About WIZnetThe WIZnet module is compatible with the official Arduino Ethernet library, which is easy to use and very powerful. However it does not have DHCP built-in which can make setup a bit frustrating if your network isn't friendly.
May i know what doesn't it mean by "network not friendly" ?
I have difficulties to establish stable connection to network with my wifi shield.
The connection keep on reset (Connect and disconnect)
Would it because of the DHCP?
May i know any hints that i can refer to fix this problem?
Since the W5100 doesn't support "hardware" DHCP, you can program it your self though, you must set it with an address that is accepted by your switch or router.
The problem arises if the router doesn't accept it. So far I've yet to find one, but it may happen. Once the IP is set in your shield eerything should work.