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55 terms

Cisco - Chapter 6 Terms

I used my Network Fundamentals book to get the terms and definitions.
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Address Pool
The range of IP addresses that can be assigned the DHCP server.
Administratively Scoped Address
An IPv4 multicast address that is restricted to a local group or organization.
AND
One of three basic binary logic operations. ANDing yields the following results: 1 AND 1 = 1, 1 AND 0 =0, 0 AND 1 = 0, 1 AND 0 =0.
Broadcast Address
An address used to represent a transmission from one device to all devices.
Classful Addressing
A unicast IP address that is considered to have three parts: a network part, a subnet part, and a host part. The term refers to the fact that the network rules are first applied to the address, and then the rest of the address can be separated into a subnet and host part to perform subnetting.
Classless Addressing
An IPv4 addressing scheme that uses a subnet mask that does not follow the address limitations. It provides increased flexibility when dividing ranges of IP addresses into separate networks.
Digital Logic
Also known as Boolean Algebra. These consist of the AND, OR, and IF operations.
Directed Broadcast
A term that describes IPv4 packets sent to all hosts in a particular network. In a directed broadcast, a single copy of the pack is routed to the specified network, where it is broadcast to all hosts on that network.
Dotted Decimal
A convention for writing IP addresses with four decimal numbers, ranging from 0 to 255, with each octet - each decimal number- representing 8 bits of the 32-bit IP address. The term originates from the fact that each of the four decimal numbers is separated by a period or dot.
Global Scoped Addresses
Unique addresses that are public domain addresses. The globally scoped addresses are 224.0.1.0 to 238.255.255.255. They can be used to multi-cast data across the Internet. For example, 224.0.1.1 has been reserved for Network Time Protocol (NTP)to synchronize the time-of-day clocks of network devices.
High-Order Bit
The portion of a binary number that carries the most weight, the one written farthest to the left. High-order bits are the 1's in the network mask.
Internet Backbone
A high-speed line or series of connections that forms a major pathway within a network. The term is often used to describe the main network connections comprising the Internet.
Internet Control Message Protocol (ICMP)
As part of the TCP/IP Internet Layer, ICMP defines protocol messages used to inform network engineers of how well an internetwork is working. For example, the ping command sends ICMP messages to determine whether a host can send packets to another host.
Limited Broadcast
A broadcast that is sent to a specific network or series of networks.The IPv4 multicast addresses 224.0.0.0 to 224.0.0.255 are reserved link-local addresses.
These addresses are used for multicast groups on a local network. Packets to these destinations are always transmitted with a Time to Live (TTL) value of 1. Therefore, a router that
connects the local network should never forward them outside the local network.
Link-Local Address
An IPv4 address in the range of 169.254.1.0 to 169.254.254.255. Communication using these addresses is used with a TTL of 1 and limited to the local network.
Loopback
A special reserved IPv4 address, 127.0.0.1, that can be used to test TCP/IP applications. Packets sent to this address by a computer never leave the computer or even require a working NIC. Instead, the packet is processed by IP at the lowest layer and is then sent back up the TCP/IP stack to another application on that same computer.
Low-Order Bit
This bit represents the 0 in the binary number. In an IP subnet mask, the low-order bits represent the host position. Sometimes, it is called the host portion of bits.
Most Significant Bit
The bit position in a binary number having the greatest value. The most significant bit is sometimes referred to as the leftmost bit.
Multicast Client
A member of a multicast group. Every multicast client in each group has the same IP address. Multicast addresses begin with 224.#.#.# and end with 239.#.#.#.
Multicast Group
A group that receives a multicast transmission. The members of a multicast group have the same multicast IP addressing to receive the same transmission. It is known as a one-to-many transmission.
Network Address Translation (NAT)
Translation of RFC 1918 addresses to public domain addresses. Because RFC 1918 addresses are not routed on the Internet, hosts accessing the Internet must use public domain addresses.
Network Time Protocol (NTP)
A protocol for synchronizing the clocks of computer systems over packet-switched data networks. NTP uses UDP port 123 as its transport layer.
Positional Notation
Sometimes called a place-value notation, this is a numerical system in which each position is related to the next by a constant multiplier, a common ratio, called the base or radix. We use base-2 for computing purposes.
Prefix Length
In IP subnetting, this refers to the portion of a set of IP addresses whose value must be identical for the addresses to be in the same subnet.
Private Addresses
Defined in RFC 1918, an IP address that does not have to be globally unique because the address exists inside packets only when the packets are inside a single private IP internetwork. Private IP addresses are popularly used in most companies today, with NAT translating the private IP addresses into globally unique IP addresses.
Public Addresses
An IP address that has been registered with IANA or one of its member agencies, which guarantees that the address is globally unique. Globally unique public IP addresses can be used for packets sent through the Internet. public addressesdesignated for use in networks that
are accessible on the Internet,
Radix
The number of various unique digits, including 0, that is a positional numeral system uses to represent numbers. For example, in the binary system, base 2, the radix is 2. In the decimal system, base 10, the radix is 10.
Regional Internet Registries (RIR)
Organizations responsible for the allocation and registration of Internet number resources with in a particular region of the world.
