This article has been updated with comment from Juniper Networks.

Cisco has launched an offensive against Juniper Networks, claiming its smaller competitor missed target dates for several key products.

"Vision doesn't mean much if your track record of execution is murky," Cisco operations executive Robert Lloyd said in a post on the company's official blog, referring to Juniper. "No amount of future promises can make up for failures in execution. Over-promising and under delivering does not result in a strong reputation with customers."

The charges, which Juniper denies, come as Cisco is trying to fend off rival vendors for the routers and switches its makes for the telecommunications market.

Cisco claims Juniper has failed to deliver its 100 Gigabit Ethernet on MX-series edge routers two-and-a-half years after they were first announced. Cisco also says Juniper's T4000 core router - slated for last year - has yet to become available. Juniper has yet to publicly debut its Project Falcom platform despite three launches of the solution and its QFabric data center system is still unavailable, Cisco alleges.

Juniper could not immediately respond to Cisco's specific allegations, but a company spokeswoman cited a statement provided to The Wall Street Journal by Juniper executive Stefan Dyckerhoff, who oversees the company's platform systems division.

"I can honestly say we have met every date we have ever put out there," Dyckerhoff told the publication.

In a later statement, Juniper spokesman David Shane again declined to comment on what he called "a competitor’s publicity stunt."

“Customers tell us they want an alternative to the legacy approach, and we’re focused on delivering innovation for them," Shane said. "It appears as if Cisco has once again lost focus."

Cisco followed up its charges against Juniper with the debut of three new routers designed to help mobile operators cope with rising data traffic, the ASR 901 cell site routers, the ASR 903 unified Ethernet access router and the ASR 9001 small edge router.

Cisco has sheared off non-core divisions like its Flip video camera unit to refocus on its core network gear business and maintain its market share. The company is also trying to bounce back from disappointing quarterly results with a restructuring that will slash $1 billion from its 2012 expenses and eliminate 6,500 jobs, among other cuts.