Hi Tommy,

thanks for the info. I understand the need for using TCP and also the need for 
standardization here. It was just not clear to me what exactly need to be done 
because I didn’t have the reference to the draft.

You as you said below what you need is guidance on "how to encapsulate IKE and 
IPSec in a stream-like protocol“. Maybe that the wording we could also use in 
the charter to clarify what the wg will do…?

Mirja


> Am 31.08.2016 um 16:10 schrieb Tommy Pauly <[email protected]>:
> 
> Thanks everyone for chiming in. I want to highlight that the point of the 
> draft is to nail down the IKE-specific concerns of encapsulating the tunnel 
> in streams. As mentioned by Tero, this includes how to specify the boundaries 
> of messages within the stream; and how to interact with MOBIKE, redirection, 
> fragmentation, and so on.
> 
> The protocol really could be summarized as "how to encapsulate IKE and IPSec 
> in any stream-like protocol", and it specifically mentions that this applies 
> beyond direct TCP streams. If we want to have work in other groups to change 
> how the outer TCP works, that's great. Any work that would be done in that 
> area could benefit such tunnels without requiring changes to the IPSec aspect.
> 
> The practice of putting tunnels over TCP when absolutely necessitated by the 
> restrictions of a network is common practice. If we do not specify this here, 
> devices will still do it, just without a standard. As Yoav mentioned, this is 
> common practice across essentially every non-IKE VPN tunnel protocol, and 
> leads to a splintering of protocols to do the same thing. Please do read the 
> draft (current version 
> https://tools.ietf.org/html/draft-ietf-ipsecme-tcp-encaps-02); it 
> specifically calls out why TCP-in-TCP (which can happen in this scenario) is 
> problematic, and so it specifies several times that this is only to be used 
> as a fallback from UDP.
> 
> We've done fairly extensive testing around the implications of this protocol, 
> and made sure we were satisfied with the results before we proposed the 
> draft. 
> 
> Thanks,
> Tommy
> 
>> On Aug 31, 2016, at 6:17 AM, Yoav Nir <[email protected]> wrote:
>> 
>> 
>>> On 31 Aug 2016, at 3:21 PM, Tero Kivinen <[email protected]> wrote:
>>> 
>>> Mirja Kuehlewind (IETF) writes:
>>>> thanks for the reply. Very helpful background info. Maybe even put
>>>> more information in the charter text. 
>>> 
>>> I think it belongs to the actual draft, not to the charter, perhaps we
>>> should put the draft-ietf-ipsecme-tcp-encaps in the charter, as
>>> a working draft. 
>>> 
>>>> When you say "the 3gpp specification did not consider or specify all
>>>> needed things for the protocol“, can you be more specific here?
>>> 
>>> 3GPP just said that we make TCP tunnel, put 16-bit length header in
>>> front telling the length of the IKE or ESP packet coming after that,
>>> and then we put either ESP packet directly, or 4-bytes of zeros
>>> (Non-ESP marker we use in UDP encapsulation) and IKE packet.
>>> 
>>> There is also keepalive timer sending packets over TCP to keep it
>>> alive (again similar what we have in UDP).
>> 
>> One more bit of information: some vendors have had a non-standardized 
>> version of this or something similar for years. My employer has had it since 
>> 2003, except that the header is a bit different. The pretty ubiquitous SSL 
>> VPNs do pretty much the same except that they encrypt IP packets plus 
>> headers into TLS records rather than ESP packets before streaming them over 
>> TCP.
>> 
>> Perhaps “TCP tunnel” is a misleading term because the TCP does not tunnel. 
>> That is part of the function of ESP. Perhaps we should be saying “TCP 
>> streaming of ESP and IKE packets”
>> 
>> Yoav
>> _______________________________________________
>> IPsec mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/ipsec
> 

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