Fragments

[martin]

Perlman, Addison-Wesley 2000
This is written by one of the authors of "Network Security". It's all about routers, bridges and their protocols. Each protocol is treated in painful detail. The author also gives her (well-founded) criticism of most protocols, including her own.

You know, the spanning tree algorithm (also affectionally known as 802.1D) was actually invented by Perlman, so she gives a pretty thorough exposition on it. With a little poem to go with it. She also invented a number of other protocols, such as IS-IS and the later DEC protocols.

The discussion about where names like "layer 2 switch", "layer 3 switch", or even plain "switch" comes from, is interesting. And comforting, since I never understood what they were really going on about. Perman confirms my suspicion that it's all marketing speak and actually means practically exactly the same as "bridge", resp. "router". Nothing more, nothing less. Recently, I've seen marketing stuff referring to "layer 4 switches", which is less clear to me what they represent. Since layer 4 equals the transport layer (TCP, UDP, SPX, for instance), that would make these switches circuit level proxies, wouldn't it? Like SOCKS, or something.

I quit reading the book with my full attention about 100 pages from the end, since the detailed discussion got beyond me. I probably missed some crucial information upstream somewhere and derailed. But I'm sure to return to this volume many times during my remaining career, and sooner or later, even those last almost indigestible chapters will succumb.