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Energize your Unified Communications with SIP


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In a hyperconnected economy, businesses need tools that empower employees to work together and get more done, anytime, anywhere, using the devices they prefer. SIP Trunking enhances mobility and presence, and provides end-to-end unified communications applications, among other advantages. This paper explains how companies can simplify company-wide business communications using SIP-to energize communications, productivity, collaboration, and business growth.

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Energize your Unified Communications with SIP

  1. 1. Energize Your Unified Communications with SIP WHITEPAPER | Dr. Steven Shepard, Ph.D
  2. 2. Energize Your Unified Communications with SIP XO Communications 2 Table of Contents Abstract 3 Introduction 3 What Makes SIP so Popular? 3 What the SIP Signaling Protocol Does 4 The Way Workers Want to Communicate 4 SIP Advantages and Applications 5 1. Intelligence at the Edge 5 2. SIP Is Part of the Overall IP Suite 5 3. Supports Any Network Transport Medium 5 4. Mobility and Presence Support 6 5. Virtual Numbers 6 6. Business Continuity and Disaster Recovery 6 7. Supply Chain Support 7 8. Unified Communications Applications 7 Cost Benefits of SIP Trunking 8 SIP Trunks 8 Reduced Network Service Costs 9 Eliminating PRI Trunks and IP Conversion Devices 10 Evolutionary Migration Path 10 Considerations for Implementation 10 Interoperability 10 Security 10 E911 Requirements 11 Conclusion: Making the SIP Decision 11 The XO Advantage 11 About Steve Shepard 12 Appendix 13 About XO Communications: 14
  3. 3. Energize Your Unified Communications with SIP XO Communications 3 Abstract For IT decision makers in medium to large- sized businesses, this white paper presents an overview of the Session Initiation Protocol (SIP) standard, business applications for SIP trunking, and the advantages of SIP as an enabler for unified communications. Introduction Imagine having secure access to work-related content anytime, anywhere in the world, on any network, using any access device over any access technology? Would that not simplify life dramatically, and make the use of the network more efficient and relevant? Yes. This is becoming the reality today. The evolution of SIP, SIP’s impact on real-time unified communications, and its ability to simplify mobility have helped make SIP the choice for modern communications networking for businesses. What Makes SIP so Popular? Three phenomena made the evolution to SIP possible: 1. Inevitable, steady migration of content from the hard drive on the worker’s desktop or laptop computer to storage located within the network—either managed by the network provider or hosted by the enterprise. 2. The growing proliferation of Unified Communications (UC) technology in the workplace, including IP telephony, unified messaging, instant message/chat, texting, presence, conferencing, video chat, as well as support for Internet Protocol (IP) protocol applications across different devices. 3. The extension of the Internet Protocol as an application-layer, signaling protocol in the network infrastructure. SIP enables IP-based Unified Communications applications to be extended from IP-PBX systems, and/or an IP network across different network transport services and worker devices. In essence, it allows any worker on any network to have access to any content on-demand, irrespective of the worker’s location, device, or type of network access. SIP enables IP-based Unified Communications applications to be extended from IP-PBX systems, and/ or an IP network across different network transport services and worker devices. In essence, it allows any worker on any network to have access to any content on-demand, irrespective of the worker’s location, device, or type of network access.
  4. 4. Energize Your Unified Communications with SIP XO Communications 4 The Way Workers Want to Communicate Today, mobile access reigns as the preferred mode of connectivity as employees demand to use their own smartphones and laptops for work-related activities. For this reason, many communications service providers, including XO, have added mobility support for unified communications through downloadable applications. These types of applications can spur innovation and productivity among workers and eliminate the need for IT to provide company- issued mobile phones with separate calling plans. The three phenomena that made the evolution to SIP possible—migration of content, growing use of unified communications, and the extension of the Internet Protocol–enable: • Increased productivity through improved support for distributed workforces • Timelier and high quality responsiveness to customers, and • Reduced capital expenses (CAPEX) and operating expenses (OPEX) for networking infrastructures. SIP helps reduce the cost of networking, and SIP trunks free businesses from being locked into a specific network provider, now and in the future. Add the productivity and customer service benefits of a SIP network with Unified Communications—and it’s easy to see why the use of SIP technology is so compelling, and quickly rising in popularity among forward-thinking businesses. What the SIP Signaling Protocol Does As an application-layer protocol, SIP can establish and manage: • Two-party, multiparty, or multicast sessions • Internet telephony • Distribution of multimedia content • Management of multimedia conferences SIP is designed to be completely independent of the transport layer and can operate over the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), or the Stream Control Transmission Protocol (SCTP). SIP-based devices can use TCP or PDP protocols to connect to SIP servers.
