Expanding the role of the IP router to meet growing network demands
Michael Kennedy, ACG Research
A decade ago IP networks provided access from fixed locations to mail systems and static information sources. Today IP networks provide access to a wide range of personalized, socially-inclusive, media-rich apps. Access devices, furthermore, have expanded from PCs to a dramatically expanding range of devices including smartphones, HDTVs, game controllers, smart grid transponders, and healthcare monitors. The role of the IP router must necessarily expand to meet these changing network needs.
IP networks are changing in many ways. Long predicted, the convergence of all services onto a single IP network is now occurring. Voice (VoIP), video (IPTV and video streaming), enterprise data communications, and the Internet itself are now running on a single network. Cloud-based applications are overtaking traditional server-based applications. Network usage is becoming personalized and mobile--there are now more user endpoints and they are more transient. End-user devices are proliferating in number and form and media-rich content is used on most of them.
The changing network presents challenges to network designers and operators. Existing overlay networks are too complex and expensive--simplification is needed. Flatter architectures are required. Common core and transport networks are needed as is a converged network edge. The number of network nodes and network segments must be reduced. Less use should be made of encapsulation techniques and end-to-end management is needed.
Network convergence requires a transition to flow-based routing to assure that the particular quality and performance requirements of each service are met. This requires converged policy, unified subscription, and traffic control. Also, traffic routing must be optimized. Subscriber management including session management, authentication and authorization, QoS control, and billing functions.
These requirements change the scale of underlying signaling requirements. Signaling requirements are increased further by cloud computing, mobile apps, mobility itself, and device proliferation.
Traffic growth also is rapidly expanding alongside the growth in signaling requirements. Media-rich applications require orders of magnitude more bandwidth than legacy text-based applications. In addition, the movement from broadcast video to personalized video drives a dramatic bandwidth increase. Broadcast video is multicast to subscribers simultaneously, whereas personalized video (OTT video) is unicast to each subscriber separately. Ericsson estimates that global traffic will grow 39 percent while Cisco (Nasdaq: CSCO) estimates 32 percent annually over the next five years.
Service providers' dilemma is that revenue is not growing anywhere near 32-39 percent per year. Consequently, IP routers and other network infrastructure must have declining unit costs ($/bps) for service providers' profits to be maintained. (Infrastructure must be scalable.)
The IP router must necessarily evolve to meet these new requirements if it is to retain its role as the primary engine driving IP networking. Its evolution is following the classic electronics industry pattern of incorporating more functions into a single chassis or even onto more extensively integrated chips. Specifically, applications processing blades are being added to router chassis to accommodate a wide range of monitoring, control and policy functions. These onboard processing blades take the place of multiple chassis (appliances) that support value-added functions. This improves network performance and reduces cost. At the most basic level the router's high speed backplane handles packet flows among the various applications, whereas the use of standalone appliances ties up router line card ports to support the associated packet flows. Elimination of these back-to-back port interconnections yields performance improvements, reduces capex and opex, and reduces the network's carbon footprint.
Network Address Translation (NAT), firewall, load balancing, and flow monitoring are some of the functions that are being brought onboard IP routers. The need for more IP addresses is driven by the proliferation of end user devices and increased network mobility. Network mobility requires more IP addresses because sessions are transient in a mobile network whereas fixed broadband network addresses remain static for months or years. IPv6 is needed to meet the demand for additional addresses. However, IPv4 is firmly entrenched in network designs. Therefore, Network Address Translation will be essential for sustaining IP networking operations for many years.
As IP networks provide advanced functionality like cloud services and support mobile apps stateful firewalls and intrusion prevention systems (IPS) are needed to deliver the trust levels users require of network-based applications. Integration of these functions into the router provides the performance and scaling needed for large scale applications. Load balancing which is needed to assure service response times and the necessary economic efficiency also benefits from integration into the router.
In addition, flow monitoring is needed to assure the differentiated quality requirements of converged services including voice, video and cloud services.
The switch/router's primary role of switching and routing packets is still vitally important and this must be done at ever increasing scale. However, scale increases are controlled by Moore's Law. It is hard for router vendors to sustain a competitive advantage by simply building bigger faster routers. Furthermore, much of the router's value is derived from the software applications that reside on the router's processor blades. These applications are too diverse and specialized for one vendor to do it all alone. Consequently, success in the router market depends increasingly on a router vendor's systems integration skills to assess each customer's needs and met them with the best combination of router hardware and network applications software.