Re: [v6ops] new draft: draft-chen-v6ops-ipv6-roaming-analysis

Jouni,

2013/7/18, Jouni Korhonen <jouni.nospam@gmail.com>:
>
> Gang,
>
> I was more like thinking of IR.33, TAP documents and the IPv6 white paper,
> etc stuff that GSMA has worked on. I think aligning with GSMA is important
> since they are far more important for 3GPP roaming aspects than any IETF
> document.
>
> Then some other notes. When reading the draft I always get confused
> when the draft assumes local breakout, when home routed traffic and
> when a specific "phenomenon" is due visited/home APN/HLR intentional
> configuration, licensing restriction or some known implementation
> issue on some vendor equipment. Also some behaviour are due the UE
> specific implementation beyond what 3GPP specs say. I would encourage
> to detail these assumptions out on each claim/description so that
> possible readers can map the issues to their deployments easier
> without guesswork.

I noticed that after the discussions on the list. We will complete the
descriptions to detail the assumed conditions. Also the GSMA document
would be cited to align the consideration.

> In Section 3.1 it states:
>
>   "Subscriber Server).  When the subscriber roams to the IPv4 network,"
>
> Does this mean the visited SGSN would not implement PDP Type IPv6?

The reason is visited SGSN doesn't support PDP Type IPv4v6, other than
PDP type IPv6. PDP type IPv6 has well been supported AFAIK.

>I know such exist(ed) but how common are those on live today?

When we do IPv6 trials, we have to upgrade all SGSN to understand PDP
Type IPv4v6. I also had some discussions with other operator
colleague. They also have same issues.

>   "land to retrieve the subscriber profile.  Roaming with IPv4v6 type in
>    the subscriber profile may cause issues because the visited SGSN/SGW
>    can't parse the information.  The subscriber is failed to register in
>    this case."
>
> I guess you mean above SGSN/MME.. an SGW not implementing IPv4v6 would
> be kind of surprising. I have seen a MME that did not implement IPv4v6 very
> early of rel-8 testing phase, though.

If I correct, SGSNs introduce IPv4v6 since Release-8; SGWs introduces
IPv4v6 since Release-9. You may be right it's a rare case if SGW
doesn't implement IPv4v6. The failure cases we are facing are mainly
on SGSN.  SGW is listed just because the rel-8 SGW implementations.
Thank you for the information there is no such case in the real world.
We will update the draft with your comments accordingly.

> Here I would like to see text
> describing what is the actual failure scenario when the subscriber gets
> no connection at all. I know one SGSN+HLR combination which is very
> unlikely to happen in commercial networks.

The failure scenario is subscriber can't register to the visited
network. Would you mind to add something to help me understand what's
your expected texts here?

> In Section 3.2. it states:
>
>   "of single IP version in order to achieve equivalent results.  Some
>    operators may turn off the function only allow one PDP/PDN is alive
>    for each subscriber.  For example, IPv6 PDP/PDN would be rejected if
>    the subscriber has an active IPv4 PDP/PDN.  Therefore, the subscriber
>    may lost IPv6 connection in the visited network.  Even the two"
>
> I am confused here. Are we assuming visited GGSN here?

Yes. The local breakout is considered here.

>
> In Section 4.1. it states:
>
>   "requested protocol and always adhere to IPv4 when roaming.  Those
>    fallback mechanisms are deserved to be implemented and standardized
>    timely."
>
> Does the standardization mean fallback mechanisms beyond what 3GPP
> already defined?

A proper fallback mechanism is not defined in 3GPP.  The advocated
standardization more likes to do defacto standard. But the suggestion
is align with cuurent 3GPP spec. And some implementations are
available.

Best Regards

Gang

> - Jouni
>
> On Jul 15, 2013, at 6:28 PM, GangChen <phdgang@gmail.com> wrote:
>
>> 2013/7/15, Jouni Korhonen <jouni.nospam@gmail.com>:
>>>
>>> Gang,
>>>
>>> Regarding roaming in general, have you looked at what GSMA is doing
>>> on this front? I was kind of expecting at least a reference to some
>>> GSMA document since they are quite important when it comes to 3GPP
>>> based networks & roaming.
>>
>> I guess GSMA IR.21 could be cited here.
>> http://www.gsma.com/newsroom/wp-content/uploads/2012/06/IR2180.pdf
>> Most failures cases are occurred if a roaming partner's IR.21 only
>> states v4 support
>>
>> -g
>>
>>
>>>
>>> - Jouni
>>>
>>>
>>> On Jul 15, 2013, at 5:56 AM, GangChen <phdgang@gmail.com> wrote:
>>>
>>>> Hi Alexis,
>>>>
>>>> Thanks for the interests. We are experiencing the issues recently when
>>>> IPv6 is tested/deployed. For the goal of the draft, it reports that to
>>>> the community and hopes to mature IPv6 supports either by encouraging
>>>> proper implementations on mobile terminals or completing global
>>>> roaming contracts.
>>>>
>>>> Your reviews/comments are appreciated
>>>>
>>>> BRs
>>>>
>>>> Gang
>>>>
>>>> 2013/7/9, Alexis Munoz (Gmail) <amunoz0481@gmail.com>:
>>>>> It looks so interesting. I will check it and I will give you my
>>>>> comments
>>>>> very soon.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Alexis Muñoz
>>>>>
>>>>> -----Original Message-----
>>>>> From: v6ops-bounces@ietf.org [mailto:v6ops-bounces@ietf.org] On Behalf
>>>>> Of
>>>>> fred@cisco.com
>>>>> Sent: Tuesday, July 09, 2013 7:45 AM
>>>>> To: v6ops@ietf.org
>>>>> Cc: draft-chen-v6ops-ipv6-roaming-analysis@tools.ietf.org
>>>>> Subject: [v6ops] new draft: draft-chen-v6ops-ipv6-roaming-analysis
>>>>>
>>>>>
>>>>> A new draft has been posted, at
>>>>> http://tools.ietf.org/html/draft-chen-v6ops-ipv6-roaming-analysis.
>>>>> Please
>>>>> take a look at it and comment.
>>>>> _______________________________________________
>>>>> v6ops mailing list
>>>>> v6ops@ietf.org
>>>>> https://www.ietf.org/mailman/listinfo/v6ops
>>>>>
>>>>>
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>>>
>
>