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Posted on in Networking
In this case, gentlemen, size matters.
Yesterday, I calculated the average packet size for one of the networks I work on using data from 263986M (263,986,000,000+) packets.
Average packet size for that sample was 557 bytes.
Posted on in Networking
Although routers and switches are often located near each other in a network environment, the two devices offer very different functionality. Routers are network devices that send data packets to distinct network segments. A router examines incoming packets and makes routing decisions based on the destination address in the packet …
Posted on in Networking
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 …
Posted on in Networking
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 …
Posted on in Networking
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 …
Posted on in Networking
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 …
Posted on in Networking
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 …
Posted on in Networking
Cisco ASA limits the number of concurrent remote-access VPN sessions a user can maintain. The default is three. When a user hits the limit, a new connection can fail or an existing idle session can be removed, depending on the configured limit and session state.
The CLI knob is still …
Posted on in Networking
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 …
Posted on in networking
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 …
Posted on in Networking
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 …
Posted on in Networking
This is a revisiting of the Company X presentation regarding telecommunications.
Company X should utilize prevailing broadband technology in each store location to provide the lowest cost high-speed access to the Internet. In order to facilitate communication between each store and the company headquarters, a virtual private network (VPN …
Posted on in Networking
A buddy of mine is getting about 1 Mbps through his Cisco 2621XM based VPN.
Additionally, the CPU was maxed out during the transfer. (In my testing, I was
able to max out a 7 Mbps cable modem using the
Cisco VPN Client connected
to the same endpoint, so the …
Posted on in Networking
The IEEE802.16 standard defines five Quality of Service (QoS) classes.
UGS was designed to accommodate services that create fixed-size data packets on a regular basis. This class offers grants on a periodic basis and removes the need for subscriber unit access requests. This QoS class …
