Subject: [Ietf-behave] Growing mapping refresh timers

From: David Barrett <[email-masked]>
Date: Mon, 11 Jul 2005 19:03:29 -0700 (PDT)

Having just read-through the latest UDP draft, I noticed I've been 
seeing behavior in the real world that doesn't fit the range of 
possibilities outlined.  Specifically, I've seen the mapping timer grow 
up to a certain point through use, rather than use a fixed timeout.

For example, I created a simple mapping-timeout test that sent a 
"delayed ping" -- a ping that doesn't reply until after a certain delay. 
 On a certain NAT I found I could initially do a delayed-ping up to 16 
seconds, and it'd work fine on the first time.  And if I bumped up by 
powers of two, I could get to a delayed-ping time of 256 seconds, 
without trouble.  But if I started out with a delayed-ping of 256 (or 
indeed, anything over 16), it would fail and I'd hear no response.

My theory is that it's growing the mapping timer in line with activity. 
 I haven't done an exhaustive analysis (ie, does it grow incrementally, 
or does it upgrade in one step from 16 to 256 seconds?) but either way, 
I didn't see this type of behavior mentioned.  (Though I guess it could 
fall under the broad category of "non-deterministic".)

Have you experienced this or heard of it elsewhere?

-david

---

From: "Francois Audet" <[email-masked]>
Date: Mon, 11 Jul 2005 19:19:41 -0700 (PDT)

Sounds like another form of unpredictability to me...

I'm not even surprised anymore by the bizarre behaviors out there...

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> [mailto:ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> David Barrett
> Sent: Monday, July 11, 2005 19:03
> To: 'Behave'
> Subject: [Ietf-behave] Growing mapping refresh timers
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