Table of contents (for this page):
If you could use some help with BGP, have a look at my business web site: inet6consult.com.
BGP routing coursesSeveral times a year I teach a hands-on BGP training course in association with NL-ix. The course consists of a theory part in the morning and a practical part in the afternoon where the participants implement several assignments on a Cisco router or a VM running the Quagga routing software.
The next dates are:
Interdomain Routing & IPv6 News
This is a post that I wrote for the Noction blog:
Like other very successful protocols such as HTTP and DNS, over the years BGP has been given more and more additional jobs to do. In this blog post, we’ll look at the new functionality and new use cases that have been added to BGP over the years. These include various uses of BGP in enterprise networks and data centers.
Recently, I've been looking a bit at BGP in datacenters, and it's really interesting to see how BGP is used in such different ways than it is for global inter-domain routing.
We shouldn't gauge the success of IPv6 by looking at how much IPv6 replaces IPv4, but by how much IPv6 complements IPv4. And it's already doing that quite well today by making IPv4aaS (IPv4 as a service) possible. And IPv4aaS will make ISPs require IPv6 when peering with streaming services and other big content providers.
As of a few days ago, IPv4 has run out in all regions in the world, as AFRINIC, the Regional Internet Registry that serves Africa, has now reached IPv4 exhaustion phase 2.
For more on the IPv4 exhaustion over the last decade, see my story The rise of IPv6 and fall of IPv4 in the 2010s.
My Books: "BGP" and "Running IPv6"On this page you can find more information about my book "BGP". Or you can jump immediately to chapter 6, "Traffic Engineering", (approx. 150kB) that O'Reilly has put online as a sample chapter. Information about the Japanese translation can be found here.
More information about my second book, "Running IPv6", is available here.
BGP SecurityBGP has some security holes. This sounds very bad, and of course it isn't good, but don't be overly alarmed. There are basically two problems: sessions can be hijacked, and it is possible to inject incorrect information into the BGP tables for someone who can either hijack a session or someone who has a legitimate BGP session.
Session hijacking is hard to do for someone who can't see the TCP sequence number for the TCP session the BGP protocol runs over, and if there are good anti-spoofing filters it is even impossible. And of course using the TCP MD5 password option (RFC 2385) makes all of this nearly impossible even for someone who can sniff the BGP traffic.
Nearly all ISPs filter BGP information from customers, so in most cases it isn't possible to successfully inject false information. However, filtering on peering sessions between ISPs isn't as widespread, although some networks do this. A rogue ISP could do some real damage here.
There are now two efforts underway to better secure BGP:
The IETF RPSEC (routing protocol security) working group is active in this area.
What is BGPexpert.com?BGPexpert.com is a website dedicated to Internet routing issues. What we want is for packets to find their way from one end of the globe to another, and make the jobs of the people that make this happen a little easier.
Ok, but what is BGP?Have a look at the "what is BGP" page. There is also a list of BGP and interdomain routing terms on this page.
BGP and MultihomingIf you are not an ISP, your main reason to be interested in BGP will probably be to multihome. By connecting to two or more ISPs at the same time, you are "multihomed" and you no longer have to depend on a single ISP for your network connectivity.
This sounds simple enough, but as always, there is a catch. For regular customers, it's the Internet Service Provider who makes sure the rest of the Internet knows where packets have to be sent to reach their customer. If you are multihomed, you can't let your ISP do this, because then you would have to depend on a single ISP again. This is where the BGP protocol comes in: this is the protocol used to carry this information from ISP to ISP. By announcing reachability information for your network to two ISPs, you can make sure everybody still knows how to reach you if one of those ISPs has an outage.
For those of you interested in multihoming in IPv6 (which is pretty much impossible at the moment), have a look at the "IPv6 multihoming solutions" page.
Are you a BGP expert? Take the test to find out!
These questions are somewhat Cisco-centric. We now also have another set of questions and answers for self-study purposes.
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