The Next Generation IP Network
Networks are evolving. Scalability, performance, reliability, security
and cost considerations are all driving fundamental changes in network
equipment, architecture and even the underlying protocols. Applications
are consistently increasing in their functionality and sophistication,
and these too are demanding additional capabilities from traditionally
passive networks. IPv6 certainly is a key element of the on-going network
evolution. IPv6s increased address space, improved security, simplified
configuration processes and its inherent support for mobile users are
all factors contributing to IPv6s inevitable dominance of the Internet.
However, it would be extremely shortsighted to assume that this will be
the only major change in network architectures over the next few years.
Instead, IPv6 will be one of several major new components of the next
Other new networking enhancements are taking place in parallel with the
development of IPv6. These include multicast routing, high availability
routing, and Multi-Protocol Label Switching (MPLS). Each of these new
paradigms significantly enhances traditional networks in its own way.
Each of these must also be acutely aware of the other concurrent changes
that are taking place to ensure that they are not disruptive to any other
evolutionary process. In particular, these new technologies must support
IPv6 in order to survive in the next generation of the Internet. Altogether,
these technologies represent the future of IP networks.
Network administrators have ignored the challenges associated with multicast
routing for years. Applications have recently emerged that are dependent
upon multicast communications. These applications include data casting
(stock tickers, news groups, sports scores, etc.), webinars, videoconferences,
games and simulations, and distance learning. This means that network
architects must now include multicast routing in all future designs and
The premier multicast routing protocol is known as Protocol Independent
Multicast Sparse Mode (PIM-SM). This protocol was designed at its
inception to be agnostic regarding IP versions. This is the only routing
protocol that transparently supports IPv6 without requiring any additional
updates or appendices. Furthermore, IPv6 was designed with multicast routing
in mind any IPv6 address that begins with ff designates a multicast
Multicast applications are proliferating, and have become a reality that
network architects must include in future network designs. Network modeling
and trial and error iterations will be necessary to optimize
this new type of traffic. While there is still a lot of uncertainty concerning
the impact of these new applications on network bandwidth and resources,
the good news is that the standards are already progressive enough to
fully embrace IPv6.
High Availability Routing
The term mission critical network is so overused that it has
become a cliché. Nearly all organizations have become entirely
dependent upon their data none more so than the Department of Defense,
or even ISPs, where the mission is the network. Downtime is
absolutely intolerable. It can be exceedingly costly in terms of lost
dollars, missed opportunities, and sometimes even actual loss of life.
As networks continue to expand (which is the main premise supporting the
migration to IPv6), downtime will become even less palatable.
Some fundamental design concepts for basic resiliency apply to all types
of networks. Redundant links and components will allow the network to
rapidly recover from some types of hard failures. Other problems
can be much more subtle, such as routing protocol fluctuations or software
glitches. These types of issues need to be addressed from a protocol level.
A couple of redundancy protocols have been developed in order to improve
network resilience. The Hot Standby Router Protocol (HSRP) and the Virtual
Router Redundancy Protocol (VRRP) both address the issues of redundant
components and rapid fail-over procedures. Both of these protocols are
designed to support equipment recovery, so they are applicable to all
higher-level protocols including IPv6.
Other protocols also have built-in resiliency features. For example, BGP
has a new extension known as graceful restart that facilitates rapid recovery
from a link or equipment failure. Other routing protocols have similar
extended feature sets. All of these extensions are already fully compatible
with IPv6, so the same benefits will be available for future networks.
Multi-Protocol Label Switching (MPLS)
A common complaint about IP networks (especially the Internet) is the
lack of any kind of quality of service. Nearly all IP networks are based
upon best effort packet delivery algorithms. Furthermore,
since IP networks are generally connectionless, packet paths may vary
for any given data stream. While the current mechanisms tend to be adequate
for most traffic, they are entirely nondeterministic with regard to latency,
throughput and even packet sequencing. This can be quite problematic for
time-sensitive applications such as audio or video conferencing.
The next generation of the Internet must offer a solution for quality
of service challenges. This solution will be based upon Multi-Protocol
Label Switching (MPLS). This is a streamlined communications mechanism
based upon the establishment of logical connections between the source
and destination of a data stream. This connection can support quality
of service attributes based upon the traffic engineering parameters that
the user specifies.
As the name implies, MPLS is a switching technology that utilizes a small
label that is pre-pended to an IP packet. The routers throughout the Internet
will switch this packet without incurring the latency associated with
traditional longest-match IP routing table look-ups. The reduced latency
and quality of service guarantees of MPLS are highly desirable for real-time
Service providers throughout the world are already starting to deploy
MPLS networks. The first deployments support VPN services for large enterprise
The standards for MPLS, MPLS VPNs, and MPLS QoS are still evolving. However,
in most cases, these standards already take into account the requirements
associated with migrating to the IPv6 protocol. In fact, some router vendors
already support IPv6 VPNs over MPLS.
The Next Generation Network
The next generation of the Internet or any other major IP network will
manifest several significant evolutionary changes. The scalability, performance,
reliability and functionality of future IP networks will all improve dramatically.
Many exciting new applications will be enabled over the new and
improved Internet. IPv6 will play a major role in this transformation.
However, IPv6 by itself cannot conquer all of these challenges. Instead,
IPv6 will need to work hand-in-hand with other new technologies. Fortunately,
these emerging protocols and solutions are not being developed in a vacuum.
Instead, these efforts are cognizant of each other, so that most interoperability
and compatibility issues have already been resolved. Together, these technologies
represent the future of IP networking.