What's SIP Got To Do With It?.doc


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What's SIP Got To Do With It?.doc

  1. 1. What’s SIP Got To Do With It? Five Compelling Reasons Why SIP Will Dominate Enterprise IP Telephony WHITE PAPER Introduction Technology advances are driving significant investment in the development and deploy- Recent LAN and WAN technologies ment of more reliable and high-performance make voice sound good. LANs. This momentum helps maximize the reliability and audio quality of IP telephony Since 1998 when 3Com brought to market implementations and create solutions to the first IP PBX, the enterprise Voice over match the cost expectations of enterprises. IP (VoIP) phenomenon has changed not just telecommunications, but also enterprise networking. The 3Com® NBX® system 2005—the Year of VoIP ushered in a new era of communications. 2005 is a fundamental turning point for the For the first time, companies were able to IP telephony industry. For the first time, leverage their investments in high perform- more IP-PBX ports will ship in the United ance local area networks (LANs) to deliver States than legacy digital ports . This is a real-time services such as IP telephony. major milestone, indicative of the reliability and audio quality now available in IP In fact, the major standardized innovations telephony services. The discussion of “if ” in Layer 2 switches and enterprise routers in users will migrate to IP telephony is now the past five years—virtual LAN (VLAN) “when” and with what strategic urgency. segmentation, packet prioritization, Power over Ethernet (PoE), differentiated services, Classically, the year of inflection represents multi-protocol label switching—enhance an acceleration of the pace of growth in the CONTENTS converged networking and its delivery market. In the case of IP telephony, this of high-quality audio. accelerated growth is occurring now for Introduction....................................................1 two primary reasons: • VLAN segmentation separates voice Recent LAN and WAN technologies traffic from e-mail uploads, web surfing, make voice sound good.............................1 • Depreciation schedules—equipment and database interactions purchased in preparation for Y2K is being 2005—Year of VoIP ........................................1 • Packet prioritization techniques enable retired now, enabling new purchases The Importance of Session Initiation higher priority for voice packets than • Large enterprise needs—emerging busi- Protocol in Enterprise IP Telephony .................2 other applications so that jitter and delay ness requirements necessitate enhanced, are minimized or eliminated cost-effectives services, already enjoyed SIP is simple. ..............................................2 • PoE enables a combination power- by small businesses with IP telephony SIP is secure. ..............................................2 and- communications cable to deployments minimize the required number of SIP is a standard. .......................................3 The value proposition for IP telephony is 120V power ports SIP applications abound. ............................3 moving beyond cost reduction-oriented • Differentiated services and Multi- business cases, to a framework of “conver- SIP is used by enterprises Protocol Label Switching (MPLS) enable gence applications” that offer advantages and carriers................................................3 prioritization for voice packet streams difficult to accomplish with legacy telephone and rapid transit across IP wide area Summary ........................................................4 implementations. Applications—such as IP networks (WANs) messaging—can broadcast voice mail and Enhancements to the wireless LAN envi- deliver voice mail as e-mail. IP conferencing ronment through the auspices of the IEEE can provide audio, video, and data confer- 802.11 committees also facilitate high encing services. IP contact centers offer quality IP telephony services. Recently freedom from the geographic constraints of ratified specifications for Quality of Service legacy solutions. IP mobility solutions that over the air (802.11e) and privacy services provide on-campus voice and data services (802.11i) address many of the same issues via wireless LANs are proving themselves being addressed by other 802.1 committees. critical for business productivity and customer interactions. 1
  2. 2. 3C OM ® WHAT ’ S S I P GO T T O DO W IT H IT? W H IT E PA P E R The Importance of Session In civilization and in nature, simple has been proven to be both useful and enduring. Initiation Protocol in For example, the sphere and its derivatives Enterprise IP Telephony are frequently occurring shapes in fruit and celestial objects as contrasted to the more If indeed applications are the driving force complex pyramid. The steering wheel, rather behind IP telephony implementations, what than the handle bar, is used in automobile will be the key enabler of enterprise applica- control designs. The flat CD replaced the tions, enterprise applications developers, more complex floppy disk cartridge design as and integrations into existing enterprise the definitive media storage framework. applications? Years ago, a wise man once explained why It is the premise of this white paper that Asynchronous Transfer Mode (ATM) was Session Initiation Protocol (SIP) will fill that going to destroy a carrier service of interest