Hi Anil,
The ideal approach would be to deploy ipv6 along with ipv4 (dual stack). Depending on the features you need and the level of IOS you currently run in your network, it might be fairly easy to deploy ipv6 in dual stach mode.
Regards
Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
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