Subject: Re: [tram] New Version Notification for draft-patil-tram-turn-serv-disc-01.txt

From: "Prashanth Patil (praspati)" <[email-masked]>
Date: Mon, 19 May 2014 18:11:40 +0000

Hi Karl,

On 5/18/14 6:13 PM, "Karl Stahl" <[email-masked]> wrote:

>I browsed through this document and to me it looks mature enough to be
>pushed forward (hopefully soon) to get an IANA anycast address etc., so
>these things can be put into current WebRTC browsers. As we know, many
>enterprises cannot use WebRTC at all today due to their restrictive
>firewall policies - they need a TURN server on their LAN, discovered
>and used by the WebRTC browsers to even begin using WebRTC.
>
>However, I raised a few questions and some suggestions
>http://www.ietf.org/mail-archive/web/tram/current/msg00480.html
>at the end of the previous version of this draft that never became
>discussed and remain:
>
>A) Under 8.2 there is a suggested way to assure that the TURN server
>returned by the anycast method, is provided by the network
>provider (and not some far away TURN server that should not be trusted
>to use without authentication): "... can set an IP TTL on their TURN
>requests that limits how far they can travel into the public Internet."
>
>I suggest that this TTL limitation is specified (e.g. Don't look further
>than 3 steps - local firewall + max 2 ISP routers) and brought into
>section "5. Discovery using Anycast" of the draft.

I think the decision should be left up to the application. We could,
maybe, make a recommendation at best (i.e. it is not a MUST).

>
>B) Shall we really have more than one method? If the Anycast method can
>be used by everyone, why then also have DHCP and now a two more methods?

There are essentially 2 methods described in the draft (1) Service
resolution and (2) Anycast. We'll probably need both if we want to
maximize chances of discovery.
DHCP happens to be one method to obtain the domain-name for (1) Service
resolution. While the DHCP method may not workable in some cases, the
other two methods (one of them inspired by draft-kist-alto-3pdisc) could
offer better results. We can do away with DHCP,  if that is the WG
consensus.

>
>I assume you intend that all webrtc browsers implement and can use all
>methods? Or? (If a service provider e.g. deploys DHCP discovered TURN
>servers, but some webrtc browser in some operating system don't
>find/cannot use the TURN server, it would be bad.)
>
>In previous discussions, there were some fears that DHCP options are
>not available in some common OSs. If so, I think the DHCP method should
>be skipped. 
>
>Also, if the other methods (other than anycast) may fail, why have them?

Anycast may fail, too.

> 
>Are they better to deploy and provision for network service providers?
>
>And will webrtc browsers implement all these methods?
>
>Do we have input/feedback on these questions?
>
>Should the "connect speed factor" not also be considered? Even though
>the auto discovery can be done in advance of a call, we should consider
>the mobility use case. With a mobile client changing network,
>LAN/LTE/public WiFi etc., we want to get up and run as soon as possible,
>so the auto discovery of a new TURN server should not be a tedious process
>
>And should the quick anycast auto discovery not be the first to be
>tried/used (which it is not now in the draft)?

Given that there is a service resolution mechanism for TURN over DTLS
(http://tools.ietf.org/html/draft-ietf-tram-stun-dtls-02#page-6), it seems
useful to do service resolution before.

>
>C) I noticed that referenced I-D.ietf-geopriv-res-gw-lis-discovery
>is now RFC7216.

Thanks, will update.

-Prashanth

>
>/Karl
>
>
>-----Ursprungligt meddelande-----
>Från: tram [mailto:[email-masked]] För Prashanth Patil (praspati)
>Skickat: den 2 maj 2014 12:02
>Till: [email-masked]
>Ämne: [tram] FW: New Version Notification for
>draft-patil-tram-turn-serv-disc-01.txt
>
>A new revision of the TURN server discovery draft has been published.
>Notable updates :
>
>* 300 (Try Alternate) response for anycast.
>* Mechanism described in draft-kist-alto-3pdisc i.e. using the clients own
>address to populate the DNS reverse zone (i.e., in-addr.arpa or ip6.arpa)
>with appropriate NAPTR records pointing to the TURN server.
>* Learning domain names from own identity.
>
>-Prashanth
>
>
>On 5/2/14 3:25 PM, "[email-masked]" <[email-masked]>
>wrote:
>
>>
>>A new version of I-D, draft-patil-tram-turn-serv-disc-01.txt
>>has been successfully submitted by Prashanth Patil and posted to the
>>IETF repository.
>>
>>Name:		draft-patil-tram-turn-serv-disc
>>Revision:	01
>>Title:		TURN Server Auto Discovery
>>Document date:	2014-05-02
>>Group:		Individual Submission
>>Pages:		11
>>URL:            
>>http://www.ietf.org/internet-drafts/draft-patil-tram-turn-serv-disc-01.tx
>>t
>>Status:         
>>https://datatracker.ietf.org/doc/draft-patil-tram-turn-serv-disc/
>>Htmlized:       
>>http://tools.ietf.org/html/draft-patil-tram-turn-serv-disc-01
>>Diff:           
>>http://www.ietf.org/rfcdiff?url2=draft-patil-tram-turn-serv-disc-01
>>
>>Abstract:
>>   Current Traversal Using Relays around NAT (TURN) server discovery
>>   mechanisms are relatively static and limited to explicit
>>   configuration.  These are usually under the administrative control of
>>   the application or TURN service provider, and not the enterprise or
>>   the ISP, the network in which the client is located.  Enterprises and
>>   ISPs wishing to provide their own TURN servers need auto discovery
>>   mechanisms that a TURN client could use with no or minimal
>>   configuration.  This document describes two such mechanisms for TURN
>>   server discovery.
>>
>>                 
>>        
>>
>>
>>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.
>>
>>The IETF Secretariat
>>
>
>_______________________________________________
>tram mailing list
>[email-masked]
>https://www.ietf.org/mailman/listinfo/tram
>

