Tech Note #37: Introduction to the TOAD
1998 Bionic Buffalo Corporation; All Rights Reserved.
12 June 1998
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A network address and protocol may be given for advertised objects, to allow would-be
clients to contact the object. Depending on the protocol, the network address may be that of
a broker or other agent, instead of the address of the object itself.
Additional properties may describe the objects in question. Unlike the properties of the
segment prefix, these additional properties are informational and do not necessarily restrict
the domain of the advertisement or search. They may be used to narrow choices when
several possible matches are available.
Protocol parameters may be used in control or status segments to describe frequency of
broadcast or other characteristics of a node’s operation.
Whenever broadcast operation is used, the hop limit is set very small to preclude transmission
outside of the local network and possibly one adjacent network. The use of the broadcast modes
is intended for small, local networks, so there should be no need for its use on the internet.
Routers should block such messages, for security reasons, since deliberate, malicious
introduction of these messages into a network from the outside could pose hazards to the target.
The management of networks of TOAD nodes is allowed by the protocol, but its discussion is
beyond the scope of this document.
The Use of Objects, Classes, and Properties
A main goal of TOAD design was to allow manufacturers to produce network-ready devices
and appliances, which could be plugged into a LAN, home, or office network with little or no
configuration by the user. To illustrate the possible applications, this section describes several
For many of these applications to work to their fullest extents, the firms producing these devices
or appliances must agree on the definition of object classes. This agreement will allow objects
on the network to inter-operate. Each of these examples includes a discussion of the interfaces
or classes, which should be defined.
Definition of common classes or interfaces may be done by any convenient means, and
presupposes a larger object architecture such as CORBA. The TOAD design was done to allow
easy interoperation with CORBA and CORBA Services, although other object architectures
might be used.
Specification of an object class or interface in CORBA requires creating the Interface Definition
Language (IDL) description of the objects. The behaviour of the objects’ methods must be
described using a separate mechanism.