Re: [DMM] I-D Action: draft-ietf-dmm-ondemand-mobility-17.txt

[Tom Herbert <[e-mail]>]

On Tue, Mar 5, 2019 at 2:29 AM Moses, Danny <[e-mail]> wrote:
>
> Can you please provide a calling sequence of your proposal?
>

Something like:

s = socket(AF_INET6, SOCK_STREAM, 0) ;
setsockopt(s, IPPROTO_IP, PREFERRED_ADDRESS_TYPE,
IPV6_REQUIRE_SESSION_LASTING_IP)
if (connect(s, &serverInfo, sizeof(serverInfo)) < 0) {
   if (errno == EADDRNOTAVAIL) {
            // Didn't get address for requested type
  }
  ...
}

// To get address local address that was selected...
getsockname(s, &myaddr, &myaddrlen);


> Thanks,
> Danny
>
> -----Original Message-----
> From: Tom Herbert [mailto:[e-mail]]
> Sent: Monday, March 04, 2019 17:17
> To: Moses, Danny <[e-mail]>
> Cc: dmm <[e-mail]>
> Subject: Re: [DMM] I-D Action: draft-ietf-dmm-ondemand-mobility-17.txt
>
> On Mon, Mar 4, 2019 at 4:25 AM Moses, Danny <[e-mail]> wrote:
> >
> > Hi Tom,
> >
> > Fair question.
> >
> > I believe I mentioned that in one of my responses. The original definition was to use setsockopt() with new flags. However, some people raised the concern that this new feature changes the behavior of the function in a way that may confuse programmers and requested to use a new function (setsc()).
> >
> > The issue was due to the time it takes the function to process the request. In current Socket implementation, setsockopt() is a function that returns immediately to the caller. On the other hand, this new feature may trigger an exchange of packets between the IP stack in the mobile node and the network allocating the IP prefix. This exchange takes time and the function can return only after the exchange is completed. They insisted that we maintain the current 'immediate' return behavior of setsockopt() and introduce a new function that might 'block' the calling thread until it completes.
> >
> Hi Danny,
>
> It is unclear to me why address selection has to be done outside of binding the socket. It seems like the required functionality of the draft could be achieved by calling setsockopt to express desired address type and then calling connect on the socket. Connect will bind an address with the requested type and can obviously block if work needs to be done to find an appropriate address. This simplifies the API and addresses an ambiguity in the draft-- when setsc returns it is unclear if the address was somehow reserved for the socket use (e.g.
> this becomes pertinent if we were to add an interface to bind a unique address to a socket).
>
> Tom
>
> > Regards,
> > Danny
> >
> >
> >
> >
> > -----Original Message-----
> > From: dmm [mailto:[e-mail]] On Behalf Of Tom Herbert
> > Sent: Friday, February 22, 2019 22:08
> > To: dmm <[e-mail]>
> > Subject: Re: [DMM] I-D Action: draft-ietf-dmm-ondemand-mobility-17.txt
> >
> > Out of curiosity, why is the new API being portrayed as a system call
> > (setsc) instead of a socket option (the bar for adding a socket option is much lower ).
> >
> > Tom
> >
> > On Fri, Feb 22, 2019 at 6:19 AM <[e-mail]> wrote:
> > >
> > >
> > > A New Internet-Draft is available from the on-line Internet-Drafts directories.
> > > This draft is a work item of the Distributed Mobility Management WG of the IETF.
> > >
> > >         Title           : On Demand Mobility Management
> > >         Authors         : Alper Yegin
> > >                           Danny Moses
> > >                           Seil Jeon
> > >         Filename        : draft-ietf-dmm-ondemand-mobility-17.txt
> > >         Pages           : 18
> > >         Date            : 2019-02-22
> > >
> > > Abstract:
> > >    Applications differ with respect to whether they need session
> > >    continuity and/or IP address reachability.  The network providing the
> > >    same type of service to any mobile host and any application running
> > >    on the host yields inefficiencies, as described in [RFC7333].  This
> > >    document defines a new concep of enabling applications to influence
> > >    the network's mobility services (session continuity and/or IP address
> > >    reachability) on a per-Socket basis, and suggests extensions to the
> > >    networking stack's API to accomodate this concept.
> > >
> > >
> > > The IETF datatracker status page for this draft is:
> > > https://datatracker.ietf.org/doc/draft-ietf-dmm-ondemand-mobility/
> > >
> > > There are also htmlized versions available at:
> > > https://tools.ietf.org/html/draft-ietf-dmm-ondemand-mobility-17
> > > https://datatracker.ietf.org/doc/html/draft-ietf-dmm-ondemand-mobili
> > > ty
> > > -17
> > >
> > > A diff from the previous version is available at:
> > > https://www.ietf.org/rfcdiff?url2=draft-ietf-dmm-ondemand-mobility-1
> > > 7
> > >
> > >
> > > 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/
> > >
> > > _______________________________________________
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> >
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