Cisco with its recent announcement that they are focusing back on their core router business, they would have been crucified by the shareholders if they try to acquire either Nokia or RIM now.

FORBES: Who Would Want Nokia Or RIM In Wake Of Google-Moto?

Juniper Networks and Cisco may have had a field day in the core router market cornering over 80% of the market and enjoying a near-duopoly until now but all that might change soon.

FORBES: Juniper Concerned As Alcatel Lucent Targets Core Router Market

With carriers moving to higher-speed 4G networks like LTE to support the explosion of data traffic caused by the rapid adoption of cloud computing solutions and burgeoning video usage, Alcatel Lucent is looking to take advantage of the industry transition and leverage its existing base of edge routers to find an opening in the core router market.

FORBES: Juniper Concerned As Alcatel Lucent Targets Core Router Market

Although enterprise routers remain the single largest profit driver for Cisco, we note that the service provider router segment (including both edge and core routers) does generate a combined profitability beyond the individual contribution from the enterprise segment.

FORBES: Enterprise Routers Are Cisco's Engine