On Wednesday, 12/03/2003 at 07:20 CST, Adam Thornton
<[EMAIL PROTECTED]> wrote:
> On Wed, 2003-12-03 at 18:54, Romney White wrote:
> > Mark:
> >
> > VSWITCH has an *optional* associated OSA Express device. If you don't
> > have one, you don't have external connectivity, but a VSWITCH is just
> > really a QDIO Guest LAN with an optional associated real QDIO device.
>
> Fair enough, but isn't the point of the VSWITCH to bridge your Linux
> guests into an external LAN, rather than VM (or Linux) having to act as
> a router?  In which case, a VSWITCH without external connectivity is,
> well, a guest LAN, innit?

Almost.  VSWITCHes are different from Guest LANs in the following ways:
- They are always PERSISTENT
- They are always owned by SYSTEM
- They cannot be defined by class G users
- They support IEEE VLAN id assignments
- They can be optionally "bridged" to an external network

When you combine the VLAN and bridging capabilities, you can use a
singleVSWITCH (one OSA connection) to bring data onboard for multiple VLAN
segments!   Way Cool!!

But you're right that, from a guest's point of view, a VSWITCH and Guest
LAN (OSA flavor) are identical.

Alan Altmark
Sr. Software Engineer
IBM z/VM Development

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