8. Translate the passages in writing:

a) Each switch will take the packet sent by the other switch and flood it back out again immediately, since they still don't know who Node A is. Switch A will receive the packet from each segment and flood it back out on the other segment. This causes a broadcast storm as the packets are broadcast, received and rebroadcast by each switch, resulting in potentially severe network congestion.

b) Essentially, a spanning tree uses the spanning-tree algorithm (STA), which senses that the switch has more than one way to communicate with a node, determines which way is best and blocks out the other path(s). The cool thing is that it keeps track of the other path(s), just in case the primary path is unavailable.

c) A path cost value is given to each port. The cost is typically based on a guideline established as part of 802.1d. According to the original specification, cost is 1,000 Mbps (1 gigabit per second) divided by the bandwidth of the segment connected to the port.

d) The network is now configured as a single spanning tree, with the root bridge as the trunk and all the other switches as branches. Each switch communicates with the root bridge through the root ports, and with each segment through the designated ports, thereby maintaining a loop-free network.

9. Answer the following questions using the information from parts 13 and 14 of the text.

1. What causes a broadcast storm? 2. What did DEC create to prevent broadcast storms and other unwanted side effects of looping? 3. What is the function of the spanning-tree algorithm? 4. How long is the bridge ID and what does it contain? 5. What is given to each port? 6. How is the path cost value calculated according to the original specification? 7. What does each switch begin a discovery process for? 8. How do we call special network frames by way of which information is shared between all the switches? 9. What are the parts of a BPDU? 10. What does path cost to root bridge determine? 11. How is a root bridge chosen? 12. What ports are called root ports? 13. What is the difference between designated ports and non-designated ones? 14. What does STP do in case the root bridge begins to fail or have network problems?

10. Look through parts 13 and 14 of the text and mark the statements as true (t) or false (f). If you think a statement is false, change it to make it true.

1.	□	With all of the switches connected in a loop, a packet from a node could quite possibly come to a switch from two different segments.
2.	□	Receiving the packet from each segment and flooding it back out on the other segment eliminates a broadcast storm.
3.	□	To prevent broadcast storms and other unwanted side effects of looping, Microsoft Corporation created the spanning-tree protocol.
4.	□	A spanning tree uses the error-correction algorithm, which senses that the switch has more than one way to communicate with a node.
5.	□	The bridge ID is 10 bytes long and contains only the switch`s MAC address.
6.	□	According to the original specification, path cost is 1, 000 Mbps divided by the bandwidth of the segment connected to the path.
7.	□	The path cost is always one of the standard cost values and cannot be an arbitrary value assigned by the network administrator.
8.	□	All of the switches are constantly sending BPDUs to each other, trying to determine the best path between various segments.
9.	□	The switch that has the highest BID is elected by the other switches as the root bridge.
10.	□	Each switch communicates with the root bridge through the root ports, and with each segment through the non-designated ports.