Chapter 4: IPv4 Routing & Addressing Flashcards
The process of hosts and routers forwarding IP packets (Layer 3 PDUs), while relying on the underlying LANs and WANs to forward the bits.
IP Routing
Addresses used to identify a packet’s source and destination host computer. Addressing rules also organize addresses into groups, which greatly assists the routing process.
IP addressing
A protocol that aids routers by dynamically learning about the IP address groups so that a router knows where to route IP packets so that they go to the right destination host.
IP routing protocol
Name two functions of OSI Layer 3 protocols?
Logical Addressing & Path Selection
What does a router normally use when making a decision about routing TCP/ IP packets?
Destination IP address
What are two functions of a routing protocol?
Learning and advertising routes to neighbouring routers.
How many bits is an IP address and in what format?
32 bits in for 8 bit decimal separated groups.
A packet with a destination IP address not within the senders subnet is directed where?
The default gateway.
Upon receipt of a frame a router examines the data-link Frame Check Sequence for what purpose?
Error Detection.
How does a router primarily find the best route for an IP packet?
By consulting its routing table.
To make a decision about IP packet routing what two pieces of information could a router find in its routing table?
The outgoing interface and possibly the next-hop router IP address.
After a route is chosen what is the final step a router carries out before forwarding an IP packet?
The router encapsulates the IP packet inside a new data-link header and trailer.
What are the four steps a router carries out during IP Packet forwarding?
Error detection, removal of data-link header and trailer, route identification, re-encapsulation.
A generic reference to any routing protocol’s messages in which it sends routing information to a neighbor.
A routing update.
An application layer protocol used throughout the Internet for translating host names into their associated IP addresses.
DNS Domain Name System
An Internet protocol used to map an IP address to a MAC address. Defined in RFC 826.
ARP Address Resolution Protocol.
An Internet Control Message Protocol (ICMP) echo message and its reply; this is often used in IP networks to test the reachability of a network device.
Ping.
The format used for IP version 4 addresses, in which four decimal values are used, separated by periods.
DDF Dotted Decimal Format
The version of the Internet Protocol defined in an old RFC 791, standardized in 1980, and used as the basis of TCP/ IP networks and the Internet for over 30 years.
IPv4
An IP address that represents a single interface. In IPv4, these addresses come from the Class A, B, and C ranges.
Unicast IP address.
The process of subdividing a Class A, B, or C network into smaller groups.
Subnetting.
A list of routes in a router, with each route listing the destination subnet and mask, the router interface out which to forward packets destined to that subnet, and as needed, the next-hop router’s IP address.
Routing Table.
A set of messages and processes with which routers can exchange information about routes to reach subnets in a particular network.
Routing protocol.