  5. 5. Energize Your Unified Communications with SIP XO Communications 5 SIP Advantages and Applications When deployed in a network, SIP offers distinct advantages that can be used to develop powerful worker applications. For example: 1. Intelligence at the Edge SIP-enabled telephony systems offer most of the call processing and feature invocation procedures offered through traditional voice networks — but in a different way. Traditional voice networks use a hierarchical, centralized, core-based protocol designed around the limited requirements of telephone sets — which have no innate intelligence. SIP, on the other hand, is a peer-to-peer protocol, which requires a different type of network core infrastructure (preferably MPLS built on an IP platform) with a blend of intelligence located at the edge (i.e., software or end-user device hardware or PBX), complimented by more scalable, granular, and rapidly deployed services offered by service providers. 2. SIP Is Part of the Overall IP Suite As part of the overall IP suite, SIP is flexible and extraordinarily dynamic. Its functionality can be extended to any number of applications, including enhanced signaling for value-added services, VoIP, and XML-tagged applications. Because XML is used to structure, store, and send information across the network, it works well with SIP in environments where data needs to be retrieved and used, as in a contact center environment where customer records must be accessed, or in a healthcare environment where access to customer data is critical. As a “lightweight, text-based protocol,” SIP relies on a text-based command structure that uses the now universally familiar HTTP syntax and URL addressing, both ideal for delivering telephony over an IP network where the logical integration of applications (e.g., voice, messaging, conferencing, and Web access) can create an enhanced user experience. 3. Supports Any Network Transport Medium Because SIP is an application layer protocol, it can ride seamlessly across any transport scheme and be transported across any access type — cable, DSL, private line, Ethernet, and wireless. Thus, SIP can enable a broad range of applications and remote session capabilities (such as mobile application delivery and supply chain management) without the need to provision additional transport services. From an enterprise point-of-view, this is critical because SIP offers seamless connectivity options for service delivery for branch locations, remote workers, or business partners.
  6. 6. Energize Your Unified Communications with SIP XO Communications 6 4. Mobility and Presence Support SIP is now incorporated into a range of worker devices, including smartphones and laptops. Using SIP, session establishment requests aren’t sent to a device; they are sent to the network. The network locates the worker’s “presence” and establishes a session based on the user’s current location and usage profile. Employees can collaborate with coworkers, and enjoy integrated, real-time communications, wherever they are. Figure 1. A customer wants to get back in touch with a specific agent in a contact center, and places a call to that agent (yellow arrow, lower right). Since the agent is out of the office, SIP routes the call to the agent’s remote location (blue arrow, lower left), thus avoiding an interruption in customer service. To the customer, it appears as if the agent has answered from the office, which further projects a consistent experience and professional image. 5. Virtual Numbers A fifth advantage is the ability to utilize virtual numbers, an assignable telephone number that has no physical phone line associated with it. In most cases, virtual numbers are forwarded to either a VoIP account or to an alternate fixed or mobile number. For example, virtual numbers are perfect for sales forces, business travelers, small businesses, and field service personnel. With virtual numbers, businesses can also create a local identity in markets that the company serves. 6. Business Continuity and Disaster Recovery SIP trunks, in concert with VoIP, can play a major role in business continuity and disaster recovery. With a SIP-supported IP-PBX, many businesses are now able to design disaster recovery plans using plug and play phones, softphones, and IP-PBX programmability capabilities. Automatic reroute in IP environments is possible, thus reducing the headache of planning for every contingency. For businesses of any size, SIP trunks provide connections to the PSTN so that outbound calls can be rerouted and delivered over an Internet connection when the normal connection (or location of the connection) is unavailable.
