Subject: [tram] I-D Action: draft-ietf-tram-turn-mobility-01.txt

From: [email-masked]
Date: Thu, 10 Mar 2016 20:39:03 -0800

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the TURN Revised and Modernized of the IETF.

        Title           : Mobility with TURN
        Authors         : Dan Wing
                          Prashanth Patil
                          Tirumaleswar Reddy
                          Paal-Erik Martinsen
	Filename        : draft-ietf-tram-turn-mobility-01.txt
	Pages           : 12
	Date            : 2016-03-10

Abstract:
   It is desirable to minimize traffic disruption caused by changing IP
   address during a mobility event.  One mechanism to minimize
   disruption is to expose a shorter network path to the mobility event
   so only the local network elements are aware of the changed IP
   address but the remote peer is unaware of the changed IP address.

   This draft provides such an IP address mobility solution using
   Traversal Using Relays around NAT (TURN).  This is achieved by
   allowing a client to retain an allocation on the TURN server when the
   IP address of the client changes.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-tram-turn-mobility/

There's also a htmlized version available at:
https://tools.ietf.org/html/draft-ietf-tram-turn-mobility-01

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-tram-turn-mobility-01

Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

---

From: "Tirumaleswar Reddy (tireddy)" <[email-masked]>
Date: Fri, 11 Mar 2016 04:48:42 +0000

This revision adds support for make-before-break and addresses comments from Brandon.

-Tiru

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---

From: Brandon Williams <[email-masked]>
Date: Mon, 21 Mar 2016 14:08:11 -0400

Hi Tiru,

Thanks for the update. I've got two minor comments.

The new text about fragmentation and ticket length is less specific than 
the old text, but it still repeats guidance from the RFC that I believe 
we've agreed to change in STUNbis. How about instead of this: "... 
assume that the path MTU is unknown and MUST ensure that the ticket 
length is restricted to avoid UDP fragmentation ...", we say this: "... 
assume that the path MTU is unknown and use a ticket length in 
accordance with published guidance on STUN UDP fragmentation ...". This 
wording defers all requirements language to the STUN RFC but still calls 
out the possible concern.

In the paragraph describing the handling of a verified Refresh request, 
it states "The server then updates it's state data with the new client 
IP address and port but does not discard the old 5-tuple from it's state 
data." However, in the next paragraph, the new text states "After 
receiving any of those messages, a TURN server updates its 5-tuple with 
the new client IP address and port." I think what you want in the second 
paragraph is "After receiving any of those messages, a TURN server 
discards the 5-tuple associated with the old MOBILITY-TICKET from its 
state data." In that paragraph, you can probably also say that it 
discards the old MOBILITY-TICKET at that point without waiting for the 
timeout, although the text about holding onto the old MOBILITY-TICKET 
hasn't appeared yet (it's in the next paragraph).

--Brandon

-- 
Brandon Williams; Chief Architect
Cloud Networking; Akamai Technologies Inc.

---

From: "Tirumaleswar Reddy (tireddy)" <[email-masked]>
Date: Tue, 22 Mar 2016 07:53:41 +0000

Hi Brandon,

Please see inline 

> From: tram [mailto:[email-masked]] On Behalf Of Brandon Williams
> Sent: Monday, March 21, 2016 11:38 PM
> To: [email-masked]
> Subject: Re: [tram] I-D Action: draft-ietf-tram-turn-mobility-01.txt
> 
> Hi Tiru,
> 
> The new text about fragmentation and ticket length is less specific than the
> old text, but it still repeats guidance from the RFC that I believe we've agreed
> to change in STUNbis. 

I don't see any specific changes in STUNbis yet to handle fragmentation !

> How about instead of this: "...
> assume that the path MTU is unknown and use a ticket length in accordance
> with published guidance on STUN UDP fragmentation ...". This wording
> defers all requirements language to the STUN RFC but still calls out the
> possible concern.

Okay, updated.

> 
> In the paragraph describing the handling of a verified Refresh request, it
> states "The server then updates it's state data with the new client IP address
> and port but does not discard the old 5-tuple from it's state data." However,
> in the next paragraph, the new text states "After receiving any of those
> messages, a TURN server updates its 5-tuple with the new client IP address
> and port." I think what you want in the second paragraph is "After receiving
> any of those messages, a TURN server discards the 5-tuple associated with
> the old MOBILITY-TICKET from its state data." In that paragraph, you can
> probably also say that it discards the old MOBILITY-TICKET at that point
> without waiting for the timeout, although the text about holding onto the old
> MOBILITY-TICKET hasn't appeared yet (it's in the next paragraph).

NEW:
After receiving any of those messages, a TURN server discards the 5-tuple associated with the old MOBILITY-TICKET and the old MOBILITY-TICKET from its state data.

-Tiru

> >> Please note that it may take a couple of minutes from the time of
> >> submission until the htmlized version and diff are available at
> tools.ietf.org.
> >>