chptr13 Flashcards
NIC Network Interface Controller
serves as the hardware interface between computer and network
End to end channel
nic to cloud/sps to nic
Open Systems Interconnection Reference Model OSI
theoretical model as a standard by ISO - used for research
TCP/IP
integrated suite consisting of numerous protocols that control aspects of data communication - 5 layers: Application - Transport - Network - Data Link - Physical
Protocol Stack
each layer of the stack at the sending node contributes information that will be used by the corresponding peer layer
Program Applications
Safari - Outlook - Skype etc
Network Applications
designed to present the message to the network in a format that can be understood by each of the hardware and software components of the channel - standard protocols part of TCP/IP
Application Layer
contains the program and network applications
Ethernet
comprises layers 1 and 2 of the tcp/ip protocol suite - Physical and data link layers
frame
bits of an Ethernet packet sent through a single link from one node to another in a LAN
non-Ethernet packets
also called frames at the data link layer
not a node
hub switch or Wi-Fi access point are transparent to data being moved
Physical Layer
Level 1 - layer at which the communication actually takes place. Includes medium - signaling method - specific signal parameters - voltages - carrier frequencies - lengths of pulses etc. Sync and timing issues
Data Link layer
Level 2 - responsible for transmission and delivery of packets across the communication link between nodes. Two sublayers Medium Access Control MAC and
Logical Link Control LLC
collision
two messages collide
Carrier Sense Multiple Access with Collision Detection CSMA/CD protocol
Ethernet - connections are point to point and collisions are not possible.
MAC Address
Address for each node on the Ethernet network - permanently assigned by the IEEE org to manufacturers of Ethernet attached equipment. NIC
Network Propagation delay
the amount of time it takes for a packet to get from one end of the network to the other
WI Fi ad hoc mode
assumes direct connections between Wi-Fi nodes and is based on a partial mesh network topology. Depends on a network of available coop stations rarely is used
Wi Fi infrastructure mode
variation of CSMA/CD is used for infrastructure Wi-Fi. Collision handling is required. Delays due to collisions are much longer than those on a wired hub
Carrier Sense Multiple Access with Collision Avoidance CSMA/CA protocol
a station listens until channel clear to transmit. Then transmits frame to access point. When frame reaches its destination the receiver checks for errors then sends a short acknowledgment packet to indicate receipt
Logical Link Control (within Datalink)
resize frame if necessary optional error checking - frame numbering or reordering/recombining frames
Media Access Control (within Datalink)
add frame header. Encode bytes of frames to bits in format and signal type appropriate for medium and signal method of physical layer. On receiving message it decodes bit stream to bytes of frame and removes frame header.
The Network Layer
Layer 3 - responsible for addressing and routing of packets from the source end node through intermediate nodes - step by step - to their proper final destination.
TCP IP Network layer
aka internetworking layer or IP layer
IP datagrams
IP level packets within a LAN
Layer 3 switches
routing takes place at the network layer - routers and gateways are sometimes called this
fragments
ip datagram fragments are reassembled by IP when the final destination is reached using header info that is stored with each fragment. IPv6 rejects fragments instead