Domain 4: Communication and Network Security 14% Flashcards
Baseband
networks have on channel, and can only send one signal at a time. Ethernet is baseband.
Broadband
networks have multiple channels and can send and receive multiple signals at a time.
Extranet
is a connection between private Intranets, often connecting business partners Intranets.
Circuit switching
Expensive, but always available, used less often. A dedicated comm channel through the network, guarantees the full bandwidth.
Packet switching
cheap, but no capacity guarantee, very widely used today.
QOS (Quality of Service)
gives specific traffic priority over other traffic. Most commonly VOIP, or other UDP traffic needing close to real time comm.
GAN (Global area network)
A global area network, is a network used for supporting mobiles users across a number of wireless LANs, satellite coverage areas, the transition from one to the next can be seamless
OSI (Open Systems Interconnect)
7 layers. 1. Physical, 2. Data Link, 3. Network, 4 Transport, 5. Session, 6. Presentation, 7. Application
7-1 All people seem to need data processing
PDU (Protocol Data Units)
Data-567, Segments-4, Packets-3, Frames-2, Bits-1
Layer 2: Data Link Layer
Transports btw 2 nodes connected to same network. LLC - Logical Link Control-error detection.
MAC address (BIA)
a unique identifier on the network card. Can be spoofed very easily. Threats - MAC Spoofing, MAC Flooding.
ARP (Address Resolution Protocol)
Layer 2/3
CSMA/CD (Collision Detection)
Ethernet - minimized with switches vs hubs.
CSMA/CA (collison Avoidence)
Wireless
Token passing
Similar to the talking stick, not really used anymore
Layer 3: Network Layer
Expands to many different nodes (IP) - The Internet is IP based. Isolates traffic into broadcast domains. Threats = Ping of Death, Ping Floods, Smurf - spoof source and directed broadcast, IP modifications, DHCP attacks
Only IMAP is layer 7 all other I protocols are Layer 3.
Layer 4: Transport Layer
SSL/TLS Layer 4 to 7
UDP (User Datagram Protocol)
Connectionless protocol, unrealiable, VOIP, Live video, gaming, “real time” Timing is more important than delivery confirmation Attack: Fraggle attack
TCP (Transmission Control Protocol)
Reliable, connection oriented, guaranteed delivery, 3 way handskake, slower/more overhead, data reassembled. Attacks: SYN floods - half open TCP sessions, client sends 1,000’s of SYN requests, but never the ACK
3-Way handshake
SYN, SYN/ACK, ACK
TCP Flags (9 bits 1-bit flags)(Control bits)
SYN= synch sequen numbers ACK= indicates that the Acknowledgment field is significant. RST= Rest the connection. FIN= Last package from sender
Layer 5: Session Layer
Establishes connection between 2 applications: Setup > Maintenance>Tear down
Layer 6: Presentation Layer
Only layer with no protocols. Formatting, compressing, encryption (file level)
Layer 7: Application Layer
Presents data to user (applications/websites. HTTPS, FTP, SNMP, IMAP, POP, AD integration