You *are* a god...

This really should go in the wiki.


-----Original Message-----
From: [EMAIL PROTECTED] on behalf of ottomeister
Sent: Wed 3/21/2007 9:20 PM
To: SunRay-Users mailing list
Subject: Re: [SunRay-Users] connecting to servers via dns and broadcast
 
On 3/21/07, Thomas L Baca <[EMAIL PROTECTED]> wrote:
> This brings forward the general question of what are the semantics of
> -a, -A, and -L.  From the docs, the simple rule is to use -a for
> "dedicated interconnect" and -A for "shared network".  The manual says
> that -A also turns on the "LAN connection" a la -L.

'-a <interface>' tells SRSS that the subnet attached to that interface
is an "interconnect", a subnet that is dedicated to carrying Sun Ray
traffic and that has no connectivity to any other subnets.  When you
set up an interconnect 'utadm' knows that the Sun Rays will need to
be told to contact the server at its IP address on the interconnect, so
that's how 'utadm' sets up the DHCP parameters for this subnet.  The
fact that this subnet is an interconnect is remembered; it's a factor
when this server tries to decide whether to offer sessions to Sun Ray
units, and it's important if this server ever needs to redirect DTUs on
the interconnect to other servers on the interconnect.

'-L on' tells SRSS that it's OK for this server to offer sessions to Sun
Ray units that connect from subnets that are not dedicated
interconnects.  By default SRSS will offer sessions only to units
that connect from subnets that have been declared (by 'utadm -a')
to be interconnects.

'-A <subnet>' tells SRSS that you want to set up DHCP on this
server to deliver parameters to the given subnet, and possibly to
issue IP address leases to the given subnet.  '-A' tells SRSS that
even though you want DHCP to do something for this subnet, the
subnet is not an interconnect -- it's just another subnet on a
fully-connected internet.  . '-A' therefore implies that you want this
server to offer sessions to Sun Ray units on non-interconnect
subnets, so in addition to setting up DHCP it automatically does
the equivalent of '-L on' for you.

> In our facility, we have multiple class C IP subnets running on the
> same VLAN (we have no direct control of VLAN configs - that's campus
> networking) and are starting to have DTUs and servers on various of
> the IP subnets (but on the same LAN!).  I believe this circumstance is
> causing some of our confusion as it may not be common in Sun Ray
> deployments.

If you have no interconnects then you won't use '-a' at all.  Your
Sun Rays are on your internet so you'd use '-A' for each subnet
where you wanted the Sun Ray server to offer some degree of
DHCP service to the subnet.  If you didn't want the server to
provide DHCP service to any subnets then you'd just run '-L on'
once.

> Also, this all ties in to the various status flags in the utgstatus
> output...  How do the T N U A M flags relate to those utadm configs?

-a/-A/-L do not affect T or N.

T and N are per-host flags.  T is "Trusted", which means that that
server has demonstrated that it belongs to the same Sun Ray host
group as the server you ran 'utgstatus' against.  'N' is "oNline" which
means that the server may bid to provide a new session when one
needs to be created within its group.  (That's controlled by 'utadm -n'
and 'utadm -f'.)

U, A and M are per-subnet flags.  U (for Up) means that this server
has recently received Sun Ray group membership announcements
from that server over that subnet.  A (for Active) means that that
server is willing to offer sessions to Sun Ray units that connect to it
over that subnet.  (So, for instance, a server that is offering sessions
only to interconnects will not advertise A on its non-interconnect
subnets, and other servers should not automatically redirect units
to that server's address on those non-A subnets.)  M means that
that server considers that subnet to be an interconnect.  (M is for
Managed.  We could have used I for interconnect but with some
fonts I looks like l or 1 so we went with M.  D for Dedicated was
another possibility but we worried that people might mistake it  for
Down.)

So '-a' causes M and causes A on M subnets.  '-A' and '-L on'
cause A on non-M subnets.

U isn't tied to any options, it's produced entirely by packet
reception.

OttoM.
__
ottomeister

Disclaimer: These are my opinions.  I do not speak for my employer.
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