[Csci551-talk] Re: questions on the shaikh paper

[John Heidemann]

On Thu, 05 Feb 2004 14:00:31 PST, Mehdi Sharifzadeh wrote: 
>
>>  I have the following questions on the Shaikh paper titled " Routing stability in congested networks"
>>
>> 1) What is the significance of the LOT ? Why has it been calculated for all the cases that they have experimented on? Why is it so imp?
>
>It is used to assign the cost to the transition from the last state to the
>init state. This is because it takes LOT time for the receiver timer to
>expire and find that the message has been lost. That's when the state of
>the whole system should be initiated to the init state.

Exactly.  It's just there to represent the remaining time until
hold-time expires.

>> 2) How did they arrive on the values of parameters A1 and A2 in D2U cycle of BGP. Also what is a1 and a2 in the equations given?
>>
>
>Shaikh's master thesis [20] has a nice explanation of these parameters
>and Ra and Rb states
>(http://www.research.att.com/~ashaikh/papers/ms-thesis00.pdf).
>The initial 3*RTT is the value for RTO which is
>doubled in the case of each retransmission.

And ultimately these values derive from TCP timeout handling.
That's the subject of this week's class :-)

   -John Heidemann