Ian Reese
Lab 3: OSI Model

1. If we already had the TCP/IP model, why was the more complicated OSI model created?

2. What does the abbreviation OSI stand for? Who originated it? When?

Open Systems Interconnection. Charles Bachman provided the concept in the 1970’s and it was fully created and incorporated by the International Organization of Standardization.


Layer # Layer Name Mnemonic Keywords & Description of Function
7 Application Animals
6 Presentation Poisonous
5 Session Super
4 Transport Touch
3 Network Not
2 Data-Link Do
1 Physical Please

4. Determine the highest layer of operation for the following network devices:

Layer 1: hub, repeater, patch panel

Layer 2: bridge, NIC, wireless access point, cable media, switch

Layer 3: router, switch

5. What is another name for a physical address? How many bits do they require? When two machines attempt to transmit simultaneously on the same media segment, both messages become garbled and unintelligible. What is this condition normally called?

MAC Address. 48 bits. It is called a data collision.

6. What is your IP address? What is your MAC address? and 40-61-86-06-54-83 respectively

7. ARP ends in a “P” so what does that often signify?

That the P stands for Protocol.

What does ARP stand for & what does it do?

At the command prompt type arp –d *. This command clears your arp table. Type arp –a to verify there are currently no entries in the arp table. Now ping your neighbor’s computer by typing ping and their IP address. Did you get a reply? If not, be sure the windows firewall is turned off. Why is ping useful? Retype arp –a and record any changes. What is your neighbor’s physical address? Have your neighbor verify their physical address. Is it what is displayed in your arp table? Add two more entries to the arp table by pinging two other machines in the lab. What address is added to the arp table when you ping http://www.sal.ksu.edu? Why?

8. If a packet comes in from another network, only a layer 3 (IP) address is known. But direct machine to machine communication only occurs at layer 2. What method is used to translate a known layer 3 address into an unknown layer 2 address?


9. Network Layer Layer 3 devices allow the interconnectivity of different local area networks through gateways. What are layer 3 gateway devices called? They use logical, or software encoded addresses. Many types of software addresses have been developed and used. What is the de-facto standard for logical addresses used today? How many bits do they require?