AWS Networking
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AWS has a service called as VPC (Virtual Private Cloud) for creating private networks.
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VPC will be at a region level.
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In AWS, we have infrastructure at AZ (Availability Zone), So we create subnets at az level
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Subnet is at AZ level and one AZ can have multiple subnets. Subnet will be linked to only one AZ.(AZ => subnet can be classified as one to many)
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Lets create our first vpc to run an ntier application. This ntier application has
- web servers
- app servers (business logic)
- db servers
- mgmt servers (administration)
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Lets create vpc in oregon region
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Oregon has 4 AZ’s and the region code is us-west-2
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Now AZ’s will be
- us-west-2a
- us-west-2b
- us-west-2c
- us-west-2d
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Lets create the subnets.
- web => us-west-2a
- app => us-west-2b
- db => us-west-2c
- mgmt => us-west-2d
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Each subnet will have 200 devices 2^n ~= 200 n=8.
- VPC CIDR = 192.168.0.0/16
- web = 192.168.0.0/24
- app = 192.168.1.0/24
- db = 192.168.2.0/24
- mgmt = 192.168.3.0/24
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Lets create vpc
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Now lets add subnets
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Create other 3 subnets
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Lets delete this vpc
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Now Lets create one more vpc as described in below image
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Each subnet should be able to connect 200 devices
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Subnet Sizing:
- AWS allows you to create subnet block between the sizes /28 (16 devices) to /16 (65536)
- In Each subnet you will not be able to use 5 ip addresses (x.x.x => subnet cidr)
- x.x.x.0 => Network Address
- x.x.x.1 => Reserved by AWS for VPC Router
- x.x.x.2 => Reserved by AWS for the ip address of DNS Server
- x.x.x.3 => Reserved by AWS for future usage
- x.x.x.255 => broadcast address
- Number of ip’addresses available in subnet is (2^n – 2), in the case of AWS it is (2^n-5)
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Next Steps:
- There is already a vpc in your region (default vpc)
- How to create networks from command line. Refer Here to install aws cli on your system.
