Once they were nowhere, but every vendor spoke of them as the network hardware of the future. Now they are everywhere, and most vendors will tell you they are on the way out.
It seems the all-powerful router is to be banished to the edges of networks, or perhaps will merely fulfil a role in niche markets, as the forward momentum of switching technology builds.
But don't believe for a minute that the router is dead.
Even the likes of IBM - a leading advocate of switch-based networks - agrees the router still has an important, if somewhat less visible, part to play.
"We're seeing a shift in what users are doing with routers," says Paul Kangro, IBM Australia's marketing manager for networking hardware. "There's a shift in what they want to do with the network and that includes voice and video - the lower latency for switches is seeing them replace routers."
Typically, routing is more demanding of processing power than switching, resulting in the latency problem often attributed to routers. High latency creates problems when moving network traffic that is dependent on every bit of data arriving in rapid succession in the correct order. While this is not an issue for file transfers, it does become a problem for applications such as voice and video.
"There is still a place for routers in the network," Kangro said. "But we see the integration of switching and routing through taking the router out of the data path."
The model that IBM and other vendors, such as 3Com, envisage, sees the data path being established by the router, with switches then used for handling data flow. "It will see you end up with a core of switches rather than routers," said Kangro.
While the days of the router as a core device may be numbered, Kangro says this hasn't harmed sales. "We're selling all our model 2210 routers we can get our hands on."
The 2210 allows users to customise their networks for a mix of SNA and TCP/IP traffic through setting priorities. IBM estimates there are more than 50,000 mainframe-based corporate networks worldwide and more than 400,000 networks with its AS/400.
While the high latency associated with routers may be pushing them out of the core of the network, other applications are serving to cement them in their new position. One of these is security.
Securicor 3net is a division of the giant UK-based Securicor, an organisation which started as a specialist armoured car service for banks and major retailers.
(Apparently it is difficult to walk past any shopping centre in the UK without seeing a Securicor van parked outside.)"Cash transfer through networks was a natural progression from physical cash delivery," says Paul McCarney, marketing manager for Securicor 3net in Australia.
The group's diversification has seen it enter into several areas of technology. Not the least of these is its secure transaction business.
Here the router comes into its own. "Latency times of several seconds make no difference in a network that is being used for commercial transactions," says McCarney. Even so, Securicor's iQ routers are still able to reduce latency by carrying out encryption functions on a separate processor within the router.
McCarney says Securicor looks at providing an end-to-end network solution where security is an issue. "We have no restrictions on the bit length we can use for encryption nor on the hardware we can use," said McCarney, in reference to US government restrictions placed on the export of encryption keys.