Networking: Network Layer Flashcards
Address class system
A system which defines how the global IP address space is split up
Address Resolution Protocol (ARP)
A protocol used to discover the hardware address of a node with a certain IP address
ARP table
A list of IP addresses and the MAC addresses associated with them
ASN
Autonomous System Number is a number assigned to an individual autonomous system
Demarcate
To set the boundaries of something
Demarcation point
Where one network or system ends and another one begins
Destination network
The column in a routing table that contains a row for each network that the router knows about
DHCP
A technology that assigns an IP address automatically to a new device. It is an application layer protocol that automates the configuration process of hosts on a network
Dotted decimal notation
A format of using dots to separate numbers in a string, such as in an IP address
Dynamic IP address
An IP address assigned automatically to a new device through a technology known as Dynamic Host Configuration Protocol
Exterior gateway
Protocols that are used for the exchange of information between independent autonomous systems
Flag field
It is used to indicate if a datagram is allowed to be fragmented, or to indicate that the datagram has already been fragmented
Fragmentation
The process of taking a single IP datagram and splitting it up into several smaller datagrams
Fragmentation offset field
It contains values used by the receiving end to take all the parts of a fragmented packet and put them back together in the correct order
Header checksum field
A checksum of the contents of the entire IP datagram header
Header length field
A four bit field that declares how long the entire header is. It is almost always 20 bytes in length when dealing with IPv4
IANA
The Internet Assigned Numbers Authority, is a non-profit organization that helps manage things like IP address allocation
Identification field
It is a 16-bit number that’s used to group messages together
Interface
For a router, the port where a router connects to a network. A router gives and receives data through its interfaces. These are also used as part of the routing table
Interior gateway
Interior gateway protocols are used by routers to share information within a single autonomous system
IP datagram
A highly structured series of fields that are strictly defined
IP options field
An optional field and is used to set special characteristics for datagrams primarily used for testing purposes
Network Address Translation (NAT)
A mitigation tool that lets organizations use one public IP address and many private IP addresses within the network
Next hop
The IP address of the next router that should receive data intended for the destination networking question or this could just state the network is directly connected and that there aren’t any additional hops needed. Defined as part of the routing table
Non-routable address space
They are ranges of IPs set aside for use by anyone that cannot be routed to
Padding field
A series of zeros used to ensure the header is the correct total size
Protocol field
A protocol field is an 8-bit field that contains data about what transport layer protocol is being used
Routing protocols
Special protocols the routers use to speak to each other in order to share what information they might have
Service type field
A eight bit field that can be used to specify details about quality of service or QoS technologies
Static IP address
An IP address that must be manually configured on a node
Subnet mask
32-bit numbers that are normally written as four octets of decimal numbers
Subnetting
The process of taking a large network and splitting it up into many individual smaller sub networks or subnets
Time-To-Live field (TTL)
An 8-bit field that indicates how many router hops a datagram can traverse before it’s thrown away
Total hops
The total number of devices data passes through to get from its source to its destination. Routers try to choose the shortest path, so fewest hops possible. The routing table is used to keep track of this
Total length field
A 16-bit field that indicates the total length of the IP datagram it’s attached to
