Information Technology Reference
In-Depth Information
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Multiprotocol BGP Support
for IPv6
The IPv4 protocol suite was developed in the late 1970s and early 1980s. It was designed
for use in a moderately sized network. The network requirements of today are different
from when IPv4 was designed. It is not so much that these requirements have changed,
but that they have been increased because of the nature of the global Internet.
The primary goals during the design of IPv4 were to provide global reachability and fault-
tolerant traffic routing. The nature of the Internet creates a need to provide increased levels
of traffic differentiation for varying levels of traffic handling through quality of service
(QoS), enhanced security requirements, a larger address space, improved address adminis-
tration, and more efficient data handling in the forwarding path.
The IPv6 project began as an effort to resolve the potential for address exhaustion in the
IPv4 address space and developed into providing a foundation for the next-generation
Internet, capable of providing a worldwide communications and commerce medium. The
migration to IPv6 will be the most significant transition for the Internet and corporate
networks to date.
This chapter starts by covering IPv6 to provide a basis for understanding the BGP-specific
information. The primary enhancements of IPv6 over IPv4 are discussed, followed by a
look at IPv6 addressing. After a brief examination of IPv6 addressing, the BGP extensions
to support IPv6 network layer reachability information (NLRI) are covered, including
caveats that result from IPv4 information that is required for protocol operation. This
chapter concludes with a case study on IPv4 and IPv6 in a dual-stack deployment.
IPv6 Enhancements
The development of IPv6 is an evolutionary step from IPv4. The last 20 years have brought
to light a number of areas for improvement. The IPv6 protocol is very similar to IPv4 in
most aspects. The enhancements can be classified into the following general categories:
•
Expanded addressing
•
Autoconfiguration
•
Header simplification
•
Security
•
QoS
