dhcpcd-discuss

On Sun, Feb 12, 2017 at 5:12 PM, Roy Marples <roy@xxxxxxxxxxxx> wrote:

> Hi Shahid
>
> On 10/02/17 15:37, Shahid Mahmood wrote:
> > Hello Roy,
> > Just a quick question on section 17.1.3 of RFC 3315. It states 3 options
> > available to the client in order to select and Advertise message:
> >
> > --- quote
> >
> >    Upon receipt of one or more valid Advertise messages, the client
> >    selects one or more Advertise messages based upon the following
> >    criteria.
> >
> >    -  Those Advertise messages with the highest server preference value
> >       are preferred over all other Advertise messages.
> >
> >    -  Within a group of Advertise messages with the same server
> >       preference value, a client MAY select those servers whose
> >       Advertise messages advertise information of interest to the
> >       client.  For example, the client may choose a server that returned
> >       an advertisement with configuration options of interest to the
> >       client.
> >
> >    -  The client MAY choose a less-preferred server if that server has a
> >       better set of advertised parameters, such as the available
> >       addresses advertised in IAs.
> >
> > --- end quote
> >
> > Specifically, when does client pick the last option:
> >
> >    -  The client MAY choose a less-preferred server if that server has a
> >       better set of advertised parameters, such as the available
> >       addresses advertised in IAs.
> >
> > Also, can application influence this choice (with parameter or
> something)?
>
> Currently there is no preference selection available.
> dhcpcd binds the first one received and keeps it. It does not change to
> another lease as such.
>

It is observed that dhcpc picks the first server if two happen to send
Advertize almost simultaneously.
The first advertize has Pref-Value 250, 2nd one 253. It does not seem to
follow 1st bullet in sec 17.1.3 in RFC 3315.


>
> Because dhcpcd can trivially remove the lease it applied, changing to a
> new lease from a new server wouldn't be too onerous. How would you say
> to prefer one over another?
>

At this point, I just wanted to confirm if the behavior is in accordance
with the RFC.


>
> Roy
>
> -shahid