OSPF implimentation

Do we need OSPF if using more than 50 vlan?
I've experience maintaining network that have about 3000 user and their using about 30 switches..every switch have ospf configuration.. do wee need ospf in internal network and to connect between switch to switch?i'm confuse ...

OSPF would be fine in a environment with 50 vlans, but you could use another routing protocol like EIGRP as well. Switch to switch connections do not need OSPF running, just as long as there is a vlan encapsulation between them, e.g. 802.1q or ISL. Now, in order to route between your vlans you'll need a router/layer 3 switch of some sorts preferrably running OSPF or EIGRP.

what is the effect if we using OSPF between switch to switch?Can it effect the performance of the network?

I'm not sure exactly what you mean, maybe you can provide a little more specific information on how your network is set-up. OSPF is a pretty fast converging routing protocol, but how fast it converges is dependent on how it's designed. I'm not sure what exactly you are meaning by you have OSPF between switch to switch, could you clarify this? This information would help us.

ok..basically the switch is layer 3 switches..
so it have ospf function..network admin design the internal network to connect each other using ospf protocol...below are the example of the network design..

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##

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Legend:
### = core switch
## = distribution switch
# = access switch

*all the switch is layer 3 switches

1)This is internal network and only have about 3000user
2)Do you think this design is ok or need to redesign?

This design seems fine without any more details on it. Cisco has a very good OSPF design guide on it's website, I'd recommend reading it. Redesigning the routing of your network would be a pretty large and possibly complicated project that would probably be best left alone if working correctly.