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June 2000

Brough Turner IP QoS? Yes. IP 
Quality Of Service -- Present And Future


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QoS On The 'Net?

Implementing quality of service (QoS) in an IP network is a hot topic these days. Today IP (Internet protocol) is ubiquitous -- the only protocol to consider for new applications -- but it's a best-efforts protocol. IP works great as long as there is enough bandwidth, but as soon as there is any congestion, everything slows down equally. This limits IP's ability to replace the telephone network, or even the majority of SNA (Systems Network Architecture) data networks. Obviously delays have a major impact on VoIP traffic. But, if you've just spent millions of dollars on computer telephony gear to shave seconds off of call center answering times, can you afford to add back seconds of delay while the agent waits for a screen refresh? Giving priority to mission-critical applications in the presence of network congestion is an equally important motivation for a focus on QoS for IP.

In most cases, however, LAN bandwidth is fairly inexpensive, so there is limited incentive to deploy QoS technology there -- especially if there is appreciable first cost or maintenance cost associated with QoS. It's usually easier to add more capacity -- higher speed segments or additional Ethernet switches. A similar effect is occurring in the WAN. In recent years, a vast amount of new fiber has been laid and long-distance bandwidth, at least for service providers, is getting surprisingly inexpensive. As a result, major data service providers offer frame relay circuits with packet delivery guarantees and prices that are independent of distance, at least within the United States. Other carriers are offering IP services with latency and packet loss guarantees. But these carriers are providing their guarantees using ATM equipment or plain IP over-provisioning -- they are not deploying IP QoS, at least not yet.

So where is the big need for QoS technology? The biggest source of IP congestion occurs at the edge of the enterprise, where an enterprise's 100 Mbps or Gigabit Ethernet LAN backbone connects to the WAN access link -- a connection that may be, at best, a single 1.5 Mbps T1 pipe. It's the access network that is the bottleneck today, and for the foreseeable future. This is the first place where IP QoS technology will pay off, by giving critical applications, such as voice, priority access to the limited bandwidth pipe to ensure they have low delay and low packet loss.

Several standards are complete or nearly complete, and diverse products are beginning to roll out, creating a flurry of press releases and lots of hype. But what IP QoS technologies are actually available? The first IETF (Internet Engineering Task Force) effort to be completed is a scheme called IntServ (Integrated Services). IntServ introduced the Resource Reservation Protocol (RSVP) together with a structure for making specific reservations of bandwidth at every router along an IP path. Unfortunately, in order to reserve bandwidth, some information must be stored in every router along the path and this must be done for every session. There are also negotiations required at every router along the path. If there are millions of users and billions of paths, as in the public Internet, IntServ quickly becomes cumbersome. It doesn't scale well.

To address this scalability issue, another IETF working group developed DiffServ (Differential Services). This standard is nearly complete and trial deployments are beginning. Under DiffServ, an individual user's requests for bandwidth are aggregated into a few classes of service which are provided from router to router on a per-hop basis. Traffic is metered and shaped at the edge of a DiffServ network to conform to predetermined service level agreements, so the core network is not overloaded. Each traffic class is designated to receive a particular kind of treatment, and statistically it is very likely to get this treatment. Because there is only general information about a few classes of per-hop behavior stored at any one point within an IP network, the DiffServ architecture for IP QoS is expected to scale to any size. The downside is that there is only a statistical guarantee of a specific behavior. The statistics can be made arbitrarily good, but there's never an absolute guarantee.

