Network+ Chapter 8 definitions

is just a relative value that defines the "cost" of using this route.

The unique protocol used by cable modem networks.

A network technology that runs at speeds between 25 and 622 Mbps using fiber-optic cabling or CAT 5 or better UTP.

An extremely efficient data transmission technique used to send digital information such as voice, data, LAN, and WAN traffic quickly and cost-efficiently to many destinations from one port.

That portion of a computer through which a peripheral device may communicate.  Often identified with the various plug-in jacks on the back of your computer.  On a network hub, it is the connect that receives the wire link from a node.  In TCP/IP, ports are 16-bit numbers between 0 and 65535 assigned to a particular TCP/IP session.

A means of translating a system's IP address into another IP before sending it out to a larger network.  NAT manifests itself by NAT program that runs on a system or a router.  A network using NAT provides the systems on the network with private IP addresses.  The system running the NAT software has two interfaces: one connected to the network and the other connected to the larger network.

The NAT program takes packets from the client systems bound for the larger network and translates their internal private IP addresses to its own public IP address, enabling many systems to share a single IP address.

The most commonly used form of Network Address Translation, where NAT uses port numbers to map traffic from specific machines in the network.

A type of NAT that maps a single routable IP address to a single machine, allowing you to access that machine from outside the network.

Preventing the passage of any IP packets through any ports other than the ones prescribed by the system administrator.

Process by which routers in a internetwork automatically exchange information with other routers.  Requires a dynamic routing protocol, such as OSPF or RIP

A protocol that supports the building of automatic routing tables, such as OSPF or RIP.

The passage of a packet through a router

Set of routing protocols that calculates the total cost to get to a particular network ID and compares that cost to the total cost of all the other routes to get to that same network ID.

The first version of RIP, which had several shortcomings, such as maximum hop count of 15 and a routing table update interval of 30 seconds, which was a problem because every router on a network would send out its table at the same time.

The current version of RIP.  Fixed many problems of RIPv1, but the maximum hop count of 15 still applies.

One or more networks that are governed by a single protocol within that AS, which provides routing for the Internet backbone.

Autonomous Systems do not use IP addresses,but rather a special globally unique Autonomous System Number assigned by the IANA(Internet Assigned Numbers Authority).  Originally a 16-bit number, the current ASNs are 32 bits, displayed as two 16-bit numbers separated by a dot. So, 1.33457 would be a typical ASN.

An exterior gateway routing protocol that enables groups of routers to share routing information so that efficient, loop-free routes can be established

Type of dynamic routing protocol that announces only changes to routing tables, as opposed to entire routing tables. 

An interior gateway routing protocol developed for IP networks based on the shortest path first or link-state algorithm.  Most commonly used IGP on the Internet.

Address assigned to routers in an OSPF network to prevent flooding beyond the routers in that particular network.

The main router in an OSPF network that relays information to all other routers in the area.

A second router set to take over if the designated router fails. 

Cisco's proprietary hybrid protocol that has elements of both distance vector and link state routing.

The next router a packet should go to at any given point.

Protocol similar to, but not as popular as, OSPF, but with support for IPv6 since inception.

Networking devices, such as routers and advanced switches, that must be configured to use.

Tools that enable you to describe, visualize, and configure an entire network.

A measure of a signal's delay.

Specifies the largest size of a data unit in a communications protocol, such as Ethernet.

(Original Equipment Manufacturer)