January 2002
Beginner
238 pages
6h 20m
English
Content preview from IP RoutingBecome 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 7. Border Gateway Protocol 4 (BGP-4)
My first passport, issued by the Government of India in 1981, bore a curious stamp in bold red ink on one of its first pages: “NOT VALID FOR TRAVEL IN THE REPUBLIC OF SOUTH AFRICA.”
Toward the end of the 1990s, I was traveling through Europe with a U.S. passport. Upon landing at Schiphol Airport in Amsterdam, I was stopped by an officer and led to a small room off to the side. There, I was made to remove my left shoe and sock. The officer checked my sock carefully before letting me go. Once I had cleared Dutch customs, I freely roamed up and down that beautiful country, walking barefoot over grass and flowers, past windmills.
Nations have policies concerning who can pass through their borders. So, India did not permit its citizens to grace the Republic of South Africa during its reign of apartheid. And the Dutch bar entry into their country if your left sock is not fresh and clean.
What does all this have to do with internetworking, or BGP-4, for that matter? Each network is an autonomous system (AS) managed by a single technical entity and under one political administration. ASs are akin to nation states. Much as nation states apply their immigration policies at international airports, seaports, and land border points, the Internet is composed of ASs that use Border Gateway Protocol 4 (BGP-4) to implement inter-AS IP routing policies.
What is a routing policy? Consider the topology in Figure 7-1. TraderMary has two links to the Internet: ...
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.