AfriNIC (African Network Information Centre) Africa Region
APNIC (Asia Pacific Network Information Centre) Asia/Pacific Region
Reserved Link-Local Address
The IPv4 multicast addresses 224.0.0.0 to 224.0.0.255. These addresses are to be used for multicast groups on a local network. Packets to these destinations are always transmitted with a Time to Live - TTL - value of 1.
Round-Trip Time (RTT)
The time required for some networking PDUs to be sent and received, and a response PDU to be sent and received. In other words, the time between when a device sends data and when the same device receives a response.
Scope
The extent of a certain item. For example, an address scope is also known as a range of addresses from the beginning of the range to the end.
Slash Format
A method of expressing a network prefix. It uses a forward slash (/) followed by the network prefix. For example, 192.168.254.0 /24. This /24 represents the 24-bit network prefix in slash format.
Test-Net Addresses
The IPv4 address block 192.0.2.0 to 192.0.2.255. This is a slash 24 network that is set aside for teaching and learning purposes. These addresses can be used in documentation and network examples.
Limited-Scope Address
An IPv4 multicast address that is restricted to a local group or organization.
Regional Internet Registries (RIR)
ARIN (American Registry for Internet Numbers) North America
LACNIC (Regional Latin-American and Caribbean IP Address Registry) Latin Amerian and sone Caribbean Islands
RIPE NCC (Reseaux IP Europeans) Europe, the Middle East
Types of Addresses in an IPv4 Network Range
Within each IPv4 network, there are three types of addresses:
■ Network address:A special address that refers to the network
■ Broadcast address:A special address used to send data to all hosts in the network
■ Host addresses:The unicast addresses assigned to the end devices in the network
Within each network, there are two addresses that cannot be assigned to devices: network
address and broadcast address.
Private Addresses
Blocks of addresses that require limited or no Internet access.
The private address blocks are
■ 10.0.0.0 /8 (10.0.0.0 to 10.255.255.255)
■ 172.16.0.0 /12 (172.16.0.0 to 172.31.255.255)
■ 192.168.0.0 /16 (192.168.0.0 to 192.168.255.255)
Planning to Address the Network
Preventing duplication of addresses
■ Providing and controlling access
■ Monitoring security and performance
Tier 1 ISP
These ISPs are large national or international
ISPs directly connected to the Internet backbone. The customers of tier 1 ISPs are either
lower-tiered ISPs or large companies and organizations. Because they are at the top of
Internet connectivity, they engineer highly reliable connections and services.Examples include Sprint, and Savvis.
Tier 2 ISP
nLayer, France Telecom
Tier 3 ISP
Beachcomputers, Fortress ITX
ISP Tiers
ISPs are designated by a hierarchy based on their level of connectivity to the Internet back-bone. Each lower tier obtains connectivity to the backbone through a connection to a higher-tier ISP.
Tier 1 ISP Pros and Cons
Pros - The primary advantages for customers of tier 1 ISPs are reliability and speed. Because these
customers are only one connection away from the Internet, there are fewer opportunities for
failures or traffic bottlenecks
Cons -High cost of service.
Tier 2 ISP
Tier 2 ISPs acquire their Internet service from tier 1 ISPs. Tier 2 ISPs generally focus on
business customers and usually offer more services than the other two tiers of ISPs. Tier 2
ISPs tend to have the IT resources to operate their own services such as DNS, e-mail
servers, and web servers.
Tier 3 ISP
Tier 3 ISPs purchase their Internet service from tier 2 ISPs. The focus of these ISPs is the
retail and home markets in a specific locale. Tier 3 customers typically do not need many of
the services required by tier 2 customers. Their primary need is connectivity and support.
These customers often have little or no computer or network expertise.
Tier 2 ISP Pros and Cons
Pros - DNS, e-mail
servers, and web servers. Other services that tier 2 ISPs can offer include website develop-ment and maintenance, e-commerce/e-business, and VoIP.
Cons - Slower Internet access
Poor connection reliability than Tier 1 ISPs
Tier 3 ISP Pros and Cons
Pros - Good choices for small to medium sized businesses
Cons - Reduced bandwidth and reduced reliability.
Unicast
The process of sending a packet from one host to an individual host.
Broadcast
A form of transmission where one
device transmits to all devices within the network or
on another network.
Multicast
The process of sending a packet from one host to a selected group of hosts.
Multicast Client
A member of a multicast group.
Every multicast client in each group has the same IP
address. Multicast addresses begin with 224.*.*.*and end with 239.*..and end with 239.addresses begin with 224.*.*.*and end with 239.*...
Classful Addressing
A unicast IP address that is
considered to have three parts: a network part, a sub-net part, and a host part. The term classfulrefers to
the fact that the classful network rules are first
applied to the address, and then the rest of the
address can be separated into a subnet and host part
to perform subnetting.
Variable Length Subnet Mask - VLSM
This addressing scheme enables you to maximize addressing while minimizing
waste. This is less wasteful than the fixed-size block approach.
Non-VLSM Allocation Method
all subnets use the same prefix length and the same number of host bits.
Variable Length Subnet Mask Allocation Method
This method assigns the prefix and host bits to each
network based on the number of hosts in that network.