We have two core switch with 10gig ports , at the edge level i need 40gig speed , how do you plan the network?

Trunk port aggregation is Configuring EtherChannel in Switches will give youGB Data Link.

 

Is it possible withG ports to attainGbps.I dont think so.for ptp, fiber optics will give Gbps.refer http://searchnetworking.techtarget.com/feature/-Gigabit-Ethernet-The-migration-begins

7 edge and two core switches. every thing is1 gig ,we have some lags, but an auditor told us to do an upgrade to gig and gig.Now i would sound very stupid.asking him that did he mean the interfaces or the entire switch.

GB capable ports for your uplinks on these switches. So not every port would need this capacity, just the uplinks. For your single chassis switches this means getting a new box, for ones that have linecards you may just be able to get new blades, but it could be hampered by the chassis' backplane capabilities.

Not really sure what you've got running device-wise though.

It doesn't sound like you have a huge environment though, so those speeds seem a bit overkill (particularly G between cores). What kind of workload is the network actually serving?