In an entirely separate effort, the IETF has been working on multi-protocol label switching (MPLS). MPLS provides virtual-circuit-like connections through an IP network -- a major aid for traffic management and therefore useful in support of QoS objectives. Basic IP is a connectionless protocol. This means each packet gets to its destination by whatever is the best route at that moment. In this, IP differs from protocols such as X.25, frame relay, and ATM, which are connection-oriented and establish a path or a virtual circuit between a source and destination. In a connection-oriented network, all packets on one virtual circuit use the identical set of links and switch/routers. With a limited set of virtual circuits, provisioning problems are more tractable. Packets can be sent along an explicit path different from the one constructed by normal IP routing. Alternate virtual circuits can be pre-provisioned to provide rapid cut-over in the event of a link failure. And as long as bandwidth is provisioned for each virtual circuit, the circuit can provide service guarantees. MPLS provides all of these benefits for IP traffic, merely substituting the words label-switched path for virtual circuit.

Today it is possible to map IP flows to ATM virtual circuits and provide IP differentiated services in that fashion. MPLS can leverage existing ATM switches, but can also work on any IP transport, potentially reducing the complexity of maintaining both IP and ATM networks. Like DiffServ, MPLS standards are very new and implementation experience is limited. But these two new technologies are going to dramatically change the communications landscape.

Within the next 12 months, we'll see the first IP differential services offered. Initially these will be offered by mapping IP QoS to underlying ATM services, but within the next 12 to 24 months, both MPLS and DiffServ will be deployed and the cost of providing IP QoS will begin to fall. As the technology progresses, the cost of providing special services for applications such as voice and mission-critical systems will decrease substantially. The statistics of utilizing DiffServ are such that providing high priority or low latency for only 10 to 15 percent of a network's traffic has a negligible impact on the rest of the best-effort traffic, so in time, 10 or 15 percent high-priority packets may be included with basic IP service. And since the total amount of traffic on IP networks is growing at an exponential rate, voice traffic may well be less than 15 percent of corporate traffic.

Today, a majority of corporations run traditional TDM (Time Division Multiplexing) networks for voice traffic and use SNA networks for their mission-critical data applications. But with the emergence of IP QoS services over the next three years, any SNA-based application that requires updating for any reason will be moved to IP as a simplification strategy.

The availability of IP QoS will directly affect our telephony infrastructure as high-quality VoIP will be easily deployed. All PBX vendors today have products or product plans that support IP connections between different corporate sites. They also have IP-PBXs and Ethernet telephones in the pipeline. While it's a nascent market, corporate telephony is poised for major change in the next three years. And, as IP-PBXs emerge, there will be additional opportunities for new applications far beyond what PBX vendors are considering today. At the very least, we will break away from the narrow-band (three KHz) telephony we've lived with for the past 120 years. We may not need full CD-quality for voice telephony, but VoIP will surely sound better than "toll quality" does today.

The combination of high-quality audio and speech recognition will spawn other interesting applications. For example, I'd like a business-oriented chat service that could actually help me in my daily work. When I chose to be "on-line," this virtual workgroup or virtual water cooler application would provide a private, secure, IP-based, open-wire service over which I could converse with co-workers, as if they were in the room with me, even if they were in another country. I would want very high-quality voice activity detection so that there wasn't any background noise, only the voice of someone in my workgroup. And, I'd also like high-grade speech recognition, so that I could speak a name and my voice would be passed to only that person. All the needed technology exists today, at least in the lab. With QoS in the corporate IP backbone, it could be a reality in short order.

Internet telephony has come a long way from the hobbyists of 1995, but the future is more exciting as IP QoS makes VoIP routine and unleashes a host of new applications. Now is the time to figure out the new communications services you want.

Brough Turner is senior vice president of technology at Natural MicroSystems, a leading provider of hardware and software technologies for developers of high-value telecommunications solutions. For more information, visit the company's Web site at www.nmss.com.

