What's the Difference Between a Packet and a Frame?
When speaking of the data in a network, people often call everything a packet. A more proper generic term would be protocol data unit or PDU. The specific name for a PDU depends on at what layer the data unit is in the OSI model. More ...
TCP Windowing
It would be inefficient to return an ACK message as each segment is received. The number of segments received before an ACK message is returned is called the TCP receive window size. More ...
T-Carrier - A Complete and Comprehensive Guide
T-carrier was introduced in 1962 by AT&T Bell Laboratories. A T1 line has the capacity of transmitting 1.544 Mbps and it can also be used to send 24 digitized voice channels. Dispite its age, because of its reliability, T-carrier is the most commonly used digital transmission service in the US, Canada, and Japan. More ...
DSL (Digital Subscriber Line)
DSL (Digital Subscriber Line) is a technology used to transmit digital data over telephone lines. DSL service can be transmitted simultaneously with voice band telephone service on the same line because DSL uses a much higher frequency that rides on top of the low 3400 Hz voiceband. More ...
IPv6 Prefix Length Notation
In IPv4, the prefix (or network portion) of the address can be identified by a dotted-decimal netmask, commonly referred to as a subnet mask. IPv6 address prefixes can be represented much the same way that IPv4 address prefixes are written in CIDR notation. More ...
IPv6 Global Unicast Addresses
Global unicast addresses (GUAs) are globally routable and reachable in the IPv6 Internet; they are equivalent to public IPv4 addresses. GUA addresses are also known as aggregatable global unicast addresses. More ...
The OSI Session Layer
The Session layer, layer seven of the OSI model, establishes, synchronizes, maintains and terminates sessions between computers on a network. It establishes a connection ID and authenticates security. More ...
Routing Information Protocol (RIP), Open Shortest Path First (OSPF), and Routing Convergence
A routing protocol advertises route information between routers. Dynamic routing protocols are available that allow a router's routing table to be updated as network conditions change. More ...
IPv6 Neighbor Discovery Protocol (NDP)
Neighbor Discovery Protocol (NDP) is used by IPv6 hosts for Router Discovery, Neighbor Discovery and Duplicate Address Discovery. More ...
IPv4 Address Classes
Originally, IP network numbers were defined with rigid boundaries and grouped into address classes. Even though address classes was created to facilitate efficient use of the IPv4 address space, because of its rigidity it has been abandoned for more flexible classless addressing. More ...
The OSI Physical Layer
The Physical layer (OSI layer 1) deals with the mechanical and electrical specifications of the network hardware. Layer 1 specifications define connectors, pin-outs, signal voltages, and related software. More ...
IPv6 Unicast Addresses
The 3 categories of IPv6 addresses are:Unicast identifies a single interface. A packet sent to a unicast address is delivered to the interface identified by that address. Multicast identifies a group of interfaces. A packet sent to a multicast address is delivered to all interfaces identified by that address. Anycast identifies a group of interfaces. A packet sent to an anycast address is delivered to the closest member of a group. More ...
Internet Security and VPN Network Design
This article discusses some essential technical concepts associated with a VPN. A Virtual Private Network (VPN) integrates remote employees, company offices, and business partners using the Internet and secures encrypted tunnels between locations. More ...
T-Carrier
T-carrier is a time-division multiplexed (TDM) digital signal that has been used by the telephone companies for many decades. 24 8-bit signals are time-division multiplexed into a 1.544 Mbps t-carrier signal. More ...
Networking Routing Believability and Administrative Distance
If a network is running more than one routing protocol and a router receives two route advertisements from different routing protocols, which route advertisement does the router believe?. More ...
