Re: [tram] Multiple allocations SV: I-D Action: draft-ietf-tram-turnbis-15.txt

["Martin Gartner" <[e-mail]>]

In my thinking, a TURN server is just a remote extension of the available 
interfaces which a client can use to try network connections by using ICE.
All client interfaces are used when trying to find the best network path 
with ICE, so it seems just logical to do the same for the TURN server, to 
use all of its interfaces when trying to find the best network path. And to 
make this possible, there must be a way to inform the client about more than 
one available relay address, if the network provided TURN server has access 
to more than one network path.
So it seems what Karl proposes is definitely needed.
Martin

-----Ursprungligt meddelande----- 
From: Karl Stahl
Sent: Tuesday, March 20, 2018 8:55 PM
To: 'Konda, Tirumaleswar Reddy' ; [e-mail]
Subject: Multiple allocations SV: [tram] I-D Action: 
draft-ietf-tram-turnbis-15.txt

> This revision addresses comments from Mark, Karl and Noriyuki Torii.
My comment about need for multiple allocations is NOT addressed.

Let me explain more clearly why multiple allocations is needed:

ICE is about finding all/many paths for the media, e.g. with the help of
TURN servers.
Those paths are not over ONE IPv4 network, over ONE IPv6 network or EXACTLY
ONE OF EACH.
If fact, it is more common that you have several IPv4 networks paths.

Now that we have network provided TURN servers, you only ask for Allocation
once (contrary to application provided TURN servers, where you can be
directed to Allocate several times.) and thus we need all relay addresses in
one allocation request.

Wasn't that the reason dual allocation was requested? The need for multiple
allocation is stronger!

Please address this, e.g. like below (seems you are almost there).

/Karl


******************* Previous *******************

Allowing a turn allocation to return multiple relayed transport addresses,
beyond ONE IPv4 and ONE IPv6 (which may sit on the same or on different
interfaces/network segments), seems like very small step now when the dual
allocation was put in place in this draft. We certainly need it (some
reasons below) if TURN is going to be used where needed and we cannot wait
for any additional draft.

Seems like it is sufficient to extent this table (found in draft 14) with 3
new values (as shown):

16.  STUN Attributes

   This STUN extension defines the following attributes:

     0x000C: CHANNEL-NUMBER
     0x000D: LIFETIME
     0x0010: Reserved (was BANDWIDTH)
     0x0012: XOR-PEER-ADDRESS
     0x0013: DATA
     0x0016: XOR-RELAYED-ADDRESS
     0x0017: REQUESTED-ADDRESS-FAMILY
     0x0018: EVEN-PORT
     0x0019: REQUESTED-TRANSPORT
     0x001A: DONT-FRAGMENT
     0x0021: Reserved (was TIMER-VAL)
     0x0022: RESERVATION-TOKEN
     TBD-CA: ADDITIONAL-ADDRESS-FAMILY
ADDITIONAL-ADDRESS-ALL
ADDITIONAL-ADDRESS-ALLV4
ADDITIONAL-ADDRESS-ALLV6
     TBD-CA: ADDRESS-ERROR-CODE
     TBD-CA: ICMP

Actually, browsing through the draft for ADDITIONAL-ADDRESS-FAMILY, very
little text seems to be added for generalization to  ADDITIONAL-ADDRESS-xxx.
Almost everything applies to ADDITIONAL-ADDRESS-xxx and can be reused.

ADDITIONAL-ADDRESS-ALL should be the default for any modern TURN client.

Check! - We need this now.

Thanks,
Karl

> -----Original Message-----
> From: Karl Stahl [mailto:[e-mail]]
> Sent: Sunday, March 4, 2018 10:36 PM
> To: 'Marc Petit-Huguenin' <[e-mail]>; Konda, Tirumaleswar Reddy
> <[e-mail]>; [e-mail]
> Subject: SV: [tram] Review of dual allocation in TURNbis-11
>
> Hi,
>
> When we now have "dual allocation" into this draft (I see on page 26: "If
the
> client wishes to obtain one IPv6 and one IPv4 relayed transport address
then
> it includes an ADDITIONAL-ADDRESS-FAMILY transport address then it") can
> we not generalize that further and allow MORE THAN ONE relayed transport
> address (of any family) in response to an allocation?
>
> I mean that a TURN server could have several relay interfaces at different
IP-
> addresses into different networks - not just the Internet, but also a VoIP
> (higher quality) network e.g. by some triple play service provider, an IMS
> network or some branch office network.
>
> I think this is specifically important for network provided/auto
discovered
> turn servers (application provided turn servers could instead just list
several
> turn servers).
>
> I saw someone snipped this about "SINGLE relayed transport address per
> allocation request"
> > > https://tools.ietf.org/html/rfc6156#section-3
> > > <snip>
> > >
> > >    TURN servers allocate a single relayed transport address per
> > >    allocation request.  Therefore, Allocate requests cannot carry more
> > >    than one REQUESTED-ADDRESS-FAMILY attribute.  Consequently, a
> client
> > >    that wishes to allocate more than one relayed transport address at
a
> > >    TURN server (e.g., an IPv4 and an IPv6 address) needs to perform
> > >    several allocation requests (one allocation request per relayed
> > >    transport address).
> > > </snip>
>
> but if that is remedied now, it seems like a small step to generalize so
we can
> get multiple relayed transport addresses from one allocate request?
>
> /Karl


-----Ursprungligt meddelande-----
Från: tram [mailto:[e-mail]] För Konda, Tirumaleswar Reddy
Skickat: den 18 mars 2018 09:51
Till: [e-mail]
Ämne: Re: [tram] I-D Action: draft-ietf-tram-turnbis-15.txt

This revision addresses comments from Mark, Karl and Noriyuki Torii.

-Tiru

> -----Original Message-----
> From: tram [mailto:[e-mail]] On Behalf Of internet-
> [e-mail]
> Sent: Sunday, March 18, 2018 8:43 AM
> To: [e-mail]
> Cc: [e-mail]
> Subject: [tram] I-D Action: draft-ietf-tram-turnbis-15.txt
>
>
> 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 WG of the
> IETF.
>
>         Title           : Traversal Using Relays around NAT (TURN): Relay
Extensions
> to Session Traversal Utilities for NAT (STUN)
>         Authors         : Tirumaleswar Reddy
>                           Alan Johnston
>                           Philip Matthews
>                           Jonathan Rosenberg
> Filename        : draft-ietf-tram-turnbis-15.txt
> Pages           : 84
> Date            : 2018-03-18
>
> Abstract:
>    If a host is located behind a NAT, then in certain situations it can
>    be impossible for that host to communicate directly with other hosts
>    (peers).  In these situations, it is necessary for the host to use
>    the services of an intermediate node that acts as a communication
>    relay.  This specification defines a protocol, called TURN (Traversal
>    Using Relays around NAT), that allows the host to control the
>    operation of the relay and to exchange packets with its peers using
>    the relay.  TURN differs from some other relay control protocols in
>    that it allows a client to communicate with multiple peers using a
>    single relay address.
>
>    The TURN protocol was designed to be used as part of the ICE
>    (Interactive Connectivity Establishment) approach to NAT traversal,
>    though it also can be used without ICE.
>
>    This document obsoletes RFC 5766 and RFC 6156.
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-tram-turnbis/
>
> There are also htmlized versions available at:
> https://tools.ietf.org/html/draft-ietf-tram-turnbis-15
> https://datatracker.ietf.org/doc/html/draft-ietf-tram-turnbis-15
>
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-tram-turnbis-15
>
>
> 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/
>
> _______________________________________________
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