Subject: [pcp] Issue 16 discussion: PCP lifetime expiration with active traffic

From: "Dan Wing" <[email-masked]>
Date: Tue, 8 Feb 2011 10:30:25 -0800

http://trac.tools.ietf.org/wg/pcp/trac/ticket/16

Description:
    A PCP-allocated port has a lifetime associated with it. When
    that lifetime expires, do we want to simply delete the
    mapping or do we want active inside->outside traffic (using
    that mapping) to keep the connection alive?

    The difference requires the NAT (and/or PCP server) to
    remember which mappings have been created with PCP (which
    should be deleted strictly on their expiration time) versus
    which mappings have been created by dynamic outbound
    connections (e.g., TCP SYN) (which should have their
    mapping lifetimes extended when active inside->outside
    traffic is seen).

I would like to close this issue.  Note this issue applies 
only to MAP4 and MAP6 OpCodes (which create an incoming mapping), 
because we have already decided that the PEER4 and PEER6 
OpCodes (which query and [possibly] adjust the lifetime of
an implicit dynamic mapping (e.g., TCP SYN)) will not modify 
the NAT's existing behavior.

Please discuss the merits of:

  * immediately terminating the mapping when the PCP-controlled
    lifetime expires, even if there is active traffic.  As 
    stated above, this requires the NAT remember this mapping 
    was created by a MAP OpCode.  It might remember this by 
    using a certain port range, or a bit in its mapping table,
    or whatever else the implementation wants to do.
OR
  * keep the mapping alive as long as there is inside->outside
    traffic.

-d

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From: Reinaldo Penno <[email-masked]>
Date: Tue, 8 Feb 2011 16:07:04 -0500

>   * keep the mapping alive as long as there is inside->outside

The former is more consistent with the lifetime definition but I think in
actual deployments customers will prefer the latter.

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From: Francis Dupont <[email-masked]>
Date: Wed, 09 Feb 2011 13:51:15 +0100

In your previous mail you wrote:

   Description:

   

=> there are two sides for possible answers:
 - from the NAT point of view it is mainly a matter of
  implementation. With an EIM/EIF NAT no difference (second option)
  is easier, with other NATs it is the opposite.

 - from the client point of view the real question is whether the
  client expects an explicit dynamic mapping to survive its
  expiry or worst its explicit deletion. IMHO the answer is no,
  this is why I am in favor of the first option with at least
  a SHOULD.

Regards

[email-masked]