Services News

dynamicsoft Intros eConvergence
dynamicsoft has introduced its complete eConvergence Server Solutions. Led by the newly-announced SIP Application Server 1.0, the eConvergence product family marks a ready-to-deploy solution suite based on SIP. dynamicsoft's eConvergence product suite gives communication ASPs the open, scalable tools to quickly develop and deploy enhanced services that combine Internet telephony and other session-based services with the Web, creating a robust experience for their customers. With this suite of solutions, dynamicsoft addresses critical needs for deploying converged networks, linking components such as call control, routing management, subscriber management, and accounting/billing.
No. 530, www.itmag.com/freeinfo

GTE Internetworking Announces ESP Direct
GTE Internetworking announced ESP Direct, a new high-quality, low-cost VoIP service that provides local inbound dial reach covering 80 percent of the U.S. metropolitan population. The service allows "Enhanced Services Providers (ESP)" to deliver communication services such as unified messaging, Internet call waiting, and IP fax to their end users without having to make a large network infrastructure investment.
No. 531, www.itmag.com/freeinfo

Trillium And Vsys Partner
Trillium Digital Systems and Vsys announced an integrated solution to accelerate the deployment of Vsys' Necisa (Network Convergence Integrated Switch Architecture) IP telephony platform. By integrating Trillium's industry-leading H.323 software solution into the Necisa Softswitch platform, Vsys enables network operators to quickly implement carrier-class, end-to-end IP telephony solutions that meet the performance, capacity, and scalability requirements of next-gen networks.
No. 532, www.itmag.com/freeinfo

ADC Intros Next-Gen Broadband Wireless Access System
ADC has announced the worldwide availability of the Axity Broadband Wireless Access System, a carrier-class architecture for two-way delivery of communications services over the MMDS wireless spectrum. The introduction of the Axity system further enhances ADC's focus on the access sector of broadband communications networks, and is an integral part of the company's solutions for DSL, cable, and wireless.
No. 533, www.itmag.com/freeinfo

Phillips Group Predicts Triple Demand For Managed Services
According to a study from The Phillips Group, during the next three years, more than half of U.S. companies will begin converting their data, voice, and video traffic onto a single next-gen network utilizing IP telephony. Eighty-one percent of the sites in these converged networks will be connected using managed services from various service providers, instead of private network, making a reversal of current trends in which private lines are the dominant choice. Only 28 percent of company locations currently utilize managed services for their data network.
No. 534, www.itmag.com/freeinfo

VocalData Releases IP Local Exchange Solution
VocalData announced the release of their complete IP local exchange system, allowing service providers to deliver feature-packed IP voice services and high-speed Internet access all over a single packet-based connection to their customers. The architecture of VocalData's solution functions in carrier or multi-tenant networks to allow service providers and their customers to capitalize on the efficiencies and cost-savings of a single communication network infrastructure. The solution is also scalable, allowing service providers to cost-effectively serve a limited number of customers, but with the flexibility to grow into large network-wide configurations.
No. 535, www.itmag.com/freeinfo

IPeria Announces Service Node Version 1.2
IPeria has announced that version 1.2 of its Service Node and two new communications applications, unified messaging and voice activated voice e-mail, are generally available for deployments and trials by service providers. The scalable, carrier-class IPeria Service Node enables next-gen telcos, CLECs, wireless providers, and ISPs to deliver value-added enhanced services to their customers. These services, in turn, help providers produce revenue, increase average revenue per user, and retain valued customers.
No. 536, www.itmag.com/freeinfo

Belle Systems Launches IMS 3.2
Belle Systems announced the launch of the latest version of its Internet Management System (IMS). IMS 3.2 offers improved scalability, faster data processing, and improved management of VoIP services. It is designed for ISPs, telcos, and corporate organizations deploying VoIP and other IP-based services. The latest version builds on the existing capabilities of IMS, which enables the management of all aspects of IP services from initial provisioning and deployment through to mediation, rating, and billing.
No. 537, www.itmag.com/freeinfo

visitalk.com Offers PC-To-Phone Service
visitalk.com will extend its existing free global PC-to-PC audio and video calling services by enabling its members to place calls from their PCs to telephones worldwide. deltathree.com and MediaRing.com will partner with visitalk.com to provide the PC-to-phone calls, which will be initiated from the visitalk.com Web site. PC-to-phone calls will complement visitalk.com's existing IP telephony services and offer members new options for their long-distance calling.
No. 538, www.itmag.com/freeinfo

