SAN JOSE, Calif. (

TheStreet

) --

Cisco's

(CSCO) - Get Report

$99 million deal for

CoreOptics

marks another stab at the optical networking market by the Net infrastructure giant.

The move, announced Thursday, will help thrust Cisco into the optical transport market directly in competition with outfits like

Ciena

(CIEN) - Get Report

,

Infinera

(INFN) - Get Report

and

Nokia

(NOK) - Get Report

Siemens

(SI)

. CoreOptics makes optical components and chips that process signals on fiber optic networks.

Microsoft's Courtside Competition (Forbes)

Pushing great loads of data over lightwaves on fiber optic networks instead of electrons over copper wire has helped telcos handle the capacity and speed challenges of rapidly growing Internet traffic.

While huge in the electronic router and switch business of the Net, Cisco has had only limited success in optics. Analysts say the move is more than likely an attempt to defend threats to its core business from rivals like

Juniper

(JNPR) - Get Report

-- as well as gain a foothold in optical transport.

CoreOptics counts

Verizon

(VZ) - Get Report

,

AT&T

(T) - Get Report

and

Deutsche Telekom

( DT) as its customers, says JPMorgan analyst Rod Hall.

Cisco shares were down 1% early Friday to $23.03 in another day of tech selling. As illustrated on the chart above, Cisco shares have fallen 15% in the past month, slightly out-plunging the Nasdaq's 12% decline in the same time period.

--Written by Scott Moritz in New York