Corporate networks converge on packet switching

Story contributed by ITAsia.

SINGAPORE, April 2000 - Will the world soon be connected in one homogenous network? Perhaps. But in the mean time, there are a few problems to solve. Ross Milburn, ITAsia's Hong Kong correspondent, asks three major network vendors to provide some clues as to the direction that corporate networks are taking right now.

THE services provided by carriers and ISPs are today more sophisticated, yet cheaper, when compared to services offered in the past. Corporate networks are growing in numbers and complexity, especially with the increasing need for voice, data and video to be carried on a single network. LANs are now universal, and a multitude of WANs circle the globe. One of the prominent trends is toward voice/data convergence and packet switching.

The incentive for corporations to move toward deploying a unified network is not only to improve network performance and simplify management. In a recent study completed by Renaissance World Wide, which examined a number of different business models and total cost of ownership issues, it was concluded that a singular, unified network yields a minimum return on investment of 161% over three years.

Why should an enterprise customer want to go with packet access? The answer is DBA (Dynamic Bandwidth Allocation), says Jean-Francois Pigeon, Newbridge Networks' Regional Marketing Manager for voice & broadband wireless technologies. "DBA allows the enterprise customer to maximise bandwidth usage. For example, bandwidth that is typically allocated for voice traffic during the day can be used for file transfers at night, instead of remaining unused."

Another key consideration in building a packet-access network is the ability to assign end-to-end QoS (Quality of Service) parameters in order to be able to accommodate different traffic types. For this reason, Newbridge believes enterprise customers are best served through the use of Frame Relay as their access fabric for the delivery of both voice and data services.

Convergence of services
According to Newbridge, convergence of voice and data changes the way a company addresses corporate networking needs, Mr. Pigeon says. "Voice services were previously managed separately from data services and those organisations did not need to have much interaction with one another. Enterprise customers found this model to be inefficient in delivering a total networking solution to their users. We responded to this market requirement by providing the ability to deliver integrated services for enterprise customers," he says.

LAN/WAN integration is important, according to Todd Abbott, Vice-President of Cisco Systems Asia. "As network traffic spills over from multimegabit-speed LANs to slower wide-area links, new Internet-class tools are required to help network managers maximise the availability of applications through sophisticated bandwidth management techniques," Mr. Abbott says.

Cisco's response to the intensive use of IP in more complex corporate networks is called AVVID (Architecture for Voice, Video and Integrated Data), a standards-based flexible architecture that enables corporations to cost effectively integrate their networks with the Internet-based business environment.

AVVID comprises four distinct building blocks:

(1) IP infrastructure systems such as multi-layer intelligent switches, routers and gateways with vital network services such as QoS, security and management

(2) Call-processing platforms and solutions

(3) New applications such as unified messaging, new collaborative capabilities and IP contact centres

(4) Intelligent IP-enabled clients, including IP telephones and software-based phones and video clients

Corporations looking to build IP networks can now use a combination of these four elements, and trials are already underway in Asia, Mr. Abbott says. For example, Taiwan's Acer Group is consolidating its existing LAN, WAN and voice networks in its 80 offices around the globe and migrating to an integrated voice, video and data network. Malaysia's leading hypermarket retail chain, Giant TMC, has installed a Cisco VoIP (Voice-over-IP) network that is claimed to be able to cut telephone costs by more than 30%.

In Australia, a co-operative of 12 hospitals within the South West Alliance of Rural Hospitals (SWARH) in Victoria is building a microwave WAN with fully switched, Cisco-based VoIP technology. This replaces a PABX and provides tariff-free calls among 33 sites on an integrated voice and data network.

Also targeted at large companies, Nortel Networks' Meridian PBX is being IP-enabled to provide packet-switching capability instead of only voice-switching functions. IP telephony is possible, and so are 'software phones' - multimedia PCs equipped with software to emulate a digital phone.

"Using a laptop with this software, and a handset, the user can plug into an Ethernet LAN connection anywhere on a corporate network to obtain not only a data connection, but a telephone service with portable numbering. So there is no need to reconfigure the network, or inform people of a different extension number," says Syd Wong, Nortel Networks' Business Development Manager for enterprise solutions.

Another application for Nortel's Meridian is the convergence of voice onto a LAN backbone. "If you have a LAN in Hong Kong Island, and one in Kowloon, they are connected by a backbone," Mr. Wong says. "Your two PBXs are usually connected by a tie-line from the phone company. With Meridian, the IP router will send the voice traffic over the LAN backbone, so you can get rid of the dedicated voice line and save money."

Frame Relay can now handle voice and data routinely. Says Newbridge's Mr. Pigeon: "Corporations can go to the telephone company and get a trunk line and Frame Relay for their data traffic. But as a small player, you do not get good rates, you wait six to eight weeks for service connection, and should you get downtime, you wait for service.

"Now, with convergence, you can use equipment such as the Newbridge 3608 Frame Relay access device for delivery of voice and data services. The equipment meets the relevant standards (G.729 and the ITU standard) for 'near toll voice quality', expressed as a MOS (Mean Opinion Score) of 3.92 out of 5 [compared with 4.10 for standard telephone service]," Mr. Pigeon explains.

