Knowledge checks

Network Address Translation box

HTTP cache

IP router

SDN controller

HTTP load balancer

WiFi base station

Ethernet

DNS

WiFi

TCP

HTTP

IP

The end-to-end argument advocates placing functionality at the network edge because some functionality cannot be completely and correctly implemented in the network, and so needs to be placed at the edge in any case, making in-network implementation redundant.

The end-to-end argument allows that some redundant functionality might be placed both in-network and at the network edge in order to enhance performance.

The end-to-end argument advocates placing functionality at the network edge to optimize performance, such as end-end delay.

The Internet protocol stack has a “thin waist” in the middle, like an hourglass.  The Internet Protocol (IP) is the only network-layer protocol in the middle layer of the stack.  Every other layer has multiple protocols at that layer.

... after matching on the source and destination IP address in the datagram header, the action taken is to forward the datagram to the output port associated with that source and destination IP address pair.

Packets flow from top to bottom down the stack, like sand in an hour glass.  Then, on the receiver side, if the hourglass is reversed,  packets flow up the stack, like sand flowing in the opposite direction.

Neither telecommunications services (broadly) nor information services; the FCC's jurisdiction is only on over-the-air (e.g., wireless) links.

Both telecommunications services and information services.

Telecommunication services.

Information services.