  7. 7. Energize Your Unified Communications with SIP XO Communications 7 Unified communications applications exist that are already integrated with SIP and VoIP services. These applications automatically route calls to workers’ smartphones so that they can continue business as usual even in the event of a disaster. In addition, business-class service providers build multiple layers of redundancy into their networks to provide for business continuity. A carrier should provision network session capacity to support failover of traffic between designated sites. Service providers also should track session usage for each of their customer’s sites and implement a primary/backup arrangement to manage overflow traffic. When sessions in one site are fully used, the network automatically routes inbound traffic, normally delivered to the first site, to the second site. 7. Supply Chain Support The overall supply chain is enhanced when executed in a SIP environment. By converging voice, data, and expanding video/rich media applications, businesses can enhance the end-to-end supply chain, thus measurably improving their effectiveness and efficiency. 8. Unified Communications Applications Collaboration and Unified Communications applications that overcome the challenges of distance are key to today’s businesses. Companies should look for service providers who offer both mobility and unified communications solutions as part of an overall SIP solution. These applications should maintain separation between work and personal identities on smartphones and ensure that employees’ personal phone numbers, applications and information remain private. UC applications should enable unlimited free calling between company offices, and bring together business voice, video chat, instant messaging, texting and presence into a consistent, end-to-end unified communications experience. These types of unified communications tools create energy and foster engagement among workers, partners and customers to fuel productivity and success.
  8. 8. Energize Your Unified Communications with SIP XO Communications 8 Cost Benefits of SIP Trunking With these advantages in mind, let’s now take a closer look at SIP trunking and the cost benefits that SIP trunks make possible. SIP Trunks SIP trunks are one of the more remarkable offshoots of the SIP family of capabilities and one of the more important enablers of SIP-dependent applications. SIP trunks are nothing more than virtual circuits configured and delivered over an Internet connection, typically via the private IP backbone of a VoIP-enabled carrier, as shown in Figure 2. Figure 2. SIP trunks enable convergence to one IP connection over a standards-based connection, eliminating the need for TDM-IP gateways. SIP trunks are often used with an IP-PBX as replacements or “evolutionary next stages” from traditional ISDN-PRI or analog circuits. SIP trunks not only make network deployment more flexible, but also make possible the seamless assurance of operational continuity in the event of a network failure. Their popularity, which is growing rapidly, is largely due to a collection of factors, including cost savings and overall reliability. Some of the more relevant cost benefits are as follows.
  9. 9. Energize Your Unified Communications with SIP XO Communications 9 Reduced Network Service Costs Convergence implies that a single connection can serve multiple access requirements. With SIP trunks: • Voice and data applications ride over one IP connection, instead of separate voice and data services. • The connection is highly efficient because unallocated SIP bandwidth is automatically and dynamically made available for other uses and applications as required (see Figure 3). Added voice compression is available from some service providers, such as XO Communications, enabling higher throughput and efficiency as well. • With centralized SIP trunking, companies can provide high-capacity connections between their IP-PBX phone systems in one or more primary locations that serve as demarcation points to the service provider’s core network and the universal Public Switched Telephone System. This reduces the costs associated with managing separate networks, eliminates local telephone lines and equipment at many locations, and eliminates long-distance charges among headquarters and branch offices. [see Appendix A]. Figure 3. Real-time IP dynamic bandwidth allocation gives priority to voice traffic but makes additional data bandwidth capacity available when phone lines are not in use. Centralized SIP trunking reduces the costs associated with managing separate networks, eliminates local telephone lines and equipment at many locations, and eliminates long-distance charges among headquarters and branch offices.