to need. the phone companies at the time—Switched Multi-megabit Data Service (SMDS)—that SIP is simple. was a connectionless ATM-type service. Two Session Initiation Protocol (SIP) Using the Internet Engineering Task Force arguments were given for his assertion. First, SIP was developed in 1999 as a media and (IETF) fundamental of technology reuse and ATM was simpler (notice three-letter application independent session control the proven value of simplicity, the SIP acronym versus the four-letter acronym). protocol by the Internet Engineering Task message set is quite an elegant construction— Second, six messages that appear in clear text to facili- ATM didn’t require a phone company to Force, the same people and process developers tate call setup. Clear text allows for easy implement the technology, resulting in ATM that manage all important Internet protocols troubleshooting and avoids complex soft- having a larger addressable market that like ware interactions and other processing that could provide ample opportunity for solving IP, FTP, TLS, and HTTP. SIP is denoted as RFC affect interoperability. The six messages are business problems (relevance). 3261, which defines the messages, options, Invite, Trying, Ringing, OK, ACK, Bye. and protocols at the heart of SIP. SIP is secure. SIP is both elegant and practical. Its base Learn more at: assumption is that all SIP endpoints and There are tradeoffs between interoperability elements exist in the IP environment, an and cost when considering security. Simple www.3com.com/voip/sip.html or standards make it easier to interoperate within www.ietf.org/rfc3261.html arena already equipped with standard mech- anisms to handle packet transport priorities, a multi-vendor network, but they also expose privacy, and other required services. These the network to potential abuse. This vulner- value-added services do not require specifi- ability, however, can be effectively addressed cation in the SIP framework. Whereas, in by strong authentication and privacy services. legacy environments such as the public tele- that do not interfere with the primary busi- phone network the use of hyper-text transport ness benefit of standard-based solutions and protocol (http) is neither integral or readily also enable a long investment life through available. interchangeable vendors, services, applica- tions, and devices. This “building block” approach on an IP base is unique to IETF initiatives. The results The IETF framework for SIP offers a rich set are nearly trivial protocol definitions such as of standards for authentication and privacy, SIP in contrast with older session control or including secure SIP, secure RTCP, and secure interface protocols such as H.323 or Q.SIG RTP. These capabilities leverage IETF from the International Telecommunications proposals for the use of standard Union (ITU). These older, telecom-centric implementations such as Transport Layer protocols have considerably more Security (TLS) for robust complex definitions as shown in Table 1. session privacy service and Secure/Multi- part Internet Mail Extensions (S/MIME) for session control packet privacy. TA BLE 1: C ont r as t bet wee n ke y S I P at t r ibut e s an d H . 323 si gnal i n g p r o to co l s. [ Sou r ce: B us in e s s C om m unic at ions R ev ie w, Oc to b e r 2 00 4] ATTRIBUTE H.323 SIP Design Complex Simple Standard 736 pages 128 pages Number of elements 100s 37 Messages Based on ASN.1 HTTP and RTP Call Setup 23 steps 5 steps Extensibility Designed for LAN Designed for IP Large Phone number domains Limited Open to all sizes Firewall Support Difficult Easier
  3. 3. Interoperability among vendors Poor Good 2
  4. 4. 3 C OM ® W HAT ’ S S I P GOT T O D O W IT H IT ? WH IT E PA P E R Most vendors implementing H.323 offer no Program as an initiative to encourage SIP- such options. Instead, they choose to imple- based interoperability. A list of more than 30 ment proprietary derivatives to facilitate vendors, service providers, and solutions rudimentary forms of privacy in first gener- that are proven to interoperate with 3Com IP ation IP-PBX devices. This approach is telephony modules is available at: typical of the PBX vendor solutions brought www.3com.com/voip/interoperability.html to market during the past two decades in which proprietary digital signaling protocols SIP applications abound. were implemented on endpoints and PBX Internet search engines can be an amazing fabric. The result of these decisions was proxy for markets and issues. Their objective nominally-better security, but considerably is to scour the Internet, capture prose, process more vendor-specific lock-in that failed to whatever they find, and quickly present it provide many useful features—such as call to users with some rank ordering that forward and hold—at a standard service level. approximates users’ views of relevancy. Google, in particular, is an effective measure SIP is a standard. of ”buzz” because of its contentpresentation Despite being a standard, SIP implementa- in terms of users’ views of relevancy. tions do vary. Some vendors, most notably legacy TDM-based PBX vendors and first Figure 2 shows the contrast between the generation IP telephony vendors who built number of references found by the Google their products around H.323 or around search engine for “SIP applications”, “H.323 proprietary protocols, offer SIP interoper- applications”, and “Cisco Skinny Call Control ability as an