Cloud Native Data Center Networking

Chapter 14. BGP in the Data Center

Would it save you a lot of time if I just gave up and went mad now?

Douglas Adams

BGP is like a mythical beast: respected but also greatly feared. From its birth in 1989 as the replacement for a routing protocol called the Exterior Gateway Protocol (EGP) to the present, BGP has evolved into a sophisticated, mature, rich (and therefore, some would say, complex) routing protocol, which still is responsible for piecing together the internet as we know it today. Besides this, it has been applied to solve routing in new areas (the data center) which are far from its roots. Furthermore, it has also morphed to support new ideas such as SDN controllers. To its detractors, Douglas Adams probably perfectly captures their sentiments about understanding BGP.

I’d like to save you a lot of time not going mad. So, we begin with a brief overview of only those basic BGP concepts that are required to understand its use inside the data center. After that, we examine the specific adaptations to make BGP work in the data center. This chapter is a concise introduction to the protocol. Readers interested in more details are welcome to peruse either the standard or other books on the subject matter.

By the end of this chapter, a reader should be able to answer questions such as these:

• What do the BGP terms such as ASN, community, attribute, and best path mean?

• Should I use eBGP or iBGP in the data center?

• What is the ASN numbering scheme when using BGP in the ...