Net2Phone To Launch YAP
Net2Phone has introduced a line of hardware solutions designed to enable a wide range of users to easily make Internet phone calls. The new hardware line is called "YAP -- Your Alternative Phone," and will be sold worldwide to consumers and enterprises through retail superstores, resellers, and VARs this year. YAP Business solutions will provide multi-line communications solutions suitable for small businesses and larger PBX corporate environments. YAP Consumer products will allow end users to connect any regular phone into Net2Phone's Internet calling network through a standard phone line or an Internet-enabled PC.
No. 539, www.itmag.com/freeinfo

GRIC, HCI, USAN Deliver IP Services To Africa
GRIC Communications and HCI Technologies announced an agreement with the United States African Network (USAN) to deploy multiple value-added IP services for calling to and from selected countries in Africa. The IP services will enhance and expand Africa's limited bandwidth and improve the quality of intra-Africa calls, as well as overseas calls initiated from select African nations. USAN, a prepaid international long-distance provider, will be in a position to expand its service offerings within the African continent. HCI is now growing its business beyond the United States. GRIC will be extending its global reach into Africa, providing multiple IP-based services to and from five continents.
No. 540, www.itmag.com/freeinfo

PassCall, Jacada To Deliver WAP Solutions
Jacada and PassCall Advanced Technologies will market and deliver solutions that will provide immediate and complete connectivity to any Internet and mainframe applications from any wireless device. Under the agreement, PassCall and Jacada will work together to deliver WAP-based solutions to AS/400 and mainframe customers worldwide. PassCall has developed a technology that provides users of mobile phones and other wireless devices with Internet access, utilizing existing Internet Web sites. PassCall's GateWave technology enables access to any Internet site, in any language, via any cellular device.
No. 541, www.itmag.com/freeinfo

eVoice Partners With Dialpad.com
eVoice has become the exclusive voice mail partner to Dialpad.com, under an agreement that creates a one-stop shop for consumer voice services online. Dialpad.com will offer eVoice's free home voice mail to its subscribers, while Dialpad.com's one-click Web phone calling service will be available to all users of eVoice's service.
No. 542, www.itmag.com/freeinfo

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QoS On The 'Net?


How do you manage not to have a "packet traffic jam" on a road you don't own? You have to be a very smart traffic cop.

Let's take a step back for those who may be new to the Internet telephony game, and discuss the necessities that make good quality. Three things are needed, and if any one of them is missing, you have the makings of poor call quality. First, the technology has to be top-notch and has to have been tested in a serious lab. The gateway and gatekeeper software have to be designed for more than point-to-point calling on a controlled WAN (wide-area network) basis. The computers and operating systems need to be industrial strength. Second, there has to be adequate bandwidth available. And finally, someone has to manage the routing.

Global IP carriers who use the Internet for calls pose the greatest challenge to gateway manufacturers. The Tier 1 global IP carrier can have upwards of 100 points of presence (PoPs) and they are on a fully loaded, truly distributed network that is susceptible to congestion.

The carrier must address all three causes of poor call quality. First it must use equipment from manufacturers that have extensive experience in the industry. It should purchase from vendors who are committed to interoperability. It should not purchase equipment from any manufacturer that is not committed to supplying onsite technical assistance. The manufacturer gets as much out of this type of relationship as it gives. It receives invaluable information addressing the challenges of those few companies that are on the cutting edge of the new global convergence market.

Secondly the carrier needs to test any potential termination sites for adequate Internet bandwidth. There are unfortunately some places in the world where there is simply not yet enough bandwidth to assure quality real-time voice and fax. The carrier building the network should test extensively before deploying gateways to see what the latency is and how much packet loss there is to a certain location. It may be that Internet telephony cannot happen to a location until new satellite connections or new fiber are available.

