Hi @anil kumar ,
An Azure virtual network is a logical representation of your network in the cloud environment. Your answer to the question is right, the resources such as public IP and Gateway have their own high availability options that you can opt for.
However to talk about disaster recovery and ensuring availability of virtual networks i believe the following document will be of help: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-disaster-recovery-guidance
Please feel free to reach out in case of any questions. Hope this helps.
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