4.1-5. Best effort service. Which of the following quality-of-service guarantees are part of the Internet’s best-effort service model? Check all that apply. Group of answer choicesGuaranteed delivery time from sending host to receiving host.None of the other services listed here are part of the best-effort service model. Evidently, best-effort service really means no guarantees at all!In-order datagram payload delivery to the transport layer of those datagrams arriving to the receiving host.Guaranteed delivery from sending host to receiving host.A guaranteed minimum bandwidth is provided to a source-to-destination flow of packets

Check all of the services below that are provided by the TCP protocol.Group of answer choicesA guarantee on the minimum amount of throughput that will be provided between sender and receiver.In-order data deliveryA byte stream abstraction, that does not preserve boundaries between message data sent in different socket send calls at the sender.A message abstraction, that preserves boundaries between message data sent in different socket send calls at the sender.A guarantee on the maximum amount of time needed to deliver data from sender to receiver.Reliable data delivery.A congestion control service to ensure that multiple senders do not overload network links.A flow-control service that ensures that a sender will not send at such a high rate so as to overflow receiving host buffers.

2.1-4 TCP service. When an application uses a TCP socket, what transport services are provided to the application by TCP?  Check all that apply.Group of answer choicesFlow Control. The provided service will ensure that the sender does not send so fast as to overflow receiver buffers.Throughput guarantee. The socket can be configured to provide a minimum throughput guarantee between sender and receiver.Real-time delivery. The service will guarantee that data will be delivered to the receiver within a specified time bound.Best effort service.  The service will make a best effort to deliver data to the destination but makes no guarantees that any particular segment of data will actually get there.Congestion control.  The service will control senders so that the senders do not collectively send more data than links in the network can handle.Loss-free data transfer. The service will reliably transfer all data to the receiver, recovering from packets dropped in the network due to router buffer overflow.

One of the services provided by TCP is reliable data delivery.  We know from lecture that reliable delivery does not mean an absolute 100% guarantee that nothing will ever go wrong. Which of the following are services that TCP attempts to ensure (select all that apply)?Group of answer choicesTransmitted data is guaranteed to arrive at the destination.The sender and receiver will be notified if data is lost in transmission and can not be recovered.TCP can detect if data is intentionally altered during transmission and if it is altered TCP will not deliver the data.TCP ensures data will arrive at the receiver in the same order it was sent.TCP can detect if data is accidentally corrupted during transmission and if it is TCP will not deliver the data.

.1-3 UDP service. When an application uses a UDP socket, what transport services are provided to the application by UDP? Check all that apply.Group of answer choicesCongestion control.  The service will control senders so that the senders do not collectively send more data than links in the network can handle.Real-time delivery. The service will guarantee that data will be delivered to the receiver within a specified time bound.Best effort service.  The service will make a best effort to deliver data to the destination but makes no guarantees that any particular segment of data will actually get there.Loss-free data transfer. The service will reliably transfer all data to the receiver, recovering from packets dropped in the network due to router buffer overflow.Flow Control. The provided service will ensure that the sender does not send so fast as to overflow receiver buffers.Throughput guarantee. The socket can be configured to provide a minimum throughput guarantee between sender and receiver.

Unreliable service           Connectionless service           Connection-oriented service           Best-Effort service