On 11/8/07, Nicolas Williams <[EMAIL PROTECTED]> wrote:
> On Wed, Nov 07, 2007 at 11:50:09PM -0500, Peter Memishian wrote:
> > > I've put together some of my initial thoughts on the design for link
> > > layer discovery at http://www.opensolaris.org/os/project/lld/design
> >
> > I took a quick look at this last night and I think this is heading in a
> > good direction. Some initial thoughts:
> >
> > * It's worth exploring how best to align the subcommands with the way
> > other
> > subcommands work in dladm. For instance, existing subcommands are
> > verb-noun where "noun" is either the type of the link or the class of
> > the link. Accordingly, it might be more fitting to have a flag to
> > show-link that gives the discovered info for that link. Similarly,
> > maybe something like `discover-link' would be a better fit for
> > performing discovery? [...]
>
> How about 'scan-link'? That would match what scan-wifi does. Is it
> possible to discover VLANs?
Yes potentially -- the advertisement of the VLAN data is optional. If
I am reading the spec correctly, it allows for (source == device
generating the LLDP packet):
- Advertising if the source supports vlans
- Advertising if the source has enabled vlan
- Identification of the vlan used for untagged or priority tagged
frames from the source
- Identification of tagged vlans configured on the source port (I
think -- I think this is what sec F.3 is talking about in the spec)
>
> Incidentally, I note that the dladm show-link -p and show-wifi -p output
> formats differ radically. Why? (Change the Subject if responding to
> this -- it's a different thread :)
>
> > * The show-peer -v option output is an interesting solution to the
>
> show-peer makes sense for point-to-point links, but an Ethernet NIC is
> connected to a dumb bridge wouldn't qualify, no? See also the above
> question about VLAN discovery.
True. It uses an ethernet multicast address to send the packets, so
in a non-switched environment, you could potentially see frames from
multiple systems. LLDP seems to allow this, I'm not sure how the
other protocols (CDP, EDP) handle this (if at all).
>
> > 80-column output problem. If we went with that approach, it should be
> > available uniformly across the show-* subcommands and we should figure
> > out how it interacts with parseable-output mode. Also, in general
> > we've avoided multi-word field names because they complicate parsing
> > of the output and require quoting with -o <field>.
>
> dladm show-wifi -p output includes
>
> BSSID/IBSSID=<ssid>
>
> That '/' makes it difficult to use dladm show-wifi -p output in a
> script!
>
> Also, is the ESSID properly quoted? Is it safe to eval dladm show-wifi
> -p output in a shell?
>
> Nico
> --
>
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