Re: [v6ops] draft-ietf-v6ops-mobile-device-profile last call

[Alexandru Petrescu <[e-mail]>]

Le 23/02/2015 14:25, Dave Michaud a écrit :
> To further clarify the comment below, this is not a recommendation but
> it is the expected behaviour as per the 3GPP spec.
>
> Upon receiving a request for a dual-stack PDP, the network operator can
> return one of the following cause codes (there are a lot more options
> but these are the relevant ones for discussion):

And what is the Cause code number for "PDP Type IPv4IPv6 allowed"?

If there is no such Cause code then it would make sense to add it.

Alex

>
> Cause code 50: PDP Type IPv4 only allowed
> Cause code 51: PDP Type IPv6 only allowed
> Cause code 52: Single address bearers only allowed
>
> In the first 2 causes (CC50 & CC51), the UE is to accept the PDP type
> selected by the network (IPv4 or IPv6) and not proceed further. Cause
> code 52 is the mean by which the network signals that it will allow two
> distincts PDP of different address type. In that case only is the UE
> suppose to go back and request a second PDP with the alternate type not
> offered by the network at the same time cause code 52 was returned.
>
> "If the requested IPv4v6 PDP-Context is not supported by
>
> the network, *but IPv4 and IPv6 PDP types are allowed**…*” —> This is
> signalled with cause code 52.
>
>
>
> *
> *
> *Dave Michaud*
> Sr. Architect Mobility – Access Networks & IP Network Services
> Network Technology | Rogers Communications
> [e-mail] <mailto:[e-mail]> | tel:
> +1 647.747.9442 | mobile: [phone]
>
>
> From: "[e-mail]
> <mailto:[e-mail]>" <[e-mail]
> <mailto:[e-mail]>>
> Date: Monday, February 23, 2015 at 07:10
> To: Lorenzo Colitti <[e-mail] <mailto:[e-mail]>>
> Cc: IPv6 WG <[e-mail] <mailto:[e-mail]>>
> Subject: Re: [v6ops] draft-ietf-v6ops-mobile-device-profile last call
>
> Re-,
>
> Please see inline.
>
> Cheers,
>
> Med
>
> *De :*Lorenzo Colitti [mailto:[e-mail]]
> *Envoyé :* lundi 23 février 2015 11:49
> *À :* BOUCADAIR Mohamed IMT/OLN
> *Cc :* Mikael Abrahamsson; V6 Ops List
> *Objet :* Re: [v6ops] draft-ietf-v6ops-mobile-device-profile last call
>
> On Mon, Feb 23, 2015 at 5:39 PM, <[e-mail]
> <mailto:[e-mail]>> wrote:
>
> Operators who have deployed IPv6 report that running dual-stack over two
> PDP contexts is a very bad idea because it consumes 2x the network
> resources. Please don't recommend this unless you have evidence that
> this works well in production (not in testing).
>
> [Med] We are not recommending establishing systematically two PDP
> contexts. Please check the full recommendation provided below for your
> convenience.
>
>     C_REC#2:  The cellular host must comply with the behavior defined in
>
>               [TS.23060] [TS.23401] [TS.24008] for requesting a PDP-
>
>               Context type.  In particular, the cellular host must
>
>               request by default an IPv6 PDP-Context if the cellular host
>
>               is IPv6-only and request an IPv4v6 PDP-Context if the
>
>               cellular host is dual-stack or when the cellular host is
>
>               not aware of connectivity types requested by devices
>
>               connected to it (e.g., cellular host with LAN capabilities
>
>               as discussed in Section 3):
>
>               *  If the requested IPv4v6 PDP-Context is not supported by
>
>                  the network, but IPv4 and IPv6 PDP types are allowed,
>
>                  then the cellular host will be configured with an IPv4
>
>                  address or an IPv6 prefix by the network.  It must
>
>                  initiate another PDP-Context activation in addition to
>
>                  the one already activated for a given APN (Access Point
>
>                  Name).  The purpose of initiating a second PDP-Context
>
>                  is to achieve dual- stack connectivity by means of two
>
>                  PDP-Contexts.
>
> How are you "not recommending" this behaviour, if the text says that the
> device "must initiate another PDP-Context activation"?
>
> [Med] It seems you skipped “systematically” in my answer ;-). So, I
> confirm “we are not recommending establishing systematically two PDP
> contexts”. The default behavior is to ask for a IPv4v6 PDP-Context, but
> (1) if the IPv4v6 PDP-Context is not supported, and (2) if IPv4 and IPv6
> PDP types are allowed, two PDP contexts can be requested. The network is
> free to accept those or not. As you can see there are “if”s in this
> behavior. So to be accurate, this text does not recommend requesting two
> separate PDP contexts as default behavior, but it does not forbid it
> either.
>
>                   *  If the subscription data or network configuration
>     allows
>
>                      only one IP address family (IPv4 or IPv6), the cellular
>
>                      host must not request a second PDP-Context to the same
>
>                      APN for the other IP address family.
>
>                   The text above focuses on the specification part which
>
>                   explains the behavior for requesting IPv6-related PDP-
>
>                   Context(s).  Understanding this behavior is important to
>
>                   avoid having broken IPv6 implementations in cellular
>
>     devices.
>
> I find this last paragraph meaningless. What is it intended to convey?
>
> [Med] FWIW, the last paragraph was added as per a comment received from
> the mailing list:
> https://www.ietf.org/mail-archive/web/v6ops/current/msg14716.html. The
> point is that the set of cited specifications contains more details
> about how PDP contexts are to be handled compared to what is described
> in here (that is IPv6-sepcific).
>
>
>
>
>
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