Chapter 3 Flash Cards - LANs
Provide the following information about Ethernet:
- Speed
- Alternative Name
- IEEE Standard
- Cable type
- Maximum Length.
- 10 Mbps
- 10BASE-T
- IEEE 802.3
- Copper
- 100 m
Provide the following information about Fast Ethernet:
- Speed
- Alternative Name
- IEEE Standard
- Cable type
- Maximum Length.
- 100 Mbps
- 100BASE-TX
- IEEE 802.3u
- Copper
- 100 m
Provide the following information about Gigabit Ethernet:
- Speed
- Alternative Name
- IEEE Standard
- Cable type
- Maximum Length.
- 1000 Mbps
- 1000BASE-T
- IEEE 802.3ab
- Copper
- 100 m
Provide the following information about Gigabit Ethernet (Fiber):
- Speed
- Alternative Name
- IEEE Standard
- Cable type
- Maximum Length.
- 1000 Mbps
- 1000BASE-LX, 1000BASE-SX
- IEEE 802.3z
- Fiber
- 550 m (SX), 5 km (LX)
Basically, the CSMA/CD algorithm can be summarized as follows:
- A device that wants to send a frame waits until the LAN is silent–in other words, no frames are currently being sent–before attempting to send an electrical signal.
- If a collision still occurs, the devices that caused the collision wait a random amount of time and then try again.
What order pinout is TIA Standard T568A?
- G/W
- Green
- O/W
- Blue
- Blue/W
- Orange
- Brown/W
- Brown
What order pinout is TIA Standard T568B?
- O/W
- Orange
- G/W
- Blue
- Blue/W
- Green
- Brown/W
- Brown
Explain the Ethernet Straight-Through Cable Concept
An Ethernet Straight-Through cable connects the wire at pin 1 on one end of the cable to pin 1 at the other end of the cable the wire at pin 2 needs to connect to pin 2 on the other end of the cable; pin 3 on one end connects to pin 3 on the other; and so on. (To create a straight-through cable, both ends of the cable use the same EIA/TIA pinout standard on each end of the cable.) A straight-through cable is used to connect dissimilar devices to one another.
Explain the Ethernet Crossover Cable Concept
You swap pins 1/3 and 2/6. A crossover cable is used to connect similar devices to one another.
Which pin pairs are used for sending and receiving for the following device?PC NICs
Transmit: 1/2
Receive: 3/6
Which pin pairs are used for sending and receiving for the following device?Routers
Transmit: 1/2
Receive: 3/6
Which pin pairs are used for sending and receiving for the following device?Wireless Access Point (Ethernet Interface)
Transmit: 1/2
Receive: 3/6
Which pin pairs are used for sending and receiving for the following device?Networked Printers (Printers that connect directly to the LAN)
Transmit: 1/2
Receive: 3/6
Which pin pairs are used for sending and receiving for the following device?Hubs
Transmit: 3/6
Receive: 1/2
Which pin pairs are used for sending and receiving for the following device?Switches
Transmit: 3/6
Receive: 1/2
Explain the 6 steps of CSMA/CD Logic.
- A device with a frame to send listens until the Ethernet is not busy.
- When the Ethernet is not busy, the sender(s) begin(s) sending the frame.
- The sender(s) listen(s) to make sure that no collision occurred.
- If a collision occurs, the devices that had been sending a frame each send a jamming signal to ensure that all stations recognize the collision.
- After the jamming is complete, each sender randomizes a timer and waits that long before trying to resent the collided frame.
- When each random timer expires, the process starts over with Step 1.
Explain the structure of Unicast Ethernet Addresses
First Half:
Organizationally Unique Identifier (OUI)
Size: 24 bits / 6 Hex Digits (i.e. 00 60 2F)
Second Half:
Vendor Assigned (NIC Cards, Interfaces)
Size: 24 bits / 6 Hex Digits (i.e. 3A 07 BC)
Define: MAC
Media Access Control. 802.3 (Ethernet) defines the MAC sub layer of IEEE Ethernet
Define: Ethernet address, NIC address, LAN address
Other names often used instead of MAC address. These terms describe the 6-byte address of the LAN interface card.