interface into their otherwise Protocol.” In this analysis, the presence of non-SIP telephony system. This approach open, simple (SIP) references clearly out- helps the vendor maintain account and paces references for open, complex (H.323) feature control. They can charge extra for and proprietary applications. End users are SIP support for only the most rudimentary recognizing the enormous flexibility and features while offering advanced premium- value of SIP. priced feature options with their proprietary call control protocol and implementation. SIP is used by enterprises and carriers. Since SIP transcends carrier/enterprise Alone among the leading IP-PBX vendors, boundaries, it can attract applications devel- 3Com has implemented a different approach. opers able to deliver their core applications Using standard SIP among endpoints such as technologies in a variety of value packages IP phones, video cameras, call controllers and to address a range of financing models and gateways to the public telephone network, and markets. For example: 3Com SIP-based solutions enable a robust • The stand-alone enterprise market, and inexpensive, vendor-neutral environment, addressed by direct sales or resellers capable of rapidly delivering a portfolio of cutting-edge applications for presence, confer- • The stand-alone consumer market, addressed encing, contact center, messaging, and by retailers, online or direct marketers mobility services. Furthermore, 3Com is a • The hosted service model, sold to carriers founding member of the SIP Forum and but billed to enterprises in monthly charges promotes the 3Com Voice Solutions Provider FI GUR E 2: T h o u s a nd s o f r e fe r enc e s on Google. c om , Januar y 20 05 . 1400 1200 1000 800 600 400 200 0 SIP Applications H.323 Applications Skinny Call Control Protocol Applications 3
  5. 5. 3 C OM ® W HAT ’ S S I P GOT T O D O W IT H IT ? WH IT E PA P E R • The hosted service model, sold to carriers Summary but billed to consumers in monthly charges • The stand-alone enterprise market, As demand for IP telephony and SIP services 3Com has been a major contributor to the addressed by carrier enterprise equipment and implementations continues to accelerate, convergence industry since it brought to sales organizations the public telephone network faces change. market the NBX IP-PBX in 1998. It developed A mainstay of the global economy for the This multi-market model provides ample past ten decades, it is losing ground to a an architecture for a distributed softswitch for space for initial focus. Depending on vendor network of world-wide IP communications AT&T and introduced it in the first commer- strengths and skills, the model supports integrated with simple, secure, standards- cially deployed carrier softswitch in 1999. based, applications-rich implementations considerable opportunity for both startup Then in 2003, the 3Com VCX™ solution and established developers. and services. became a key component of the world’s first convergence applications suite. Maintaining Since SIP is used by enterprises and carriers There can be little doubt of the important role its leadership position, the company is also a across multiple markets, carriers can offer that SIP will play in facilitating this transition innovative services aimed at enterprises. For and enabling powerful enterprise applications founding member of the VoIP Security Alliance. example, SIP trunking services allow two that reduce cost, improve user productivity, Transforming business through innovation is SIP-empowered enterprises to communicate and strengthen customer interactions. Some not new to 3Com. It holds over 1,600 patents using RTP from endpoint to endpoint without vendors will be slow to appreciate and take and is the market leader in IP telephony for the need for a gateway between them. The advantage of this opportunity. They may small to medium enterprises. It operates in growth of this category of services is helping focus their energies on attempting to retrain reduce costs by lowering the load on packet- the transition rather than exploring its over 45 countries with approximately 1,900 circuit gateways and reducing regulatory possibilities. employees. and tax burdens. 3Com embraces innovation and standards. 3Com: we’re changing the SIP trunking also improves audio quality They are a foundation on which the company since bandwidth allocation can be negotiated builds business-enhancing solutions. The way business speaks. end-to-end instead of end-to-gateway-over- question is no longer why, but when will SIP digital-to-gateway-to-end. Fewer digital be integral to every business’ future? hops with more bandwidth enables wide- band audio quality, as well as SIP-initiated video conferencing. 3Com Corporation, Corporate Headquarters, 350 Campus Drive, Marlborough, MA 01752-3064 To learn more about 3Com solutions, visit www.3com.com. 3Com is publicly traded on NASDAQ under the symbol COMS. Copyright © 2005 3Com Corporation. All rights reserved. 3Com, the 3Com logo and NBX are registered trademarks of 3Com Corporation. VCX is a trademark of 3Com Corporation. All other company and product names may be trademarks of their respective companies. While every effort is made to ensure the information given is accurate, 3Com does not accept liability for any errors or mistakes which may arise. Specifications and other information in this document may be subject to change without notice. 503153-001 07/05