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In the 1970s, Bob Metcalfe and David Boggs invented Ethernet while working at Xerox PARC. At that time, Ethernet's top speed was 3 Megabits per second (Mbps). This version was installed in a few sites including Boeing, the White House, and various academic institutions. In the early 1980s, the original …
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The first layer of the OSI Reference Model is the physical layer. This layer describes the physical characters of the network. This layer defines the tangible aspects of the network medium, such as types of cables and pin arrangements, but it also defines how much voltage is used in copper …
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The fifth layer of the OSI Reference Model is the session layer. Since applications running on different hosts may need to establish a connection in order to operate, the session layer is responsible for setting up the connection. It is important to note that the session layer is responsible for …
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The Open Systems Interconnection (OSI) Reference Model first came into being in 1978. The OSI group was intent on getting a model into the field quickly, so they elected to adopt a seven-layer model created by Charles Bachman of Honeywell. By this time, the lower four levels of the model …
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No matter how small, all network installations go through an initial planning phase before implementation. The new network administrator must take many factors into consideration when planning a network. Most importantly, the administrator must understand the required capacity, compatibility, and flexibility of the new network. Gathering this information requires a …
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In most VPN setups, each VPN user is given unique login credentials. Very rarely, you might run into a situation where a group of individuals is going to be sharing a set of credentials. For example, you might assign VPN credentials to another company for temporary access to part of …
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There are a few network devices out there that allow you to connect, but don't give you an option to disconnect. For example, you might be stuck at a password prompt, but have no authentication details. Most telnet clients allow you to break these connections with the ^] (control-]) command. <acronym …
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You may already know that the IEEE 802.1D specification recommends a maximum network diameter of 7 hops. What you may not know is that the number 7 is derived from a series of calculations based on various timers being tuned to their default values. If you are designing a …
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I saw this error message on a Cisco ASA 5540 today:
%ASA-3-210005: LU allocate connection failed
According to Cisco, this error means the standby unit was not able to create a new connection for stateful failover. The recommendation is to verify that the system has enough RAM.
OK...
# show memory …Posted on in Networking
Intranets are privately owned networks that operate like the public Internet in many respects. In most intranets, corporate users access company information via tools designed to run in web browsers. Intranets allow employees to share and access confidential corporate information. The benefit of these systems is that they operate …
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