The argument goes that as networking becomes standards-based, it does not matter about relying on a single supplier. Furthermore, using best-of-breed systems from several suppliers is a waste of time.
This majority view is reflected in the fact that Cisco has firmly established itself as the leading networking supplier in the world, and many users look to the company to provide certified network training courses for their staff.
But analysts are starting to question whether the single-supplier model is cost effective and flexible enough to cope with the demands of the business. Gartner says users could save 20% on their overall network costs by choosing a best-of-breed network infrastructure.
Other analysts question whether it is wise to opt for a Cisco-only infrastructure given the rising number of attacks on its Internetworking Operating System.
Fred Cohen, an analyst at IT research firm Burton Group, said, "While Cisco provides many features and is moving towards standardisation of security capabilities, the management of complex Cisco networks for secure operations is increasingly untenable for even the best-run enterprises. Cisco's products feature high-maintenance security and lack the centralised control and comprehensiveness required by large-scale enterprises."
So what factors should be considered when looking at best-of-breed products as an alternative to the Cisco-based network? The checklist should include: network security, skills, network management and cost impact including contract negotiations.
Mark Slater, technical manager at Extreme Networks UK, said, "If an organisation opts for a single supplier approach, and that supplier has exposure to a certain type of virus, then that organisation's whole network is at risk.
"The potential financial and technical impact on that organisation is considerable. Using a dual-supplier approach allows a company to limit its risk and reduce the percentage of exposure to different suppliers' equipment. This means a company can get half the network running again quickly."
The question of skills and training is, of course, important in deciding what products your staff can cope with. A number of competitors to Cisco are starting to appreciate this and are trying to make their products more compatible with Cisco's.
Analyst company The Tolly Group offers studies showing how rival products work with Cisco technology. Suppliers are using these reports to get into organisations that currently rely on the market leader.
Tony Haigh, principal consultant at telecoms and IT consultancy Mason Group, said, "The main issues revolve around network management and the command line interfaces (CLIs) where there are a number of supplier-specific solutions that are very proprietary in nature - not good when trying to build a multi-supplier network."
Kevin Barnes, business development director at Cisco rival Adtran, said, "Network managers appear more familiar with Cisco technology. However, there are several steps which organisations can take to help to reduce the importance of this factor.
"Suppliers provide free and convenient training and offer incentives to customers to attend these courses. It may also be possible for suppliers to imitate the format and functions, to a certain degree, of the CLI of Cisco products making them easy to get to grips with, without infringing copyright."
The importance of providing a CLI in their own products that Cisco users are familiar with is even cited by main rivals, such as 3Com and Foundry Networks.
Network staff can now use third-party network management software systems, such as the range provided by Intelliden, to control a variety of best-of-breed products, reducing the number of supplier-specific courses that have to be attended.
There are drawbacks to managing a best-of-breed network. Stephen North, director of network tools supplier SwitchIP, said, "It is relatively easy to use two or more network suppliers, as most products can be integrated at a basic level if they use open standards.
"However, problems occur when trying to access more advanced networking features - such as auto back-up and ISDN signalling over IP - which might not operate in a multi-supplier network environment," he said.
So do you need a third-party provider to deliver a mixed network? "Definitely, users still need to feel that they are buying an end-to-end solution, rather than an array of disparate networking products," he said.
"Systems integrators can do the mixing and the matching and deal with any interoperability issues for the user. This means the company gets its best-of-breed network, saves itself a large amount of money and does not compromise on the quality of its communications."
Ian Smith, chief executive of integrator Matrix, said users tend to rely on return on investment analysis and do not pay enough attention to performance and flexibility. "Of course, sometimes you are really lucky and you will get the buy-in of a chief information officer who wants to be different and leave their mark."
But Cisco is not standing still through this onslaught to its market dominance. The company is planning to introduce modular operating systems for its routers and switches to address the increase in attacks on Cisco-based infrastructure.
The move will mean less code is carried by the hardware, which may also help to protect Cisco users from common security attacks that take advantage of loopholes in bulky and sometimes buggy code.
The advantage of modularity, according to Mike Volpi, senior vice-president in Cisco's routing technology group, is partitioning. This should lead to greater reliability as bug-fixes and upgrades involve less downtime.
Clearly running an infrastructure based on one supplier will be simpler than where boxes from several suppliers are used. But if users are prepared to learn new network management consoles and are willing to work with suppliers to integrate their network infrastructure, a multi-supplier strategy can improve flexibility.
Access to feature-rich and higher performance technologies
Competition means favourable pricing - you don't get locked in with one expensive supplier which has proprietary technology
Adopting a best-of-breed, multi-supplier environment means complete flexibility in how users design a network - organisations can avoid being pushed down one route by one supplier's products
Better negotiation power for pricing, faster responses for changes and better overall service
The ability to future proof a network - standard-based products allow them to adopt enhancements in the future
More knowledge required to manage multiple products from various suppliers, but an integrator can solve this
More active management of suppliers and integration issues.