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Cell Relay Retreat>ION Archive>month:1996-Jun> msg00086



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Maybe RSVP and Q.2931, but not NHRP

  • From: Telford001@aol.com
  • Date: Fri, 7 Jun 1996 00:58:44 -0400
  • cc: Sam.Wilson@ed.ac.uk, smarcus@bbnplanet.com, ion@nexen.com, Telford001@aol.com

In a message dated 96-06-06 23:33:37 EDT, mohta@necom830.hpcl.titech.ac.jp
(Masataka Ohta) writes:

>> >> In the TTI VLAN router, switching from one VLAN to another
>> >> is equivalent to loading a register with a new value.

>> This operation takes place transparently as the packet switch
>> control sofware executes. In IP terminology

>My original statement is that:

>	>> Making something logical only add unnecessary management burden with
>	>> no real benefit.

>if the operation is transparent to IP and unfamiliar to IP administrator,
>it's burden is worse.

I am not sure what you mean.  It seems to be an argument
against subnet masks, which have been immensely useful
albeit something of a kludge.

>But, wait.

>> A subnetwork simply
>> does not necessarily correspond to a single physical
>> interface.

>Hmm, you only mean you can configure physically contiguous interfaces
>into a single subnet, don't you? If so, it is not as bad as "logical"
>and there is no reason to call it "logical", except that there is
>hype that something logical "were" good.

Usual English terminology for hiding the hardware details is either
logical or virtual.  Unix and Multics provide logical IO.  X allows
a high resolution raster graphics device to serve as multiple
virtual high resolution raster graphics devices.

In the case of the TTI VLAN router, the device is logically
equivalent to multiple LAN switches which are interconnected
by a router (functionality) operating at bus bandwidth.
The ports which are grouped to form a single logical
LAN (or WAN) switch need not actually be physically
contiguous.

I tend to prefer to the term "logical" to "virtual" because
in Spanish "virtual" often has the connotations of
"real" in English.  Unfortunately, my term "Logical
SubBridge" did not catch on and every else uses
VLAN.

Joachim Martillo
Inventor of the VLAN
President 
Telford Tools, Inc.
"Garage Mechanics for the I-Way"
17 Pleasant Hill Ave.
Dorchester/Mattapan, MA 02126-2813
V:  617-298-1617
F:  617-298-1745
E:  Telford001@aol.com