The Next Generation IP Network
Bill Kine, Product Manager, Spirent Communications

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. IPv6’s increased address space, improved security, simplified configuration processes and its inherent support for mobile users are all factors contributing to IPv6’s 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 generation networks.
 
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.
 
Multicast Routing
 
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 plans.
 
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 group.
 
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 applications.
 
Service providers throughout the world are already starting to deploy MPLS networks. The first deployments support VPN services for large enterprise customers.
 
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.