With large corporate networks coming under pressure to handle even more bandwidth-hungry communications, Nortel Networks has positioned itself to provide the technology required to overcome this. The range of solutions available covers the needs of corporate users in local or metropolitan area networks (LANs and MANs) as well as the infrastructure for service providers and carriers supplying connectivity for such customers.
Nortel Networks Optical Ethernet technology answers the carriers` need for a cost-effective means of delivering flexible bandwidth. In providing a proven, end-to-end Ethernet link over fibre optic connections, it eliminates problems common in other carrier systems.
Sirshem Moodley, Chief Technology Officer at Nortel Networks South Africa, points out the advantages.
"Optical Ethernet removes bottlenecks with its massive bandwidth abilities of 10Gbps," he says. "More importantly, it also removes a number of problems found in frame relay (FR) and asynchronous transfer mode (ATM) solutions.
"Firstly, Optical Ethernet has none of the addressing complexity of other systems. Secondly, it eliminates multiple protocol conversions - as it runs Ethernet throughout from the campus, across the MAN/WAN - greatly reducing latency and jitter, which cause problematic delays in data transmission.
"Lastly, it is flexible and easily upgraded after installation. Optical Ethernet bandwidth can be upgraded in steps as small as 1Mbps, without the need for replacing or reconfiguring the previous equipment.
"This, in itself is a significant cost saving for the operator. Independent studies have also shown that an Optical Ethernet solution costs only a quarter of the price of comparable ATM or SDH (synchronous digital hierarchy network) technology."
For corporate customers, research from most of the major international research groups points to the steady increase in data traffic resulting from businesses being online on a nearly continuous basis, often employing sophisticated voice and video multimedia applications alongside the established data transfer solutions.
The difference, as Moodley points out, is the need for greater reliability to cope with new demands on the network infrastructure.
"Previous standards such as Gigabit Ethernet and the spanning tree protocol (STP) are rapidly becoming inadequate to deal with the volumes of traffic on larger campus networks and metropolitan area networks (MANs). Network reliability also depends on detecting links that cause loops. STP was able to do this, but only by blocking the network port concerned.
"Unfortunately, the time needed to resolve such problems using STP increases directly with the size of the network, causing delays that could stretch to minutes. Multimedia-enabled networks cannot afford such delays.
"Nortel Networks offers the Passport 8600 solution which introduces two new technologies to circumvent such problems for MANs based on fibre-optic backbones. Split Multi-Link Trunking (SMLT) enables smart connections between the edge switching equipment that connects to end users and the core/aggregation switches that handle traffic on the backbone.
"SMLT allows recovery from full or partial network failures in less than one-second time frames, essential for the quality of service needed for voice and video applications. It also enables load sharing which can provide 99.999% reliability."
The other need which Nortel Networks systems address is to maximise the data capacity without an unacceptable increase in cost of installation.
"On any optical network that goes beyond the single-mode fibre Gigabit Ethernet technology, there are two main alternatives," says Moodley.
"These are dense or coarse wave division multiplexing (DWDM or CWDM).
"DWDM depends on very accurate lasers with expensive cooling systems, whereas CWDM can use less expensive equipment which still enables eight logical connections on each strand of fibre. This creates the capacity for eight gigabits on fibres that would normally only handle one gigabit. Multiple devices can be connected via the same network resources in either a point-to-point or ring topology.
"The immediate benefits of Passport 8600 technology include increased capacity and reliability. It also offers greater cost savings compared to DWDM and has the scalability to handle future growth of the network. Apart from an eight-fold improvement in capacity, it also outperforms Gigabit Ethernet in allowing greater transmission distances - an important factor as the demand for larger campus networks continues in the local market.
"Nortel Networks is well placed to offer such advanced technology to local corporate users, based on its extensive experience with major installations for overseas customers."
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Nortel Networks is an industry leader and innovator focused on transforming how the world communicates and exchanges information. The company is supplying its service provider and enterprise customers with communications technology and infrastructure to enable value-added IP data, voice and multimedia services spanning metro and enterprise networks, wireless networks and optical long haul networks. As a global company, Nortel Networks does business in more than 150 countries. More information about Nortel Networks can be found on the Web at http://www.nortelnetworks.com.
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