ITS midterm #2, ITS exam 2
what does an ethernet bridge doe when it receives a frame intended for an address its never heard of? A) It retransmits the frame to the other side B) it puts the destination address in its address list C) it discards the frame D) None of the above
A
what are disadvantages of a token ring?
- complexities - ring initialization - additions to ring -Cost
when did divestiture occur?
1974, antitrust lawsuit against AT&T
convert 1001bin to hexadecimal and decimal
9hex, 9 dec
00:13:20:7c:30:9c is: A) a MAC address B) A gTLD C) AN IP address D) could be any of the above, depending on context
A
True or false: token ring medium access control is effective in very busy LANs because devices only transmit when they have the token
True
we discussed several companies that operation nationwide networks. name one, other than AT&T and Verizon.
Verizon, sprint, T-Mobile, and century link
Error checking
When the recipients NIC/bridge/switch recieves a frame and finds it corrupt it ignores or discards it
in the LAN world, what is a collision
a collision is simultaneous transmission by two (or more) stations on a shared medium
how do hubs, bridges, and switches differ?
bridges are predecessor to switches, bridges could support only 4 port while switches can support 24/48
what is CSMA/CD and how does it work?
carrier sense multiple access with collision detection, MAC protocol, 1 if the medium is idle, start transmission 2 if the medium is busy, wait 3 if a collision is detected, stop transmitting, then wait a random duration, then start over
whats a hub?
communication device that relays communication data, sends frames to all devices on a network regardless of MAC address
what are the concepts of a frame?
contains the MAC, tells the destination device what kind of data is in the frame.
Format of MAC address?
destination MAC address, source MAC address, Data type
True or False: Bridges are relatively stupid devices, simply retransmitting everything they receive
false
what are the advantages of a token ring?
good at high data rates predictable
why would you want a LAN?
it connects network devices over a relatively short distance,
What are LANS?
local area networks, interconnects network components within a local area
What is M&A
mergers and aquistions
what is the function of the ethernet checksum?
serves to detect transmission errors
what is a token ring?
special data packet, the token circulates around the ring, when the station receives the token the packet, it can transmit a data packet.
what is error checking?
the recipient NIC, receives a frame and finds it corrupt, it ignores and discards it.
True or False: The earliest ethernet ran on coaxial cables and topology was a bus.
true
True or false: ARPANET was a defense department project
true
true or false: AT&T is the largest provider of landline local telephone service in ohio. A key evet In bringing this about was SBC's acquisition of Ameritech.
true
an ethernet header contains: A) the destination's MAC address B) the address of the switch or hub that will transmit the frame. C) the routing table entries for the frame as it traverses the internet D) all of the above
A
True or False: an ethernet MAC address indicates the manufacturer
True
True or false: 0xA=10 dec
True
True or false: Before divestiture, the BOCs bought telephones and other equipment almost exclusively from western electric
True
True or False: CSMA/CD medium access control is ineffective in very busy LANs because frequent collisions keep any station from transmitting meaningful data
True
The Modified Final judgment was intended to encourage competition in which industry segment or segments? Mark all that are correct. A) long distance telephone service B) Equipment manufacturing C) Local Telephone service. D) Cellular service
A, B
Mac and NIC
Are like together
When AT&T was broken up, what portions of the pre-divestiture company stayed with the 'new' AT&T?
At the time of MFJ, AT&T retained long distance service and equipment manufacturing
the regional bell operating companies came into existence as a result of: A) the kingsbury commitment B) The modified Final judgment C) The telecom Act of 1996 D) The Carterfone Decision
B
what companies merged together and what did they become?
Bell Atlantic merged with NYNEX and changed its name to Verizon.
What is BOC?
Bell operating Company
Layer model
Break it appear into manageable tasks
LAN topologies
Bus star ring
The telecom act of 1996 was intended to encourage competition in which industry segment or segments? Mark all that are correct. A)Long distance telephone service B) Equipment manufacturing C) local telephone service D) cellular service
C
What does an ethernet do when it receives a frame with a transmission error? A) The receiving device makes a note of the sending devices MAC address B) the receiving device sends a message to the ethernet switch asking for the frame to be resent C) The receiving device discards the frame D) All of the above
C
CSMA/CD
Cheap simple poor performance at high data volumes
At one time or other, Ohio Bell has been owned by which of these companies? A) AT&T B) SBC C) Ameritech D) All of the above
D) All of the above
historically, several units comprised the Bell system. Which one of the following was NOT a member of the Bell system in the decades prior to divestiture? A) BOCs B) AT&T C) Western Union D) Western Electric
D) Western Union
Cloud
Data storage centralized
Frames
Ethernet devices transmit data in chunks called frames each frame has MAC address of the sending and receiving device
what's a frame?
Ethernet packets are called frames
Packets
Ethernet packets called frames IP packets called data grams
When LAN devices transmits
Every device recieves and listens for message intended for it
Sniffers
Examine everything
True or False: The "the rule of three" was part of the telecom act of 1996
False
True or false: the TA of 1996 resulted in the formation of many telephone start-up companies that have thrived and become important parts of todays telecom landscape.
False
MAC address
First 3 manufacturer like vin on car
Router
Forwards data packets between computer networks they are like traffic directions on the internet
Gateways
Interface between Ethernet LAN and the outside world is a gateway
Every transmission
Is tagged with recipient MAC address
ARP (address resolution protocol)
Maps a dynamic internet protocol IP address to a permanent physical machine address in a LAN
MAC
Medium Access Control
What is MAC?
Medium Access control, unique to a NIC,
name an RBOC (either a current one or one that's no longer extant), other than today's At&T.
NYNEX, Bell Atlantic, Bell south, Southwestern Bell, Ameritech, US west, and pacific telesis
What is NIC?
Network interface card, is the hardware in your pc that manages LAN connection
Not RBOCs?
Ohio bell, Cincinnati bell, frontier, GTE, Sprint
Token ring
Popcorn reading Great for high data rates
Encapsulation
Putting one packet into a packet of a different type
what is RBOC? and how many companies were formed and what are there names?
Regional bell operating company. 7, NYNEX, Bell Atlantic, Bell south, Ameritech, Southwestern Bell, Us West, and pacific telesis
What did southwestern bell change there name to?
SBC (southwestern Bell company)
DHCP (Dynamic Host Configuration Protocol)
Server assigns an IP address and other network configuration parameters to each device on a network so they can communicate with each other IP networks Xbox
IP header
Source address destination address
What are the various topologies?
Star topology, bus topology, ring topology, and mesh topology
Wire shark
State of art packet analysis tool
Switch vs hubs
Switches are better hubs rare now because hubs the more people the more collisions a switch is a small hardware that joins multiple computers together within one LAN hubs connect multiple Ethernet devices together making them a single segment
3 factors in ITS
Tech developments,economic market forces and government regulations
Either type
Tells destination device what kind of data is in the frame
What event allowed/ triggered the flurry of mergers and acquisitions among the RBOCs?
The telecom act of 1996 allowed the RBOC to merge/ acquire one another