[ns] [DSR] Minimum "off" time for a node to generate a RERR

[Salvo Danilo Giuffrida]

I'm trying to setup a simulation of an ad-hoc wireless network using
DSR, where when a node's energy reaches a level <= to a certain
threshold, it is temporarely put in "off" mode, such that neighbor
nodes that send packets through it generate an RERR, and new routes
are built and used, that don't traverse the "dying" node. After a
while, anyway, the switched-off node should come back to the "on"
state, because it still has some energy to use (the threshold would be
tipically 20% of the initial energy at time 0), and also because it
might be the only intermediate node connecting two or more partitions
of the network.
Think of it like a form of survival instinct...
I'm having an hard time finding what is the minimum amount of time
that the node should be in the "off" state, and not receive/forward
any transmission (therefore not send positive ACKs), to be sure that
neighbors which are sending packets to it will report the link A->B to
be broken. I read the official RFC for DSR
(http://tools.ietf.org/html/rfc4728), and I've tried to compare it to
the implementation in NS-2, but I've not yet understood what time
interval represents the failure of a link.
>From what I've understood, in the 802.11 implementation of NS2,
RTSThresh=0 (look at 'ns-default.tcl'), which means that all packets
are sent using the RTS/CTS mechanism (doesn't this put too much
overhead?), therefore the value of "LongRetryLimit_", which is 4 (in
'ns-default.tcl'), is always used to determine the maximum number of
allowed retransmissions of a packet, before that link is considered
failed. So, I guess that minimum time=4*(SIFS+transmission time of a
frame), but how much is the transmission time of a frame?
Thanks a lot