Does anyone know if there is an updated version of this book? Year 2000
seems so distant now...
http://www.amazon.com/dp/B0051TM4RC/ref=rdr_kindle_ext_tmb
--Andrey
I too have been wondering if this would ever get revived..... the
only book on NX-OS software is so basic too 
David.
All vendors should be writing in depth architecture books. The Juniper MX book is a great example. Tell us exactly what your product can do and we'll likely use more of it
You might want to take a look at the CEF book, which expands on this
http://www.amazon.com/Cisco-Express-Forwarding-ebook/dp/B0015V9DQU/
both of these are still very accurate on how IOS operates today. The
only major changes with IOS-XE is that IOS is now a process and packet
forwarding is handled in hardware instead of software.
For NX-OS and IOS-XR the software/operating system is wildly different
and I think there is a definite gap in literature out there.
You might want to take a look at the CEF book, which expands on this
http://www.amazon.com/Cisco-Express-Forwarding-ebook/dp/B0015V9DQU/both of these are still very accurate on how IOS operates today. The
only major changes with IOS-XE is that IOS is now a process and packet
forwarding is handled in hardware instead of software.
On the IOS-XE it's no longer single process, when you're running in the
modular version. It's getting complicated.
For NX-OS and IOS-XR the software/operating system is wildly different
and I think there is a definite gap in literature out there.
For now, there's Cisco Live and techtorials about architecture and
inner works. There will be a book, or two 
I asked an IOS expert of my acquaintance, and she said -
On the flip side, if you document what your product is probably incapable of
due to the design architecture, the salescritters won't be able to sell as many
of them...
I think the biggest problem in that regard is the gap between what the
switch or router architecture is capable of and what the current release of
IOS actually supports.
This is generally what appears on the "roadmap" but, historically, not all
of it gets delivered in a timely manner, and some features aren't delivered
at all before the hardware is superseded.
Aled
A couple of thoughts:
1. The IOS specific parts of both Inside Cisco IOS Software Architecture
are still pretty relevant. The RIB is now a separate process, and there
are other changes, but the software architecture (of IOS specifically!)
is pretty close to what's there.
2. The hardware architecture isn't current, but, IMHO, those sections
are still "useful," for understanding the general way routers are laid
out in terms of driver to ASIC interaction, packet receive processing,
and things like that.
3. I've been talking to folks in Cisco to encourage them to write a new
version. I'm busy on another project (The Art of Network Architecture),
and have a couple of other ideas backed up in my mind to work on, and
don't have access to the code or hardware architecture folks any longer,
so it would be difficult for me. I would be glad to help anyone in cisco
who wants to pull such a book together in any way I can, but I'm just
not in a position to actually write an updated version of this pair of
books.
HTH
Russ