Pytanie  |
Odpowiedź |
|
rozpocznij naukę
|
|
translating bits from sending node into form that can be send via network
|
|
|
|
rozpocznij naukę
|
|
representation of bits transmitted over the link, so they can be delivered to the end node
|
|
|
media access control (MAC) rozpocznij naukę
|
|
how to share medium efficiently among nodes
|
|
|
|
rozpocznij naukę
|
|
Wireless network, Last-mile links networks, Local Area Networks (LAN)
|
|
|
|
rozpocznij naukę
|
|
hardware that connects a node to a link, it encodes bits into signals at the sending node and decodes signals into bits at the receiving node
|
|
|
|
rozpocznij naukę
|
|
Non-return to zero, Non-return to zero inverted, Manchester, 4B5B
|
|
|
Non-return to zero approach rozpocznij naukę
|
|
when bit is 0 then signal is low and vice versa, sequences of consecutive 0s/1s makes singnal stays low/hgih for long
|
|
|
Non-return to zero inverted approach rozpocznij naukę
|
|
bit 1 change the signal frequency (low/high)
|
|
|
|
rozpocznij naukę
|
|
0 being encoded as low-to-high transition and 1 being encoded as high-to-low transition
|
|
|
|
rozpocznij naukę
|
|
insert extra bits into the bit stream so as to break up long sequences of 0s or 1s
|
|
|
Byte oriented framing methods rozpocznij naukę
|
|
Usage of special characters (sentinel characters), Include number of bytes in the frame
|
|
|
|
rozpocznij naukę
|
|
High Data Level Control Protocol- used for transmission of bit data, ensures reliable data transfer and can operate without a continuous connection
|
|
|
|
rozpocznij naukę
|
|
when a specific sequence of bits appears in the data an extra bit is added to break the pattern, prevents the receiver from mistaking the data for control information
|
|
|
|
rozpocznij naukę
|
|
Notify the sender, to get the message again. Reconstruct the correct message by recipient
|
|
|
|
rozpocznij naukę
|
|
redundant information bits to help receiver determine if error occurs
|
|
|
|
rozpocznij naukę
|
|
achived using acknowledgments and timeouts
|
|
|
|
rozpocznij naukę
|
|
after transmitting one frame, the sender waits for an acknowledgment before transmitting the next frame. If ACK do not arrive retransmit message
|
|
|
|
rozpocznij naukę
|
|
sender assigns a sequence number to each frame and the sender maintains three variables: send window size, last ACK received and last frame send
|
|
|
|
rozpocznij naukę
|
|
device that forwards digital signal but do not understand it
|
|
|
|
rozpocznij naukę
|
|
spread the signal over a wider frequency band to minimize the impact of interference from other devices
|
|
|
spreaad spectrum techniques rozpocznij naukę
|
|
frequency hopping, direct sequence spread
|
|
|
|
rozpocznij naukę
|
|
transmition of the signal over a random sequence of frequencies
|
|
|
|
rozpocznij naukę
|
|
adds redundant bits for greater tolerance of interference
|
|
|
Endpoints in wireless networks rozpocznij naukę
|
|
Base station, Mesh networks
|
|
|
|
rozpocznij naukę
|
|
has no mobility but has a wired connection to the Internet or other networks
|
|
|
|
rozpocznij naukę
|
|
nodes are peers, there is no base station nodes
|
|
|
