Indeed, 3COM has a product called "full-duplex repeater" (what a name...).
This is actually a hybrid of a switch and a repeater: it uses buffering of
incoming
frames and a round-robin method of forwarding them to all egress ports.
However, my question concerns the common device -- no buffering.
How can the port controller on cisco claim it is in full-duplex while it is
in half? Is it possible that 3COM "emulates" full-duplex during
autonegotiation,
and, if yes, what for?
==========================
""Howard C. Berkowitz"" <[EMAIL PROTECTED]> escribió en el mensaje
news:p0500190eb6d52a4dc981@[63.216.127.100]...
> >Hi ALL,
> >a fast Ether port on a cisco switch (2900XL)
> >connected to a hub (3com repeater) 10/100 port
> >reports auto-negotiated full-duplex, and works fine.
> >How can a normal hub (no buffering!) accept full-duplex?
> >To my undestanding this is impossible...
> >Am I wrong?
>
>
> The real problem here is that "hub" is a marketing, not a technical,
> term. In most technical discussions, what we mean by an Ethernet hub
> is a multiport repeater. If the 3Com device were defined as a
> multiport repeater, what you say would be completely true.
>
> Unfortunately, different vendors use "hub" in different ways. Cisco,
> actually, has been cleaner than most. When Cisco puts a capability
> into a "hub" that flatly is beyond the functionality of a multiport
> repeater, they tend to identify that as a distinct function, and
> often put that on a separate module. A good example of that is speed
> switching.
>
> Cabletron, as an example, tends to define "hub" as a shelf into which
> repeater, bridge/LAN switch, and router modules can plug. I can't say
> they strictly are wrong to do so, because there is no standard
> definition of hub. Their definition is more a logical one that it is
> a hubbing point for wiring, rather than phrased in terms of what
> happens to the bits on the wire.
>
> Interestingly, until Cabletron and Cisco got into a rather nasty and
> public licensing fight several years ago, Cabletron was quite
> possibly Cisco's largest customer for card-level IGS routers used in
> their hubs, and carrying a Cabletron part number. Not sure if
> Cabletron (or its successor companies) now makes its own router
> cards, or, if not, from whome they OEM them.
>
> My impression is that 3Com uses the term hub in a way fairly
> consistent with Cabletron.
> --
> "What Problem are you trying to solve?"
> ***send Cisco questions to the list, so all can benefit -- not
> directly to me***
>
> Howard C. Berkowitz [EMAIL PROTECTED]
> Technical Director, CertificationZone.com
> Senior Mgr. IP Protocols & Algorithms, Advanced Technology Investments,
> NortelNetworks (for ID only) but Cisco stockholder!
> "retired" Certified Cisco Systems Instructor (CID) #93005
>
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