  10. 10. Energize Your Unified Communications with SIP XO Communications 10 Eliminating PRI Trunks and IP Conversion Devices SIP trunks eliminate the need for PRI PBX cards and IP conversion devices on the customer premises, typically referred to as TDM-IP gateways. This device supports the conversion from IP packets to PSTN traffic, which is normally transmitted over an ISDN PRI. In addition to hardware savings, better throughput is also achieved by minimizing a protocol conversion step. Evolutionary Migration Path Companies that are not ready to replace their legacy TDM PBXs but wish to deploy SIP trunks can deploy media gateways at branch offices to convert TDM voice communication into IP voice traffic (and vice versa), instead of installing a brand new IP system. Thus, legacy TDM PBXs placed in multiple sites are being interconnected via IP networks with the help of gateways that transform the PSTN traffic into VoIP packets. Considerations for Implementation Interoperability As IP-PBXs have entered the market, problems of interoperability have arisen with regard to SIP. Almost all of the first-generation IP-PBXs on the market were designed around proprietary IP signaling stacks because universal agreement on a single protocol had not yet been achieved. Ultimately, SIP was chosen as that universal protocol, and PBX manufacturers wrote proprietary interfaces for their legacy TDM interfaces. This created problems for developers looking to write interfaces for VoIP environments built on media server platforms, as well as complications that required system-by-system interoperability testing or, in some cases, the creation of software interfaces to perform a protocol conversion that ensures interoperability beyond very basic connect-and-disconnect capabilities. Security Thanks to new encryption capabilities such as SIP Transport Layer Security (TLS) and Secure Real-Time Transport Protocol (SRTP), security vulnerabilities are no longer a major issue for SIP implementations. Just as most enterprise organizations encrypt the data that transverses their network, they are requesting that VoIP providers encrypt voice and data packets transmitted over their VoIP networks. Encryption provides customers with an added layer of protection to maintain privacy of VoIP communications and helps prevent unauthorized access to voice conversations. Business-grade service providers offer enterprise SIP customers a choice of either or both of the industry signaling standards for encryption: SIP TLS and SRTP. TLS is based on the earlier Secure Sockets Layer (SSL) method of encryption and uses cryptography to provide endpoint authentication and communications privacy over the internet. SRTP defines a profile of RTP, intended to provide encryption, message authentication and integrity, and replay protection to the RTP data.
  11. 11. Energize Your Unified Communications with SIP XO Communications 11 E911 Requirements SIP and Unified Communications extend the mobile nature of VoIP by enabling communications on a range of wireline and wireless devices that are not tethered to a physical location address. Today’s VoIP-enabled, Internet-based phones offer multiple features for convenience of use that allow callers to use phones from virtually any Internet connection. While this technology has many benefits for end users, it has created many challenges for emergency communications call centers that were designed to receive calls from landline phone services associated with a fixed address. So, how does a carrier provide E911 services to remote locations; and what are the legal requirements for providing back up and E911? Interconnected VoIP service providers are required to comply with enhanced 911 rules adopted by the FCC that are designed to integrate nomadic interconnected VoIP services with the existing PSTN emergency 911 system. Careful planning and proper service provisioning help to ensure phone users in all locations have accurately set up E911 capabilities. To provide E911 service to distributed users on a centralized, shared SIP trunk, the caller’s telephone number must be provisioned so that the E911 service is programmed to ring to the caller assigned local emergency dispatch call center, rather than to a center miles away, across the region or across the country. Nomadic, or wireless 911 users require a different solution from a fixed-IP E911 solution because the VoIP service provider normally delivers the service to a stationary location. Providers that offer enterprises a nomadic E911 capability enable employees to move their phones and still get the proper address information transmitted to the Public Safety Answering Point (PSAP), as long as the nomadic VoIP user keeps their information up to date. Updated information must be provided by the user via location update functionality provisioned by the service provider. Conclusion: Making the SIP Decision Like any large-scale technology shift, the move to SIP should be undertaken only after considering all options and determining that a SIP migration strategy is the right move for the enterprise. In most cases it will be, but it makes sense to ask the questions. Furthermore, it is critical to seek the advice of SIP-seasoned professionals before undertaking the migration. SIP is a fundamentally important technology that will play an increasingly important role in networking, SIP, like VoIP, is a when rather than an if question in today’s enterprise. Its time has come, and businesses of all sizes will be well served if they consider it as part of their evolving network collaboration and unified communications strategy. The XO Advantage Explore your SIP trunking options and savings potential. SIP solutions from XO provide direct access to XO’s private, award-winning nationwide network to bring your employees and offices together with the right connectivity, powered by unified communications and collaborations technology.