---

From: "Karl Stahl" <[email-masked]>
Date: Tue, 20 May 2014 00:27:55 +0200

I read "We'll probably need both if we want to maximize chances of
discovery." in the draft also, but don't really get it.

Do you mean that if the network provider offers one particular TURN server
to his network users, that TURN server should be advertised in both
suggested ways?

/Karl

-----Ursprungligt meddelande-----
Från: tram [mailto:[email-masked]] För Prashanth Patil (praspati)
Skickat: den 19 maj 2014 20:12
Till: Karl Stahl; [email-masked]; 'Simon Perreault'
Ämne: Re: [tram] New Version Notification for

Hi Karl,

On 5/18/14 6:13 PM, "Karl Stahl" <[email-masked]> wrote:

>returned by the anycast method, is provided by the network provider 
>(and not some far away TURN server that should not be trusted to use 
>without authentication): "... can set an IP TTL on their TURN requests 
>that limits how far they can travel into the public Internet."
>
>I suggest that this TTL limitation is specified (e.g. Don't look 
>further than 3 steps - local firewall + max 2 ISP routers) and brought 
>into section "5. Discovery using Anycast" of the draft.

I think the decision should be left up to the application. We could, maybe,
make a recommendation at best (i.e. it is not a MUST).

There are essentially 2 methods described in the draft (1) Service
resolution and (2) Anycast. We'll probably need both if we want to maximize
chances of discovery.
DHCP happens to be one method to obtain the domain-name for (1) Service
resolution. While the DHCP method may not workable in some cases, the other
two methods (one of them inspired by draft-kist-alto-3pdisc) could offer
better results. We can do away with DHCP,  if that is the WG consensus.

Anycast may fail, too.

>LAN/LTE/public WiFi etc., we want to get up and run as soon as 
>possible, so the auto discovery of a new TURN server should not be a 
>tedious process
>

Thanks, will update.

-Prashanth

>* Mechanism described in draft-kist-alto-3pdisc i.e. using the clients 
>own address to populate the DNS reverse zone (i.e., in-addr.arpa or 
>ip6.arpa) with appropriate NAPTR records pointing to the TURN server.

---

From: "Tirumaleswar Reddy (tireddy)" <[email-masked]>
Date: Tue, 20 May 2014 07:14:27 +0000

> -----Original Message-----
> From: tram [mailto:[email-masked]] On Behalf Of Karl Stahl
> Sent: Tuesday, May 20, 2014 3:58 AM
> To: Prashanth Patil (praspati); [email-masked]; 'Simon Perreault'
> Subject: Re: [tram] New Version Notification for draft-patil-tram-turn-serv-disc-
> 01.txt
> 

With Secure DHCPv6 with Public Key http://tools.ietf.org/html/draft-ietf-dhc-sedhcpv6-02, DHCP has benefits over Anycast.
But since DHCP is not workable in some cases, clients may end-up using both the techniques (for e.g. use happy-eyeball mechanism) and give precedence to TURN server learnt using secure DHCP.

> to his network users, that TURN server should be advertised in both

Yes

-Tiru

---

From: "Prashanth Patil (praspati)" <[email-masked]>
Date: Tue, 20 May 2014 09:40:21 +0000

>to his network users, that TURN server should be advertised in both

By maximize, the draft really means discovering servers that may not
support all discoverable methods. For example, if a provider already has
TURN application service provisioned in DNS (as in RFC5928), it can be
readily discovered without needing anycast.

-Prashanth
 
>maybe,
>other

---

From: "Karl Stahl" <[email-masked]>
Date: Tue, 20 May 2014 11:59:29 +0200

I think the draft should elaborate some around these (and Tiru's) thoughts
of having multiple methods.

