Network Layer Flashcards
What is forwarding ?
The movement of a packet from the input link to the output link
What is routing and what is it done by
This is the movement of a packet around the network from source to destination and this is used using a router or switch
What is a routing algorithm?
This is a series of steps used to send packets from one end of a link to another
What types of routing algorithm are there ?
Global routing , Centralised routing and decentralised routing
How do nodes obtain an IP address ?
Using a DHCP server
What packets are sent and received from a node when requesting an IP address ?
DHCP_DISCOVER, DHCP-OFFER, DHCP-PREREQUEST, ACK
How does a private network communicate with a public network?
Using a NAT router which will use a public IP address for all nodes, this will ensure that the public internet doesn’t know the source address of a node on a private network
What is a subnet?
A subnet is a part of a larger network that is separate this is used to represent all machines in a location, this is also done so that there is a one shared connection to the public internet
What does a NAT translation table contain?
The IP address and port number of nodes that have an open TCP/UDP connection over the public internet
What is PING and what packets does it use ?
ECHO REQUEST AND ECHO REPLY, relay the time take for a packet to go around a network, will indicate a time taken, if the time is poor this will indicate issues within the network such as congestion
What are the reasons for congestion?
LARGE PACKETS, LOW MEMORY, IGNORANCE OF PACKETS, POOR ROUTING
How can you improve congestion?
Through better routing, increase memory, restrict user access, restrict packets being sent, process the remaining packets before transmitting more packets.
Why have a subnet?
SECURE, MANAGEABLE, EXPANSION
What is the range for class A ipv4 address
0-126
What is the range for class B ipv4 address
128-191
