Flashcards in Chapter 5 - Sheet1 Deck (45):
Two important functions of the transport layer
Error recovery, flow control
What layer number is the transport layer
Advantage of UDP over TCP
Fewer services means less overhead
VoIP uses ___ as a transport layer protocol because ____
UDP because it does not need error recovery
Features of TCP
Multiplexing using ports, error recovery, flow control via windowing, connection establishment & termination, ordered data transfer and data segemtnation
Multiplexing using ports
Feature of TCP AND UDP: Allows receiving hosts to choose the correct application for which the data is destined, based on the port number.
Feature of TCP. Process of numbering and acknowledging data with sequence and acknow2legement header fields
Flow control via windowing
process that uses window sizes to protect buffer space and routing devices from being overloaded with traffic.
Connection establishment and termination
Process used to initialize port numbers and sequence and acknolegement fields
Ordered data transfer and data segmentation
Continuous stream of bytes from an upper-layer process that is "segmented" for transmission and delivered to upper-layer processes at the receiving device, with the bytes in the same order
RFC number of TCP
AKA Layer4PDU / L4PDU - Message created by TCP that begins with the TCP header, followed by application data
3 Things That make up a "socket"
IP address, transport protocol, port number. Example: 10.1.1.2, TCP, port 80
Location of well-known port numbers and their services
FTP Data - Port & protocol
FTP control - Port & protocol
SSH - Port & protocol
Telnet - Port & protocol
SMTP - Port & protocol
DNS - Port & protocol
53, TCP or UDP
DHCP - Port & protocol
67, 68, UDP
TFTP - Port & protocol
HTTP (WWW) - Port & protocol
POP3 - Port & protocol
SNMP - Port & protocol
SSL - Port & protocol
The process by which a connection-oriented protocol creates a connection. With TCP, a
connection is established by a three-way transmission of TCP segments - syn, syn/ack, syn
Meaning behind "SYN"
Synchronize the sequence numbers
TCP connection termination looks like --
PC1 > PC2: ACK, FIN / PC2 > PC1 ACK / PC2 > PC1 ACK, FIN / PC1 > PC2 ACK
A protocol that requires an exchange of mesages before data transfer begins, or that has a required preestablished correlation between endpoints
Protocol that does not require an exchange of messages and that does not require a preestablished correlation between two endpoints
Quality of Service - Defines the quality of the data transfer between two applications and in the network as a whole.
Four competing characteristics of QoS
Bandwidth, Delay, Jitter, Loss
Bandwidth, in relation to QoS
The volume of bits per second needed for the application to work well; it can be
biased with more volume in one direction, or balanced.
Delay, in relation to QoS
The amount of time it takes one IP packet to flow from sender to receiver
Jitter, in relation to QoS
Variation / deviation in the delay
Loss, in relation to QoS
The percentage of packets discarded by the network before they reach the destination,
which when using TCP, requires a retransmission.
3 general categories of applications
batch, interactive, and real-time
Rank batch, interactive, and real-time applications in terms of QoS needs, lowest to highest
Batch, Interactive, and real-time
Software, running on a computer, that stores web pages and sends those web pages to web clients
(web browsers) that request the web pages.
Web browser AKA
Web client, b/c they obtain a servie from a web server
Uniform Resource Locator. A standard for how to refer to any piece of information retrievable
via a TCP/IP network, most notably used to identify web pages.
Where is the protocol used by a URL referrenced in the URL
before the two // (example: http in http://www.google.com
HTTP return code 200
"ok" - returns this after an HTTP GET response is received. Sends with requested file contents