EvoArch suggests an additional reason that IPv4 has been so sta-ble over the last three decades. Recall that a large birth rate atthe layer above the waist can cause a lethal drop in the normalizedvalue of the kernel, if the latter is not chosen as substrate by thenew nodes. In the current Internet architecture, the waist is the net-work layer but the next higher layer (transport) is also very narrowand stable. So, the transport layer acts as an evolutionary shield forIPv4 because any new protocols at the transport layer are unlikelyto survive the competition with TCP and UDP. On the other hand,a large number of births at the layer above TCP or UDP (applica-tion protocols or specific applications) is unlikely to significantlyaffect the value of those two transport protocols because they al-ready have many products. In summary, the stability of the twotransport protocols adds to the stability of IPv4, by eliminating anypotential new transport protocols that could select a new networklayer protocol instead of IPv4.

When creating VPCs and VSwitches, you have to specify the private IP address range for the VPC in the form of a Classless Inter-Domain Routing (CIDR) block. Private IP address range of VPC Use 192.168.0.0/16, 172.16.0.0/12, and 10.0.0.0/8 or their subsets as the private IP address range for your VPC. Note the following when planning the private IP address range of VPC: If you have only one VPC and it does not have to communicate with a local data center, you are free to use any of the preceding IP address ranges or their subnets. If you have multiple VPCs, or you want to build a hybrid cloud composed of one or more VPCs and local data centers, we recommend that you use a subset of these standard IP address ranges as the IP address range for your VPC and make sure that the netmask is no larger than /16. You also need to consider whether the classic network is used when selecting a VPC CIDR block. If you plan to connect ECS instances in a classic network with a VPC, we recommend that you do not use the IP address range 10.0.0.0/8, which is also used by the classic network.