ATM vs. Ethernet
One issue facing managers of corporate networks relates to the advantages of ATM and high-bandwidth Ethernet. "ATM is able to provide an extremely high QoS for integrated video, voice and data, but the higher complexity and deployment cost of an ATM backbone may be much more than 100Mbps Ethernet, or even Gigabit Ethernet" Nortel's Mr. Wong says.

The choice of protocol depends upon the application, according to him. "If your company is running a lot of multimedia and need to run it over a fairly large campus, then maybe ATM is the better choice. But if you are talking about applications that don't need a lot multimedia [capacity], Gigabit Ethernet may not be a bad choice.

"We are definitely moving towards the convergence of voice and data; voice products will be IP-enabled, and routers and other data products will be voice-enabled. Most products will be voice/data hybrids in future. For example, our voice switches, Norstar and Mercator products, already have IP connectivity today," Mr. Wong adds.

The convergence of voice, data and video onto IP can serve small companies very well because these firms tend to have less complex IT infrastructures and fewer legacy systems and applications, according to Cisco. Integrating IP into these environments can be relatively quick and inexpensive -- far quicker and less costly than what it would take for a large enterprise, which might have to re-engineer a network catering to hundreds or thousands of users.

The cost-benefit analysis of moving to an integrated IP infrastructure can be more evident in smaller companies, too. Benefits include an immediate reduction in IDD charges and a return on investment that can easily be measured to justify the capital investment.

Voice-enabled Web sites

Convergence also manifests itself at a Web site that is voice enabled. A small company's telephone system can be linked with its Web site by using a Nortel product called Enterprise Edge, which is a small PBX that incorporates data routing. Enterprise Edge can connect a LAN to an ISP and voice-enable the Web site. Customers can click on a 'voice button' on a Web page in order to talk to someone at the company, or to trigger a voice response.
"A lot of online consumer business is made up of impulse sales, and if you cannot make the sale quickly, you lose the business forever. So by having voice response on the Web site to respond to queries, instead of just presenting static information, the success rate [of closing an online sale] will be much higher," Mr. Wong says.

Enterprise Edge also provides regular voice services such as voice mail, and if this system is available at two locations over a corporate WAN or leased line (even in different countries), VoIP is possible.

The fundamental issue that arises when talking about integrated voice, video and data packet networks is QoS, just as it is the stumbling block that carriers encounter in deploying IP on a wider scale. Cisco has introduced an architecture sensitive to QoS issues based on Version 11.1 of its IOS (Internet Operating System) software for routers.

IOS uses a packet classification and bandwidth management application that uses CAR (Committed Access Rate). In Cisco's scheme, the three precedence bits that make up the TOS field in the IP protocol definition for the IP header are used to define the class of service for that packet.

Congestion management at the router level is handled by RED (Random Early Detection) and WRED (Weighted Random Early Detection). Rather than waiting for the router's buffer to fill and then discarding packets indiscriminately, RED and WRED monitor the buffer depth and start discarding selected packets early, reducing the chance that large numbers of packets will be dropped later due to a full buffer.

Bandwidth allocation employs WFQ (Weighted Fair Queuing), and a fourth aspect is the distribution of destination-based packet classification policies throughout large intranets via the BGP (Border Gateway Protocol).

Voice-over-IP
Newbridge's Mr. Pigeon has reservations about over-reliance on the Internet. "IP can be a cheaper solution, but it does not provide the quality of service that we are used to with the telephone network," he says, asking pointedly: "How often do you have to reboot your phone today?
"On an IP backbone, you can have voice, video, and e-mails, time-sensitive to a different degree. But the routers cannot differentiate the traffic yet. Standards are being developed to address this, but they are not there yet," he adds.

Can problems of latency caused by congestion be solved by providing enough capacity to avoid the congestion? "To throw bandwidth at it is a reasonable proposition on a local campus but on international links, where bandwidth is expensive, it is not an option. Newbridge believes service providers will need a fabric to preserve QoS, such as ATM or Frame Relay, to address this requirement," Mr. Pigeon says.

Providing access devices is another problem associated with VoIP deployment. "In an enterprise network, access is available but the IP terminals, H.323 headsets, are much more expensive than the US$10 phones you can otherwise buy for analogue services. I do believe, however, that there will be ubiquitous IP access in two to three years," he adds.

Future of ATM
Says Jami WHAT'S HIS LAST NAME?, Newbridge Networks' Regional Marketing Manager for data solutions: "One of our competitors is selling an IP solution for corporate networking on the basis that you will be able to leverage IP infrastructure when QoS standards become available. The problem is, when you have to upgrade these IP services with QoS, you will have to throw away your existing routers and infrastructure.

"The ATM vs. IP debate rages on, but in reality, if you go to IP service providers, they use ATM at the core."

In some networks, ATM and Frame Relay were alternative options. "In enterprise networks, you are more likely to see Frame Relay for access. Below 2Mbps, Frame Relay is cheaper; above that bandwidth, ATM is cheaper," Mr. Jami adds.