It is also up to the carrier to deal only with global Tier 1 ISPs that have interconnection relationships with other Tier 1 ISPs. The Internet is no longer owned by governments and universities. It is NOT a not-for-profit organization. It is made up of many for-profit companies that interconnect with each other. I find it hard to describe the Internet; maybe the only thing that makes it the Internet is that I pay -- both at home and ITXC pays at the office -- not by the minutes, but for access. I pay $19.95 at home and the company pays thousands of dollars a month each to several Tier 1 ISPs for huge access pipes. The wonderful thing about the Internet, besides the creativity it has spawned, is that access gets one anywhere instantly.

For a global carrier, it is essential to do business on the Internet. Not simply advertising, but actually providing transport on the Internet. The cost of calling between G7 nations is decreasing at a very fast pace. It is coming down much more slowly between developing countries, but it is still coming down. The Federal Communications Commission and the World Trade Organization are applying pressure to governments to encourage competition and to lower settlement rates. In order to keep margins up, carriers need to manage their costs. The cost of transport is a large part of the carrier's cost structure. Using the Internet dramatically changes costs. Likewise, it dramatically changes quality issues.

The final condition for good quality calling is the management of the routing to eliminate or reduce latency and packet loss.

The Internet is truly a distributed network with no single points of failure. A business following Internet economics also has no single points of failure. In the early adopter Internet telephony industry, let's be honest, there is no such thing as a gateway or router that cannot fail. There is no such thing as a part of the Internet that is not subject to occasional congestion. So the answer lies in redundancy.

The carrier must have multiple gateway operators at each terminating site. Each gateway installation should ideally have its own ISP and central office. The carrier itself should have more than one Tier 1 ISP. The carrier should have redundancy in its own hubs and redundancy in its routers and switches. It should have the ability to provide backup managed IP or PSTN if needed to cover times of extensive Internet congestion. No single element of a global Internet telephony carrier's network is up to the 999s of reliability, but the total of all the elements (put together) is.

In order to manage this redundant network, the carrier absolutely needs a 24x7 network operations center (NOC). The NOC should be using tools to continually test for quality. If the NOC detects that quality (call completion, call duration, Internet congestion, or latency) is not up to strict standards, it needs to have the ability to dynamically reroute calls to improve quality. Unfortunately, there are no tools that can be purchased off the shelf. Today's leading Internet telephony carriers have to write their own tools. In order to write an intelligent tool, intelligence must first be gathered. Tier 1 Internet telephony carriers have developed databases of call durations and completion rates and what the results of ongoing "ping" tests should be to certain locations at certain times of the day. These tools notify the carrier when they are not achieving a prescribed standard of service.

Staff members who see degradation in the network do several things. They notify the terminating company that there is a problem and begin the troubleshooting process. At the same time, they reroute calls to other terminators or through other transport mechanisms until they solve the problem. It is not advisable for carriers to leave this observation and intricate rerouting to affiliates as some clearinghouses do. It takes highly trained and experienced staff to handle this type of issue.

Maintaining QoS today is a skill that is being developed by cutting-edge Internet telephony carriers. It is accomplished by a combination of procedures, policies, sophisticated routing tables, and constant vigilance by trained staff and newly developed software tools. The industry will eventually come to agreement on a set of standards for QoS, but today it is the early entrants into the market who are creating the rules.

Mary Evslin is vice president of marketing and customer services at ITXC Corporation. ITXC is the service providers' service provider and the operator of infrastructure that voice enables the Internet. The company's WWeXchange Service provides phone-to-phone wholesale call completion for carriers and resellers and has been chosen by 10 of the top 12 U.S. facilities-based carriers, leading European competitive carriers, and PTTs worldwide to complete their customers' calls. For more information, visit the company's Web site at www.itxc.com.

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