Appendix B. Additional QoS Reference Materials

A few years ago, Cisco introduced a couple of different QoS courses, along with a couple of different QoS exams, called DQOS and QOS. The two exams had about 60 percent overlap with each other, but the DQOS exam and course focused more on Enterprises and VoIP, whereas the QoS exam and course focused more on QoS issues in Service Provider networks.

To support the exams, Cisco Press also came out with the first edition of this book, which focused on the DQOS exam, but included coverage of most of the topics on the QoS exam that weren't also on the DQOS exam.

Later, mainly early in 2004, Cisco changed to have a single QoS course and exam (642-642). The two courses essentially merged, with some topics being removed, and with several new topics being added. Also, topics that were in the older courses were updated based on the Cisco IOS Software Release 12.2T/12.3 revisions.

Personally, I think Cisco definitely had the right idea with the update to the new QoS course and exam. The course and exam focus on the most appropriate QoS tools today, at least when running the latest IOS releases. So, for people just looking to build skills for today's new networks, the scope of the topics on the exam is well chosen.

However, for a couple of reasons, we decided to include several topics from the First Edition of this book in an appendix. The first reason is that a lot of CCIE Route/Switch and CCIE Voice candidates had been looking for a good QoS book to use to study for their labs, and the materials in the First Edition were popular with those folks.

Another justification for the inclusion of this appendix is that a few topics are good background for people deploying QoS in real networks. According to Cisco's website, Cisco IOS Software Release 12.2 reached General Deployment (GD) status in February of 2004. Some customers tend to wait on GD status before migrating to a new IOS release. So, for partner engineers, some customers simply won't be able to take advantage of some of the newer QoS features. So, this appendix might be a nice reference.

Finally, we wanted to keep the FRTS configuration section around. The current QoS exam (642-642) does not cover Frame Relay Traffic Shaping (FRTS) as an end to itself, but it does cover FRF.12 Fragmentation[md]which requires FRTS. This appendix provides a little more background on FRTS.

Finally, a word of disclaimer. The topics in appendix were taken from the first edition of this book, which was based on features available with Cisco IOS Software Release 12.1(5)T. for the most part. We did not update these topics based on later IOS releases. We offer this appendix for those people who might find it useful, but please be aware that it is outdated compared to the later IOS releases. In fact, there may be a few cases where this appendix contradicts the core chapters in the book because of those changes; when in doubt, trust the core chapters, and not this appendix, in regards to the QoS exam.