the MN sends requests more
    frequently, the AR SHOULD drop the CARD requests and not process
    them.

in section 7

    CARD_REQUEST_RATE       2

I think 2 requests per second is okay.


>>for (2), we need protocol constants. one to say when to retransmit and 
>>one to
>>say when to give up.
> 
> 
> The current draft specifies the following:
> MN_AR_CARD_TIMEOUT = 1 sec
> MN_AR_CARD_RETRIES = 5
> 
> 
>>for (3), same as (2).
> 
> 
> The current draft specifies the following:
> AR_AR_CARD_TIMEOUT = 1 sec
> AR_AR_CARD_RETRIES = 3
> 
> Referring to Henrik's feedback and addressed issue, the proposal was to
> keep the MN-AR characteristics and to adjust the AR-AR characteristics 
> as follows:
> AR_AR_CARD_TIMEOUT: 300 ms
> AR_AR_CARD_RETRIES: 2
> 
> There was no feedback yet.
> Any comments?

this is fine with me.


>>(2) and (3) could share the same protocol constants.
> 
> 
> If we modify the AR-AR characteristics to counteract the issue
> Henrik referred to, this cannot be done.

okay.

Vijay