  12. 12. Energize Your Unified Communications with SIP XO Communications 12 Market research firm, Infonetics Research, ranked XO as a leading business VoIP provider in North America in 2013, recognizing XO as one of the top two IP connectivity suppliers of business VoIP services1 . XO Communications provides business VoIP services to more than 1.5 million VoIP end users and 35,000 businesses and large enterprises. The company’s suite of communications and collaboration services include award-winning business VoIP, SIP Trunking and Hosted PBX services as well as its XO WorkTime unified communications applications. With the cloud-based mobility and Unified Communications application called WorkTime, businesses can securely integrate and extend the company’s XO VoIP, SIP trunking or Hosted PBX services to the employees’ personal smartphones and computers. This allows IT and network managers with the flexibility to implement mobility with a Bring Your Own Device (BYOD) strategy while reducing costs and eliminating any need to provide and manage company- issued mobile phones. WorkTime empowers employees to innovate, collaborate, and be more productive wherever they go, regardless of device. Workers can select their preferred method of communication from a range of options like IM, text and more—present a consistent work number and presence to others, and use the company calling plan. About Steve Shepard Dr. Steven Shepard, Ph.D. is president of the Shepard Communications Group. A professional writer, educator and industry analyst with more than 25 years of experience in the technology industry, Dr. Shepard specializes in international telecommunications issues, the social implications of technological incursion and the analysis of financial issues related to technology- dependent businesses. He is the author of 45 books on a wide variety of topics and regularly speaks to audiences throughout the world, and has clients in more than 50 countries. Dr. Shepard can be reached at: 1 Source: Infonetics Research, North America Business VoIP Service Leadership Scorecard, May 7, 2013.
  13. 13. Energize Your Unified Communications with SIP XO Communications 13 Appendix Appendix A: Before Enterprise SIP + + + DIA #1 ILEC #1 PRI DIA #2 ILEC #2 PRI Headquarters Regional Office Branch 1 + ++ + Provider 1 Provider 3 Provider 5 Provider 6 Provider 8 Provider 4 + Provider 2 Provider 7 + + Branch 8 Branch 7 Branch 6 Branch 5 Branch 2 Branch 3 Branch 4 BEFORE: Enterprises had to work with more than one local carrier to provide separate Primary Rate Interface (PRI) lines or IP connections to each location. After Enterprise SIP MPLS IP-VPN Network Headquarters Regional Office Failover Branch 1 Branch 2 Branch 3 Branch 4 Branch 5 Branch 6Branch 8 Branch 7 XO Communications AFTER: XO Enterprise SIP provides high capacity SIP trunking to one or more primary locations, and uses your existing phone systems (such as IP-PBXs) and MPLS network to deliver VoIP across all locations. This streamlines management, reduce costs by eliminating lines, equipment and many long-distance charges, provides business continuity, and dynamically shares voice calling capacity across the company.
  14. 14. © Copyright 2014. XO Communications, LLC. All rights reserved. XO, the XO design logo, and all related marks are trademarks of XO Communications, LLC. Energize-Your-Unified-Communications-with-SIP | O140314 10:10:48 About XO Communications: XO Communications is a leading nationwide provider of advanced IP communications, intelligent networking, and network-enabled cloud solutions for business, large enterprise and wholesale customers. These customers include more than half of the Fortune 500, in addition to leading cable, mobile wireless and domestic and international telecommunications companies. XO offers a superior customer experience through its innovative solutions, its employees’ focus on customers and the proven performance of its advanced network. To learn more about XO Communications, visit or For XO updates, follow us on: Twitter | Facebook | Linkedin | SlideShare | YouTube | Flickr