Network Flashcards
What is the name given to service models transporting datagrams in the Network Layer and why is it rarely used?
Best Effort models, rarely used because it i not reliable. TCP is built on top to allow this.
What’s the best effort service for the Network layer nowadays?
IP(Internet Protocol)
What is a Virtual Circuit?
Source to destination path, behaves similar to telephone circuit. Consists of - Path - VC numbers - Entries in forwarding tables
What is the longest prefix matching algorithm?
Looks for the forwarding table entry for a given destination address.
Name 3 main network layer functions
1 Routing protocols
2 IP protocols
3 ICMP protocols
Must all interfaces be given an IP address?
Yes
Whats an interface?
Connection between host/router and physical link
What is a subnet?
A logical subdivision of an IP network
What is a VLSM?
Variable Length Subnet Masking allows you to divide an IP address space into a hierarchy of subnets without wasting large numbers of addresses.
What is a CIDR?
Classless Inter-Domain Routing is a way to allow more flexible allocation of IP addresses.
Name 2 ways to get an IP address
1- Hard coding
2- DHCP
What is DHCP?
Dynamic Host Configuration Protocol dynamically assigns IP addresses to hosts.
List the four phases of DHCP messaging and who it comes from
host: “DHCP discover”
DHCP server: “DHCP offer”
host: “DHCP request”
DHCP server: “DHCP ack”
What is IP fragmentation?
This is when IP datagram’s are divided into smaller datagrams in order to satisfy the MTU(maximum transfer unit) and then reassembled at the final destination.
Name the 3 switching(forwarding) fabrics
1 Bus
2 Memory
3 Crossbar
Name the 3 Router input port functions
1 Bit level reception
2 Data link layer
3 Queueing
What is NAT?
Network Address Translation is the process of assigning a public address to a computer(s) in a private network.
What is the NAT traversal problem?
This is when the client wants to connect to the server with a private address but the public address is the only one visible.
Name 3 solutions to the NAT traversal problem
A- Configure NAT to forward incoming connection requests at a given port to the server
B- Universal Plug and Play
C- Relaying(creating a bridge for connection)
What is Internet Control Message Protocol (ICMP)?
Used by hosts and routers to communicate network-level information
What’s IPv6?
The most recent version of IP that enables data communications over a packet switched network.
Name two methods of coping with the transition from IPv4 to IPv6
- Dual Stack
- Tunneling
What type of routing algorithm will global and decentralized networks use?
Global- Link state algorithms
Decentralized- Distance vector algorithms
What does autonomous systems mean?
To aggregate routers into regions running the same protocol
What is broadcast routing?
Delivering packets from source to all other nodes.
What is flooding?
When nodes receives broadcast packet, sends copy to all neighbors
