| My understanding is that the routing software for the DECswitch 900s
lets you route between VLANs (i.e. backplane configurable LANs).
Today, the only way to set up VLANs is with PORTswitches and Repeaters -
putting them onto different backplane LANs and then routing between
them. Before this announcement, you could only switch between them in
the hub, or you could use an external router. Many people did not
consider the switched LANs to be VLANs, since the broadcast domains
were not routed.
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| There are several things being talked about in this string; let me
clarify. Firstly, "Routeabout software" among other things is a
synonym for the much-anticipated routing upgrade for the 2 DECswitch
products. Response .1 refers to what I believe is an unannounced
product in the making; all I'll say here is that it is a new
wide-area brouter line. Finally, "Class 1 VLANs" is essentially
LAN-hopping on the DEChub 900 backplane with some new GUI; what the
announcement is trying to say is that you can software-configure ports on
a DECswitch into LANs on the backplane. Of course such VLANs are restricted
to a single DEChub 900 and comprise a single repeated 10 Mbps domain
in the case of Ethernet and "concentrated" 100 Mbps in the case of FDDI.
So it wouldn't make sense, for example, to connect two or more
bridge ports into the same VLAN. That would however make sense
with Class 2 VLANs, where VLANs are not restricted to the hub
backplane.
With Class 2 you could configure extended LANs across separate switches
not necessarily in the same hub (or indeed not even in a hub). These
VLANs would allow significantly higher bandwidth since they don't
comprise ports in the same collision domain. It's a much more powerful
concept since you can essentially configure and change separate
*switched* (not repeated) LANs with a mouse-click.. ie with a graphical
management tool instead of rewiring. The upcoming version of routing
upgrade will not support Class 2.
Anil
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