This is the best book I've read on IGP Routing Protocols and their implementation on Cisco Routers. The book takes a reader from basic IP routing fundamentals through to in-depth implementation of the most complex IGP routing protocols. The book is easy to read and flows in very logical manner. I especially enjoyed the chapter (8) on Cisco's EIGRP; It was the most detailed coverage I have read on Cisco's proprietary Interior routing protocol.

Additional Comments:

I did note the following errors in the books print listed by chapter:

Chapter 5

Page 193, Paragraph 1, Sentence 4 and 5

The statement with regard to holddown timers and Routers running RIP routers is false. The statement read "If an advertised hop count is higher than the recorded hop count and the update was received was originated by the recorded next-hop router, the route will be marked as unreachable for a specified holddown period. If at the end of that time the same neighbor is still advertising the higher hop count, the new metric will be accepted". The reason this is wrong is because, a router that receives a route with a higher metric than the currently recorded metric and the advertising router is also the recorded next-hop router, the router will immediately install the new metric. (lab tested).

Appendix F

Page 970, Chapter 7, Answer 1

The given answer is not completely correct as stated. First the answer states that the router labeled C on page 321 and who's configuration is on page 324 will interpret the RIPv2 routes 192.168.90.0/29 and 192.168.13.86/28 coming from routers A and B respectfully as 192.168.13.64/27 and discards them because this route is directly connected to one of router C's interfaces. This is incorrect first because the routes that will be advertised by routers A and B will be 192.168.13.80/29 and 192.168.13.80/28 respectfully not 192.168.13.86/28 and 192.168.90.0/29. Secondly because router C is configured with the default rip settings, which allows the router to advertise RIPv1 and receive RIPv1 and RIPv2, which will allow router C to correctly interpret the masks sent with the RIPv2 updates sent by routers A and B as such router C will have both (Lab Tested).

Appendix C, Chapter 11, Answer 1

The answer as stated is not completely correct. The answer states that in order to redistribute between the IGP domain and the RIPv1 domain the router labeled B should have its mask changed from /27 to /28. Although this facilitates the routes from the IGRP domain into the RIPv1 domain it does not completely facilitate the reverse. The reason for this is that when router B receives the RIPv1 updates from router C it interprets those routes to have a /28 mask due to the new mask on its E1 interface. This results in the IGRP domain believing that the subnets in the RIPv1 domain have only 14 hosts per subnet where as they really can have as may as 30 hosts. In example take the subnet 172.16.2.32/27 which possibly contains hosts 172.16.2.33 -62 in the RIP domain, when this route is redistributed into the IGRP domain it would be interpreted to only contain hosts 172.16.2.33-46. This would cause packets originating in the IGRP domain destined for the hosts numbered 172.16.2.47-62 to be returned unreachable by the routers in the IGRP domain without further configuration. i.e. static routes.

I've just finished reading Jeff Doyle's "Routing TCP/IP Volume I" book and feel confident that I can now pass the CCIE lab in the near future. His presentation of TCP/IP IGP routing protocols is very clear and concise, with a perspective and insight into internetworking which is rarely encountered. This edition combines introductory, historical, conceptual and practical materials, and RFC's, with a first rate writing ability into one scintillating package.

The chapter on OSPF was particularly satisfying going into the depth where the next step would be research into the protocol. Having said that there is a very pragmatic side to this book including configuration examples within the text as well as configuration and troubleshooting exercises and review questions at the end of the relevant chapters.

By leaving nothing on IGP's out and all the while remaining emminently readable, this book marks a very welcome and refreshing addition to the internetworking literature and will no doubt become known as a seminal work. I truly appreciate what I have learnt from this book, and am very much looking forward to the publication of Jeff's next work on EGP's, in Volume II, in July.

This book is an exceptional reference for preparing for CCIE and for knowing Cisco IGP implementation, although, I assume many hands-on practice labs and work experience are also required in addition to it. It made my life easier, thinking that CCIE and expertise in IGPs are attainable. All chapters are great, especially OSPF, but I think redistribution and filtering wouldn't hurt to have more examples. I would suggest a second edition in order to cover features and commands added by Cisco, since the first one came out, increase its difficulty and add few more case studies and troubleshooting scenarios to complete it. This book is so great for the theoretical explanation of IGPs and not for their practical application. It would've been another 1000 pages to accomplish that. Actually, I think CiscoPress and Jeff should publish a book only with IGPs case studies, troubleshooting (real-world, basic, moderate and very difficult cases) and technical tips given the complexity of this information. Anyway, look no further! This is the world's number one book about Cisco interior routing protocols.