Easter homework

Just to keep you busy during the holidays. Homework is due May, 2nd.

1. 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?
2. 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?
3. Why is an ARP query sent within a broadcast frame? Why is an ARP response sent within a frame with a specific destination MAC address?
4. Explain what is the Exponential Binary Back-off algorithm used by Ethernet.
5. Where can you find the 802.1Q VLAN tag in the Ethernet frame format?

Last lab

There has been a delay in the development of the last lab so we are forced to keep the last year's lab but maybe other groups will use the new one. Because of that a translated version (of the old one) won't be provided this time. You can pull Lab#8 from the PoliformaT and while the program used has all the menus in English the text is not, so do not hesitate asking me for help if you have any problem.

Seventh lab: IPTABLES

You can grab the lab text here. IPTABLES is a framework to create a set of rules governing how network traffic is handled by the OS. You can think of it as a software firewall.

Next class Ethernet will be present with some detail. Please read sections 5.5 & 5.6 of the textbook.

Only one additional lab is left.  Next two lab sessions will be for presenting the programming projects. That may happen in the next two Wednesdays after lab#8 or we can use the last two weeks of the term. Is up to you. We can discuss this next Friday. Please note that what is decided will affect the due date of the programming projects.