Define: Burned-in Address
The 6-byte address assigned by the vendor making the card.
Define: Unicast Address
A term for a MAC that represents a single LAN interface.
Define: Broadcast Address
An address that means “all devices that reside on this LAN right now.”
Define: Multicast Address
On Ethernet, a multicast address implies some subset of all devices currently on the Ethernet LAN.
Define: 1000BASE-T
A name for the IEEE Gigabit Ethernet standard that uses four-pair copper cabling, a speed of 1000 Mbps (1 Gbps), and a maximum cable length of 100 meters.
Define: 100BASE-TX
A name for the IEEE Fast Ethernet standard that uses two-pair copper cabling, a speed of 100 Mbps, and a maximum cable length of 100 meters.
Define: 10BASE-T
The 10 Mbps baseband Ethernet specification using two pairs of twisted-pair cabling (Categories 3,4, or 5): One pair transmits data and the other receives data. 10BASE-T, which is part of the IEEE 802.3 specification, has a distance limits of approximately 100 m (328 feet) per segment.
Define: Crossover Cable
An Ethernet cable that swaps the pair used for transmission on one device to a pair used for receiving on the device on the opposite end of the cable. In 10BASE-T and 100BASE-TX networks, this cable swaps the pair at pins 1,2 to pins 3,6 on the other end of the cable, and the pair at pins 3,6 to pins 1,2 as well.
Define: CSMA/CD
Carrier Sense Multiple Access Collision Detect.A media-access mechanism in which devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. If two devices transmit at once, a collision occurs and is detected by all colliding devices. This collision subsequently delays re-transmissions from those devices for some random length of time.
Define: Full Duplex
Generically, any communication in which two communicating devices can concurrently send and receive data. In Ethernet LANs, the allowance for both devices to send and receive at the same time, allowed when both devices disable their CSMA/CD logic.
Define: Half Duplex
Generically, any communication in which only one device at a time can send data. In Ethernet LANs, the normal result of the CSMA/CD algorithm that enforces the rule that only one device should send at any point in time.
Define: Hub
A LAN device that provides a centralized connection point for LAN cabling, repeating any received electrical signal out all other ports, thereby creating a logical bus. Hubs do not interpret the electrical signals as a frame of bits, so hubs are considered to be Layer 1 devices.
Define: Pinout
The documentation and implementation of which wires inside a cable connect to each pin position in any connector.
Define: Protocol Type Field
A field in a LAN header that identifies the type of header that follows the LAN header. Includes the DIX Ethernet Type field, the IEEE 802.2 DSAP field and the SNAP protocol Type Field.
Define: Shared Ethernet
An Ethernet that uses a hub, or even the original coaxial cabling, which results in the devices having to take turns sending data, sharing the available bandwidth.
Define: Straight-through Cable
In Ethernet, a cable that connects the wire on pin 1 on one end of the cable to pin 1 on the other end of the cable, pin 2 on one end to pin 2 on the other end, and so on.
Define: Switch
A network device that filters, forwards, and floods Ethernet frames based on the destination address for each frame.
Define: Switched Ethernet
An Ethernet that uses a switch, and particularly not a hub, so that the devices connected to one switch port do not have to contend to use the bandwidth available on another port. This term contrasts with shared Ethernet, in which the devices must share bandwidth, whereas switched Ethernet provides much more capacity, as the devices do not have to share the available bandwidth.
Define: Twisted Pair
Transmission medium consisting of two insulated wires, with the wires twisted around each other in a spiral. An electrical circuit flows over the wire pair, with the current in opposite directions on each wire, which significantly reduces the interference between the two wires.