/Karl

-----Ursprungligt meddelande-----
Från: tram [mailto:[email-masked]] För Prashanth Patil (praspati)
Skickat: den 20 maj 2014 11:40
Till: [email-masked]
Ämne: Re: [tram] New Version Notification for

On 5/20/14 3:57 AM, "Karl Stahl" <[email-masked]> wrote:

>Do you mean that if the network provider offers one particular TURN 
>server to his network users, that TURN server should be advertised in 
>both suggested ways?

By maximize, the draft really means discovering servers that may not support
all discoverable methods. For example, if a provider already has TURN
application service provisioned in DNS (as in RFC5928), it can be readily
discovered without needing anycast.

-Prashanth
 
>>pushed forward (hopefully soon) to get an IANA anycast address etc., 
>>so these things can be put into current WebRTC browsers. As we know, 
>>many enterprises cannot use WebRTC at all today due to their 
>>restrictive firewall policies - they need a TURN server on their LAN, 
>>discovered and used by the WebRTC browsers to even begin using WebRTC.
>>
>>B) Shall we really have more than one method? If the Anycast method 
>>can be used by everyone, why then also have DHCP and now a two more
methods?
>other two methods (one of them inspired by draft-kist-alto-3pdisc) 
>could offer better results. We can do away with DHCP,  if that is the 
>WG consensus.
>
>
>>
>>not available in some common OSs. If so, I think the DHCP method 
>>should be skipped.
>>
>>the auto discovery can be done in advance of a call, we should 
>>consider the mobility use case. With a mobile client changing network, 
>(http://tools.ietf.org/html/draft-ietf-tram-stun-dtls-02#page-6), it 
>seems useful to do service resolution before.
>
>>
>>>http://www.ietf.org/internet-drafts/draft-patil-tram-turn-serv-disc-0
>>>1
>>>.tx
>>>t
>>>Status:

---

From: "Karl Stahl" <[email-masked]>
Date: Tue, 20 May 2014 14:35:43 +0200

In this multiple methods discussion, what about this WebRTC use case that I
think will be common:

An enterprise installs a TURN server with one LAN-port (paralleling its
firewall), because it wants to use WebRTC but maintain a restrictive
firewall policy, that stops WebRTC media or it wants to have a better media
path than through his ordinary data crowded Internet access.

Would it then be sufficient to add a route in its ordinary firewall, so the
anycast-address goes to that local TURN-server - and the Web-browsers really
use that path?

I don't see the enterprise wanting to set up other discovery methods also.

/Karl

-----Ursprungligt meddelande-----
Från: Tirumaleswar Reddy (tireddy) [mailto:[email-masked]] 
Skickat: den 20 maj 2014 09:14
Till: Karl Stahl; Prashanth Patil (praspati); [email-masked]; 'Simon
Perreault'
Ämne: RE: [tram] New Version Notification for
draft-patil-tram-turn-serv-disc-01.txt

> Subject: Re: [tram] New Version Notification for 
> draft-patil-tram-turn-serv-disc- 01.txt
> 

With Secure DHCPv6 with Public Key
http://tools.ietf.org/html/draft-ietf-dhc-sedhcpv6-02, DHCP has benefits
over Anycast.
But since DHCP is not workable in some cases, clients may end-up using both
the techniques (for e.g. use happy-eyeball mechanism) and give precedence to
TURN server learnt using secure DHCP.

Yes

-Tiru

-Prashanth

> >I browsed through this document and to me it looks mature enough to 
> >be pushed forward (hopefully soon) to get an IANA anycast address 
> >etc., so these things can be put into current WebRTC browsers. As we 
> >know, many enterprises cannot use WebRTC at all today due to their 
> >without authentication): "... can set an IP TTL on their TURN 
> >further than 3 steps - local firewall + max 2 ISP routers) and 
> >brought into section "5. Discovery using Anycast" of the draft.
> 
methods?
> DHCP happens to be one method to obtain the domain-name for (1) 
> Service resolution. While the DHCP method may not workable in some 
> cases, the other two methods (one of them inspired by 
> draft-kist-alto-3pdisc) could offer better results. We can do away with
DHCP,  if that is the WG consensus.
> 
> 
> >
> >I assume you intend that all webrtc browsers implement and can use 
> >all methods? Or? (If a service provider e.g. deploys DHCP discovered 
> >TURN servers, but some webrtc browser in some operating system don't 
> >consider the mobility use case. With a mobile client changing 
> >network, LAN/LTE/public WiFi etc., we want to get up and run as soon 
> >as possible, so the auto discovery of a new TURN server should not be 
> >a tedious process
> >
> >* Mechanism described in draft-kist-alto-3pdisc i.e. using the 
> >clients own address to populate the DNS reverse zone (i.e., 
> >in-addr.arpa or
> >>http://www.ietf.org/internet-drafts/draft-patil-tram-turn-serv-disc-
> >>01
> >>.tx
> >>t
> >>Status: