[Asterisk-Users] Should ICMP port unreachable generate a BYE request?

[Dipole Moment]

Hi all,

I'm researching random call drops on our Asterisk and would like to
make sure whether it's something wrong with our VoIP provider or with
the Asterisk.  I sniffed traffic between Asterisk and our VoIP
provider's SIP gateway, and observed that in the middle of the
conversation an RTP stream originating from Asterisk gets an ICMP port
unreachable from provider's SIP gateway at random times and
conversation seems to go on for a while, but after a while a few more
port unreachables are observed and Asterisk sends BYE request to both
parties.

I wonder if it is it normal for Asterisk to send BYE requests to both
parties once it gets a port unreach even though noone from the either
end has hanged up the call?  If yes, then why doesn't it send BYE
request on the first unreach it sees?  Or is it some tunable parameter
that can be set via configuration files?  Or should I mail the sniffer
dump to my provider and ask them to fix their gateway?

Thanks!