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February 27, 2008
Session Management 2.0
By Sridhar Ramachandran, Co-Founder, Chief Technology Officer
Fixed and mobile operators have never faced as many challenges as they do now. They face increased competition from other service providers and Web companies, increased demand for new applications and services from subscribers, and a plethora of multi-modal devices that attach to their networks. Operators are under pressure to change their network infrastructure at an ever-increasing pace to keep up with those factors. Continually updating the network is capital inefficient, so operators are now applying techniques such as Session Management not only to make their networks more efficient, but also to lower capital and operational costs, while ensuring quality of service.
The Voice-Quality Argument
What is Session Management? Let’s look back to the ‘90s, when the broadband revolution was just beginning. Due to various technical and commercial reasons, voice — i.e., making phone calls over the broadband network — was an interesting and challenging application, and there was tremendous operator interest in leveraging it. We had many conversations with many network engineers and architects across the industry about what that meant. Initially, there was much skepticism about adding voice as an IP application. The usual arguments were that IP was best effort and that the industry had to invent a guaranteed “class-of-service” mechanism for IP voice to succeed.
The debate about “Voice over IP” versus “Voice over ATM over DSL” was often over maintaining the notion of a separate “pipe,” either virtual or physical, for voice, so that adequate quality could be guaranteed. While we saw the merit in that argument, the gut feel was that given the increasing speeds of broadband, as evidenced by new operator efforts to upgrade their network infrastructure to enable Fiber-to-the-Premise and other architectures, the problem was not in the access network. The issues that operators were going to face would be related to their core network infrastructure.
Voice Spurs Need for Session Management
As broadband networks evolved, the number of network applications and of subscribers grew many-fold. The number of sessions, which broadly speaking are just instances of applications reaching across the network, exploded, growing faster than the network infrastructure could keep up with — and leading to the “World Wide Wait” for many subscribers. Voice (both telephony and applications such as conferencing) was the first session-based application that showed the importance of session management. However, for the broadband infrastructure to carry voice, providing appropriate priority and quality for voice service was paramount. Security of the core network became a prime concern, as voice was multiplexed along with data. Operators could control the network-layer technologies in the broadband infrastructure, but could not extend control over session-layer components, creating many interoperability hurdles. The choice was to keep upgrading the core network or to manage the entry and egress points into the core network.
When a multiplicity of different devices started to attach to the network, the issues of security and interoperability became important. The edge of the core network needed the intelligence to sift through sessions, thwart security threats, improve interoperability with myriad devices, and honor the quality of service promised to the subscriber. The same issues also applied at the so-called “opposite” edge — where operators interconnect with other service providers and operators. (In this case, the quality of service is probably also expressed in a contractually binding service level agreement between the interconnecting parties.) The intelligence at the network edge is Session Management, and operators globally have deployed it and seen the benefits of employing it.
The Mobile Broadband Revolution
The fixed broadband revolution happened early in this decade, the mobile broadband revolution is just beginning. Mobile broadband provides a high-bandwidth pipe right to the individual’s mobile device or handset — it is really “personal broadband,” and it is beginning to empower the subscriber to use applications on the device and services over the network that operators have never seen before. A new set of devices, such as the iPhone (News - Alert), is also beginning to leverage personal broadband.
WiFi hotspots and enterprise WiFi (News - Alert) networks untethered subscribers and employees from fixed networks, and even though they may be available only in localized areas, the mobility they enable significantly empowers users. Today, most users tend to be nomadic, even though there is no handoff from hotspot to hotspot.
Mobile broadband technologies, such as HSDPA and EVDO, enable roaming and handoff from cell to cell over the wide area. This provides seamless connectivity for all the applications that the user chooses to run on the mobile device. We have already seen the effects of such mobile broadband technologies in email and browsers for mobile devices.
Session Management 2.0
While mobile broadband speeds may reach up to 2–3 Mbps today depending upon coverage, subscribers are supplementing their use of mobile broadband with WiFi and WiMAX for data-intensive applications. Since WiFi networks are connected to fixed-broadband networks, we see a subscriber dependence on all forms of broadband — fixed, nomadic, and mobile — that is leading to a convergence in user experience.
Operators now are faced with the challenge of dealing with different applications that are accessing their core network via multiple broadband access networks. Their earlier success with Session Management technologies has given operators the experience to see that similar technologies may be applied at the network edge for converged applications. Operators want Session Management 2.0 — session management that can handle the converging end user experience across both fixed and mobile access and across fixed, nomadic, and mobile applications.
Without session management, operators are faced with increasing complexities in their network. As more subscribers become mobile, the need for session management only increases and adding more applications implies that the infrastructure has to change. Session Management 2.0 is all about making the edge of the network more resilient and reliable so that the core network can adapt and add new capabilities and services that subscribers demand.
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Internet Protocol (IP) | X | | IP stands for Internet Protocol, a data-networking protocol developed throughout the 1980s. It is the established standard protocol for transmitting and receiving data
in packets over the Internet. I...more |
802.16 (WiMAX) | X | | As a sister technology to Wi-Fi, the IEEE 802.16 specification outlines technology for Wireless Metro Area Network (MAN). WiMAX actually stands for Worldwide Interoperability for Microwave Access, whi...more |
High Speed Downlink Packet Access (HSDPA) | X | | High Speed Downlink Packet Access was released in 3GPP-Third Generation Partnership Project Release 5 for indoor and urban outdoor high speed data access at 10 MBPS-Mega Bits Per Second range (14.4 MB...more |
Asynchronous Transfer Mode (ATM) | X | | ATM is a �fast cell� - connection-oriented digital data communications transport protocol. It uses fixed length data �payload� of 48 bytes/octets (octet is the international term for byte) plus 5 octe...more |
Wireless Fidelity (WiFi) | X | | The IEEE 802.11 wireless LAN standard is usually referred to as Wi-Fi-Wireless Fidelity or RLAN-Radio Local Area Network. The 802.11 standard has evolved into a number of sub-standards 802.11a/b/g/n....more |
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