Another free chapter download is available on the IT Bookworm Blog.
Written by: Mobeen Tahir, Mark Ghattas, Dawit Birhanu, Syed Natif Nawaz
Book: Cisco IOS XR Fundamentals
Overview: "Cisco IOS XR Fundamentals is a systematic, authoritative guide to configuring routers with Cisco IOS XR, the next-generation flagship Cisco Internet operating system. In this book, a team of Cisco experts brings together quick, authoritative, and example-rich reference information for all the commands most frequently used to configure and troubleshoot Cisco IOS XR-based routers in both service provider and enterprise environments."
Download the free chapter at the link below:Chapter 6: Cisco IOS XR Security