ISM 4220 EXAM 2 STUDY GUIDE
TCP/IP - Answers - Tranmission Control Protocol / Internet Protocol
Most Common
Efficient & error free
Transport Layer - Answers - (Process to Process)
Link application layer to network
Segmenting: break long message into smaller
Network Layer - Answers - (Host to host, source to destination)
Routing: determine next computer to which message should be sent
Addressing: find address of next computer
Which application layer program to send message to? - Answers - Port Numbers
Located in TCP header fields
Socket - Answers - = IP Address + Port Number
Applications can have multiple sockets
Should be assigned to TCP session
Transport Layer needs pair of sockets
Server = permanent unique port #
Segmenting - Answers - Break message from application layer into smaller PDU's
Sequence # & ACK #
Reconstructing in proper order at end
Protocol Data Units (PDU's) - Answers - All layers (except physical) add PDU's to the
message
-Segment (Transport)
-Packet (Network)
-Frame (Data Link)
Session Management - Answers - Establish end to end connection
Connectionless vs. Connection-Oriented
Connectionless - Answers - User Datagram Protocol (UDP)
NO distinct open/closings
Packets sent independently of each other
UDP: Streaming media, teleconference, DNS
Connection-Oriented - Answers - Transmission Control Protocol (TCP)
Distinct open/closings
TCP asks IP to route all packets in a message using the same route
, Handshaking
TCP: HTTP, FTP, SMTP
TCP - Answers - Connection Oriented
Reliable, in order byte-stream transfer
Sender won't overwhelm receiver
Checksum error
Numbering - Answers - TCP Feature
Software keeps track of segment being transmitted/received
Sequence & ACK
Three Way Handshake - Answers - TCP
Transport layer on both sender/receiver SYN (sync) & ACK (acknowledge)
TCP asks IP to send on same route
SYN Flooding Attack - Answers - Attacker sends large number of SYN segments
Server tries to accommodate the requests and may crash due to overload
Type of denial of service attack
TCP Safe & Sound - Answers - Guarantees that no out of order segment makes it to the
process
Lost/corrupt data = discarded
ACK retranmission sent to sender
Retransmission timer or duplicate ACK
TCP Flow Control - Answers - Regulates amount of data source can send before
receiving ACK from destination
Sliding Window Protocol
Byte-oriented, size variable
Bytes inside the window are the bytes that can be in transit
Can be sent WITHOUT worrying about the ACK
More efficient
= smaller of 1) receiver window or 2) congestion window
What is the value of the receiver window for host A if the receiver, host B, has a buffer
size of 5000 bytes and 1000 bytes of received and unprocessed data? - Answers - The
value of rwnd = 5000 - 1000 = 4000. Host B can receive only 4000 bytes of data before
overflowing its buffer
What is the size of the window for host A if the
value of rwnd is 9 bytes and the value of cwnd is
20 bytes? - Answers - The size of the window is the smaller of rwnd
and cwnd, which is 9 bytes
UDP - Answers - Connectionless, no ACK, simple
TCP/IP - Answers - Tranmission Control Protocol / Internet Protocol
Most Common
Efficient & error free
Transport Layer - Answers - (Process to Process)
Link application layer to network
Segmenting: break long message into smaller
Network Layer - Answers - (Host to host, source to destination)
Routing: determine next computer to which message should be sent
Addressing: find address of next computer
Which application layer program to send message to? - Answers - Port Numbers
Located in TCP header fields
Socket - Answers - = IP Address + Port Number
Applications can have multiple sockets
Should be assigned to TCP session
Transport Layer needs pair of sockets
Server = permanent unique port #
Segmenting - Answers - Break message from application layer into smaller PDU's
Sequence # & ACK #
Reconstructing in proper order at end
Protocol Data Units (PDU's) - Answers - All layers (except physical) add PDU's to the
message
-Segment (Transport)
-Packet (Network)
-Frame (Data Link)
Session Management - Answers - Establish end to end connection
Connectionless vs. Connection-Oriented
Connectionless - Answers - User Datagram Protocol (UDP)
NO distinct open/closings
Packets sent independently of each other
UDP: Streaming media, teleconference, DNS
Connection-Oriented - Answers - Transmission Control Protocol (TCP)
Distinct open/closings
TCP asks IP to route all packets in a message using the same route
, Handshaking
TCP: HTTP, FTP, SMTP
TCP - Answers - Connection Oriented
Reliable, in order byte-stream transfer
Sender won't overwhelm receiver
Checksum error
Numbering - Answers - TCP Feature
Software keeps track of segment being transmitted/received
Sequence & ACK
Three Way Handshake - Answers - TCP
Transport layer on both sender/receiver SYN (sync) & ACK (acknowledge)
TCP asks IP to send on same route
SYN Flooding Attack - Answers - Attacker sends large number of SYN segments
Server tries to accommodate the requests and may crash due to overload
Type of denial of service attack
TCP Safe & Sound - Answers - Guarantees that no out of order segment makes it to the
process
Lost/corrupt data = discarded
ACK retranmission sent to sender
Retransmission timer or duplicate ACK
TCP Flow Control - Answers - Regulates amount of data source can send before
receiving ACK from destination
Sliding Window Protocol
Byte-oriented, size variable
Bytes inside the window are the bytes that can be in transit
Can be sent WITHOUT worrying about the ACK
More efficient
= smaller of 1) receiver window or 2) congestion window
What is the value of the receiver window for host A if the receiver, host B, has a buffer
size of 5000 bytes and 1000 bytes of received and unprocessed data? - Answers - The
value of rwnd = 5000 - 1000 = 4000. Host B can receive only 4000 bytes of data before
overflowing its buffer
What is the size of the window for host A if the
value of rwnd is 9 bytes and the value of cwnd is
20 bytes? - Answers - The size of the window is the smaller of rwnd
and cwnd, which is 9 bytes
UDP - Answers - Connectionless, no ACK, simple
