February 2014
Intermediate to advanced
360 pages
7h 45m
English
book
Versatile Routing and Services with BGP: Understanding and Implementing BGP in SR-OS
by Alcatel-Lucent, Colin Bookham
Content preview from Versatile Routing and Services with BGP: Understanding and Implementing BGP in SR-OSBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Chapter 6
Reconvergence
The time to reconverge upon change and/or network failure has become an important factor in the delivery of business services. Historically, BGP was intentionally slow to reconverge as a way of avoiding route oscillation between Autonomous Systems. However, the requirement is now frequently to deliver sub-second reconvergence times because of the real-time nature of traffic being carried through Layer-3 and Layer-2 VPNs. This has meant changes not only in the speed with which BGP reacts to failure, but also changes in the protocol to allow for increased path visibility between BGP speakers. This chapter discusses some of the more notable changes.
Advertisement of Multiple Paths
Advertisement of Multiple Paths (ADD-PATH) is an extension to BGP that allows for advertisement of multiple paths for the same prefix/NLRI. This allows for upstream propagation without subsequent advertisements replacing earlier ones by an intervening BGP speaker's path-selection process. The purpose is to reduce route oscillations, enable load-balancing, and improve routing convergence by making an alternative path immediately available to a reconverging router.
To achieve this, each advertised path is identified by a 4-octet Path Identifier. To carry the Path Identifier in the UPDATE message, the NLRI encodings are extended by prepending the Path Identifier field. The combination of Path Identifier and prefix thereafter identifies a given path. Assignment of Path Identifier values ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.