My Netwok Dictionary

Fast Ethernet links usually consist of a connection between the station and the hub or switch. The multiport repeaters are considered hubs and switches are considered multiport bridges. These are subject to the limitation of 100 m of UTP media.

A Class 1 repeater can enter up to 140 bit times of latency. Any repeater that changes between one Ethernet implementation and another is a Class 1 repeater. A Class II repeater is restricted to minor delays, 92 bit times because it immediately repeats the incoming signal to all other ports without a translation process. To achieve a smaller timing delay, Class II repeaters to be connected to the segment types that use the same signaling technique. Read the rest of this entry »

In the data link layer, the structure of the plot is nearly identical for all speeds of Ethernet from 10 Mbps up to 10000 Mbps. However, the physical layer, almost all versions of Ethernet are substantially different from each other, with each rate a different set of architectural design rules.

In the version of Ethernet developed by DIX before the adoption of the IEEE 802.3 version of Ethernet, the preamble and the Start Frame Delimiter (SFD) were combined in a single field, although the binary pattern was identical. The field is called length/type appeared as only length in earlier versions of IEEE and only as a type in the version of DIX. Read the rest of this entry »

The security of wireless transmissions can be difficult to achieve where there are wireless networks, security is reduced. This has been a problem since the early days of the WLAN. At present, many administrators are not concerned to implement effective security practices.

Several new protocols are emerging and security solutions such as Virtual Private Networks (VPN) and Extensible Authentication Protocol (EAP). In the case of CAS, the access point provides client authentication, but passes the task to a more sophisticated device, possibly a dedicated server, designed for this purpose. With an integrated server, VPN technology creates a tunnel over an existing protocol such as IP. This is a Layer 3 connection, unlike Layer 2 connection between the AP and the sending node. Read the rest of this entry »

Cisco develops several versions of their operating system IOS (Internetwork Operating System) and launches new versions continuously. The IOS provides various functions and also runs on various hardware platforms.

Cisco has established a convention to identify by name the different versions of IOS files.
The IOS naming convention uses several fields. Read the rest of this entry »

IP Address

IP is one of 32-bit binary number that identifies precisely and only the location of each computer on the Internet. The binary numbers of the IP address in decimal numbers expressed in four parts, each of which represents 8 bits of the 32 total.

During your internet connection, your ISP assigns you an IP number. No matter the type of computer you own or what kind of connection you have, if you’re on the Internet, means that the network protocol you use TCP / IP, and connecting your computer has, at that time, a unique IP number. Read the rest of this entry »

In this tutorial the commands to retrieve the password (password recovery) of Cisco routers for the following models are discussed:

Cisco 1000 Series Router
Cisco 1600 Series Router
Cisco 1700 Series Router
Cisco 1800 Series Router
Cisco 2600 Series Router
Cisco 2800 Series Router
Cisco 3600 Series Router
Cisco 3700 Series Router
Cisco 4500 Series Router
Cisco 7200 Series Router
Cisco 7500 Series Router
Cisco 7200 Series Router
Cisco 12000 Series Router
AS5200 Series
AS5300 Series Read the rest of this entry »

Today there are three different versions: RIPv1, RIPv2, and RIPng.

RIPv1: Version 1 RIP routing protocol is “classy”, i.e., does not support subnetting, VLSM or CIDR, has no authentication mechanisms and does not perform updates triggered by events. All these limitations led to the passage of time and changing needs fall into disuse.

RIPv2: Version 2 of RIP routing protocol is “classless”, supports subnetting, VLSM, CIDR, short routes, has mechanisms plain text authentication or MD5 encryption, performs updates triggered by events.

RIPng: version ng of RIP routing protocol is RIP for IPv6 deployments. If you are interested can read the specifications here. Read the rest of this entry »

Configuring a router, at first, seems a complicated task. Over time, learning the commands, functions and setting up, we will realize that it is not at all, quite the opposite, ends up being a simple process, mechanical.

This tutorial only shows the basic configuration of a router, which we always do, regardless of routing protocols or configure services later.

The routers have several modes and sub modes configuration.

User Exec Mode: This mode allows only limited details of the configuration of the router and does not allow any modification of it.

Privileged Exec mode: This mode allows a detailed look at the router settings for diagnosis and testing. It also allows working with router configuration files (Flash - NVRAM).

Global Configuration Mode: This mode allows basic router configuration and allows access to specific configuration sub modes. Read the rest of this entry »