Chapter 5, Review Question R3
What are some of the possible services that a link layer protocol can offer to the network layer? Which of these link layer services have corresponding services in IP? In TCP.
Asides the basic service provided by the link layer which is to move a datagram from one node to an adjacent node over a single communication link, there are other services provided by the link layer protocols. These services are as follows;
Framing: network layer datagram are enclosed by link layer protocols within a link layer frame before transmission over the link.
Reliable Delivery: The protocols provides reliable delivery service by guaranteeing to move each network layer datagram across the link without error.
Error detection and Correction: The link layer protocols provide a mechanism to detect and correct error that are incorrectly decided in the link layer hardware.
Link Access: The media access control protocol specifies the rules by which a frame is transmitted onto the link.
The reliable delivery service also have corresponding services in TCP.
Chapter 5, Review Question 4
Suppose two nodes start to transmit at the same time a packet of length L over a broadcast channel of rate R. Denote the propagation delay between the two nodes as dprop. Will there be a collision if dprop < L/R? Why or why not?
No, there will be no collision. This is because the transmission time is less than the propagation delay; so the channel will be idle by the time transmission ends and the next propagation phase begins.
Chapter 5, Review Question 9
How big is the MAC address space? The IPv4 address space? The IPv6 address space?
2^48 MAC addresses; - they are expressed in hexadecimal notation.
2^32 IPv4 addresses; - 32 bit addressing
2^128 IPv6 addresses. - 128 bit addressing