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

[Noriyuki Torii <[e-mail]>]

Hi,

>From my understandings, current TURNbis specification is intended, as its
scope of, just a single IP addressed server nevertheless its IPv4/v6
co-allocation capability. Such a capablity is introduced for v4 <-> v6
communication, and not as a generalization for a multiple IP addressed
server.

IMHO, if a server with multiple IP addresses of the same family will be
deployed into service, idential form of allocation request currently
defined also should be sent to such a server. And the server must process
the request appropriately according to its network configuration.

In general, clients don't know, and shouldn't need to know, how many IP
addresses are given to the server communicating with, or how is the
topology of the network into where the server is deployed, etc.
So the client side request form selection is not usually possible.

Because of above, I'm afraid to say but I couldn't agree with the Karl's
proposal of the modification of request form with additional attributes,
although I can understand there exists the demand of specification for
multiple IP addressed server.

I think the generalization of TURN for multiple IP addressed server is
something need more discussion and separate publication.

Regards,
Noriyuki Torii

2018-03-21 4:55 GMT+09:00 Karl Stahl <[e-mail]>:
>> 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/
>>
>> _______________________________________________
>> tram mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/tram
>
> _______________________________________________
> tram mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/tram
>
> _______________________________________________
> tram mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/tram