Howard,
Is this from your upcoming book for ISPs? Can you provide a
name/title and when we can expect to see it on shelves.
TIA
Nigel .
----- Original Message -----
From: "Howard C. Berkowitz"
To:
Sent: Thursday, September 27, 2001 12:16 AM
Subject: RE: which layer BGP,RIP ,OSPF work on [7:21226]
> >My intention of creating this thread again was just to clarify things as
> >some of us concluded that BGP,RIP,OSPF are at network layer.
> >Why I quoted the stuff in capital and if it hurt some of the members ,I
am
> >sorry but it was just to highlight that this is given in Cisco Press book
> >and whose author is CCIE and ofcourse reviewed by Imran Qureshi Program
> >Manager from Cisco on CCIE series of books.
> >
> >So again is it right that
> >
> >1)RIP,BGP are at application
> >2)OSPF is at Transport layer
> >
>
> If Jeff said this, it is wrong. Simple as that.
>
> Even if the logic were that anything that runs over layer (N) must be
> layer (N+1), that would put RIP and BGP at Session, and ISIS at
> Network.
>
> The original OSI model defined in ISO 7498 was published in 1984 and
> did not contain routing protocols at all, nor did it contain
> connectionless communications.
>
> But if you really want a model:
>
>
> The Seven Deadly Layers
>
> By Howard C. Berkowitz
>
> Among the most frequent questions I'm asked in OSI teaching
> is, "Do I need to know what all the layers do?" This is especially
> true of management
> audiences, who "need to know" the power centers. (They may not know what a
> layer is, but they know there are seven of them and they don't want a
> single one to go unsupervised.)
>
> Over the years, I have found a useful analogy. Educational
> theory suggests we should start with something that the student knows
> and build from there. Therefore, I ask management audiences to
> reflect not on theoretical network architecture, but on sin.
> Specifically, I ask them to consider the Seven
> Deadly Sins (Note 0).
>
> These sins have definite relevance to the OSI Reference Model. The "most
> popular" deadly sins are analogies for the layers most important for
> non-developers to know about. Audiences think of sins in a fairly
consistent
> way.
>
> Approximately 75 percent immediately think of Lust. Lust, clearly,
> relates directlyto the Physical Layer. It is essential to be aware of
> the function of the Lust Layer, for that defines how to "plug in."
> (Note 1)
>
> Most of the remaining audience split between Avarice and Gluttony. These
> also are important in OSI. Avarice, or Greed, is often realized
> as the Bottom Line in business. One is closer to understanding the
> Tao of OSI when one realizes that it places the Bottom Line (i.e.
> what OSI does for real user applications programs) on Top. The top of
> the Avarice Layer is the Service Access Point to the Application, or
> Avarice, Layer. ([Note 2)
>
> Those members of the audience who thought first of Gluttony also have some
> understanding of OSI. Gluttony deals with establishing a relationship
> between a mouth entity and a food entity. Network deals with the next
> course while Transport deals with the end goal of dessert. Users
> really need to know the functions of Application, Transport/Network
> (as the distinction blurs here), and Physical. They often also need
> to know the characteristics of the data link layer.
> Since Data Link has to deal with collisions, master/slave
> relationships, etc., it may correspond to the sin of Anger. I tend
> to associate the sin of Pride with the Presentation Layer, on the
> grounds that Presentation is rather prideful to think that it
> justifies its own layer.
>
> There is always one in the audience, however, who thinks of Sloth. Sloth
is a
> difficult sin. How does one confess it? "Bless me, I have slothed?"
> "Forgive me for committing sloth?" How can I commit not doing
> something? Since Sloth is a sin we really have trouble talking
> about,and involves not doing useful things, it is a relevant analogy
> to the Session Layer.
>
> Both Sloth and Session are needed for theological completeness, but
> their relevance to the ordinary sinner or the OSI user is fairly
> limited. [Note 4]
>
> If we were to redesign the OSI Reference Model today, its exact number
> of layers would be controversial, but it would almost certaily not be
> seven. The flight from sevenness is seen in Internet usage and in
> the more obscure (but useful) ISO Technical Report 10000 taxonomy for
> defining
> protocol stacks (i.e., International Standardized Protocols). Internet
> practice does use layered protocol stacks, but these rarely have seven
> layers (Network File System is an exception). Typically, an application
> service such as File Transfer Protocol (FTP) includes the functions of
> the top three OSI layers, and in turn layers on top of TCP, a Transport
> layer protocol. TCP, in turn, layers on top of IP, a network layer
> protocol. IP runs over a generic Interface or Hardware layer that
> include Data Link and Physical layers.
>
> In like manner, OSI stack specifications have a top A- or B-specification
> that defines a particular set of Application, Presentation, and Session
> protocols and their options. The A- or B-profile runs over a lower layer
> stack definition, the first letters of which identify the transport and
> network protocols in use, followed by numbers referring to the data
> link and physical layers. While little known outside OSI circles,
> this ISO 10000 methodology is useful as a notation for many multilayerd
> protocol stacks. (Note
> 3) Research funding is being sought to evaluate the possible
> relevance of the Seven
> Dwarves to OSI.
>
> (Note 0) Just as there are many theological interpretations in
> religion, this is not the only interpretation of "sevenness" and OSI
> layering. David Piscitello independently presented a different mapping
> of sins to layers in the early 1980s. A Mark Russell presentation gave
> the author insight on the meaning of confessing sloth.
>
> (Note 1) When presenting these analogies at an IEEE conference in New
> York, a woman's clear voice rang out from the back of the room.
> "Well, I'm glad SOME
> standards body is defining how to plug in things correctly. God
> knows most male engineers don't understand that at all."
>
> (Note 2) This part of the analogy can continue into Application
> ServiceElements: ACSE (the Avarice Control Service Element), ROSE (the
Remote
> Organization Submission Element), etc.
>
> (Note 3) After their first reading of Presentation Context Negotiation and
> ASN.1 Basic Encoding Rules, some nominate the sin of Pride as the proper
> analogy for the Presentation Layer.
>
> (Note 4) Session actually does useful things. The widely used Remote
> Procedure Call (RPC) protocol, which underlies NFS, is a pure session
> layer protocol. NetBIOS, as distinct from NetBEUI, also essentially
> is a session layer protocol.
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