On Sat, Sep 25, 2010 at 5:12 PM, Kartik Vashishta <[email protected]> wrote:
> I have an /etc/hostname.nxge700001 file:
> Cat /etc/hostname.nxge700001
> Group vlan711 up
>
> What do these contents of /etc/hostname.nxge700001 mean? Please help.

I assume that what you meant to say was there is one line in the file:

group vlan711 up

Also, you didn't mention what release of Solaris or OpenSolaris you
are using.  I'll go with the assumption you are running Solaris 10 or
a variant of SXCE or OpenSolaris that is old enough to act like
Solaris 10.

The existence of the file causes VLAN 700 on nxge1 to be plumbed as
interface nxge700001.  Traffic that goes over nxge1 via the nxge700001
interace will have an 802.1q header added with a vid field of 700.
See http://en.wikipedia.org/wiki/IEEE_802.1Q if you need an overview
of VLAN tagging.  The use of a VLAN interface name of vlanid * 1000 +
"nic instance number" is commonly referred to as the PPA hack.

Anyway, just because the file exists the system does:

ifconfig nxge700001 plumb

After the interface is plumbed, each line of it is fed to ifconfig.
That is, the following is executed:

ifconfig nxge700001 group vlan711 up

There are two different things that happen there.  First, the IPMP
group name on the inerface is set to "vlan711".  Second, the interface
is marked as up.  Since it doesn't have an assigned address, whether
it is up or not doesn't matter much.

FWIW, when there is a single line in the file, "up" is not needed.
When the script that processes /etc/hostname.* files sees a file with
a single line, "ifconfig <interface> up" is executed after processing
the contents.

It is confusing that an IPMP group called vlan711 is configured on a
NIC that talks on VLAN 700.

-- 
Mike Gerdts
http://mgerdts.blogspot.com/
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