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IEEE 802.3

The first version was an attempt to standardize although there was an ethernet header field is defined differently, then there have been extensions to the standard that covered successive enlargements speed (Fast Ethernet, Gigabit Ethernet and 10 Gigabit), network virtual hubs, switches and various types of media, both fiber optic and copper cables (both coaxial and twisted pair).

The standards of this group do not necessarily reflect what is used in practice, although unlike other groups this is usually close to reality.

IEEE 802.1D

802.1D is the IEEE standard for MAC bridges (bridges MAC), which includes bridging (packet forwarding technique used by switches), the protocol Spaning Tree and operation of 802.11 networks, among others.

It also prevents loops that are formed when switches or bridges are interconnected through several rutas.el algorithm achieved by exchanging BPDU messages with other switches to detect loops and then removes the loop by the closure of bridge selected interfaces. This algorithm guarantees that there is one and only one active path between two network devices.

VLANs (virtual LANs) are not part of 802.1D, but IEEE_802.1Q.

History:

• 1990 - Original Publication (802.1D-1990), based on the ISO / IEC 10038.
• 1998 - Revised version (802.1D-1998), incorporating the extensions 802.1p, P802.12e, 802.1j 802.6k.
• 2004 - Revised version (802.1D-2004), incorporating the extensions 802.1ty 802.1w, which was published separately in 2001, removed the original protocol Spanning tree and instead joined the Rapid Spanning Tree Protocol (RSTP) for 802.1w.

IEEE 802.1Q

The IEEE 802.1Q protocol was a project of the Working Group 802 of the IEEE to develop a mechanism to allow multiple networks to transparently share the same physical medium, without interference problems between them (Trunking). It is also the name of the current standard set in this project and is used to define the encapsulation protocol used to implement this mechanism in Ethernet networks.

Format of the plot

802.1Q does not actually encapsulate the original frame but adds 4 bytes to the original Ethernet header. EtherType field value is changed to 0 × 8100 to mark the change in the format of the plot.

Because the change of the header changes the frame, 802.1Q forces a recalculation of the field "FCS".

Native VLAN

Section 9 of the standard defines the encapsulation protocol used to multiplex multiple VLANs across a single link, and introduces the concept of native VLAN. The plots belonging to the native VLAN is not tagged with the VLAN ID when sent over the trunk. And on the other hand, if a frame arrives port untagged, the plot is considered to belong to the native VLAN of that port. This funcionamiennto mode was implemented to ensure interoperability with older devices that do not understand 802.1Q.

The native VLAN is the VLAN to which he belonged on a switch port before being configured as a trunk. You can only have a native VLAN per port.

To establish a trunking 802.1qa both sides should have the same native VLAN as the encapsulation has not yet been established and the two switches must be talking about a link without encapsulation (using the native VLAN) to agree on these parameters. In teams of Cisco Systems default native VLAN is VLAN 1. VLAN 1 For further data, it sends information about PAgP, CDP, VTP.

During the design is recommended

• The native VLAN should not be the management.
• Change the native VLAN from 1 to any other as a security measure.
• All switches in the same native VLAN.
• Users and servers in their respective VLANs.
• Traffic between switches must be the only one not encapsulate in trunk links. The other traffic, including the management VLAN must be encapsulated by the trunks. If we are encapsulating anyone can connect a computer that does not speak 802.1q (switches and hubs) and work without our control.

IEEE 802.1p

IEEE 802.1p standard that provides a traffic prioritization and dynamic multicast filtering. Essentially, it provides a mechanism for implementing Quality of Service (QoS) at the MAC (Media Access Control).

There are 8 different classes of service, expressed in terms of 3-bit user priority field (user_priority) IEEE_802.1Q the header added to the plot, assigning each packet a priority level between 0 and 7. Although a prioritization method used in LAN environments rather, has several disadvantages, such as the requirement of an additional label 4 bytes (as defined in standard IEEE802.1Q). Addition can only be supported on a LAN, as the 802.1Q tags are removed when the packets pass through a router.

It is defined as how to handle the traffic that is assigned a particular class or priority, leaving freedom to the implementations. IEEE, however, has made extensive recommendations.

802.1p is integrated into IEEE_802.1D and 802.1Q standards.

IEEE 802.1X

The IEEE 802.1X is an IEEE standard for network admission control based on ports. Group is part of IEEE 802 (IEEE 802.1). Enables authentication of devices connected to a LAN port, establishing a point to point connection or preventing access to that port if authentication fails. It is used in certain closed wireless access points and is based on the Extensible Authentication Protocol (EAP-RFC 2284). The RFC 2284 has been deprecated in favor of RFC 3748.

802.1X is available in certain network switches and can be configured to authenticate nodes that are equipped with software supplicant. This eliminates unauthorized access to the network at the level of the data link layer.

Some vendors are implementing 802.1X wireless access points that can be used in certain situations in which the access point needs to be operated as a closed access point, correcting security flaws in WEP. This authentication is normally performed by a third party such as a RADIUS server. This allows only authentication of the client or, more appropriately, strong mutual authentication using protocols such as EAP-TLS.

IEEE 802.11

The IEEE 802.11 or Wi-Fi IEEE that defines the use of the two lower levels of the OSI (physical layer and data link), specifying its rules of operation in a WLAN. The 802.x protocols define the technology branch of local area networks and metropolitan area networks (MAN).

Today most products are of the specification by the g, but has already completed the first draft of the 802.11n standard that raises the theoretical limit to 600 Mbps There are already several products that meet a first draft of N standard with up to 300 Mbps (80-100 stable).

802.11n makes use of both bands, 2.4 GHz and 5 GHz networks operating under the 802.11b and 802.11g standards may suffer interference from microwave ovens, cordless phones and other equipment using the same band 2 , 4 Ghz.

However, the massification of 802.11n technology, which seems to be on the way, also provide a gradual saturation in the spectrum of "free use" in the 5 GHz band.

Ultimately based services at 5.4 GHz, such as "WiMax, Unlicensed" or Pre-Wimax, could be seriously affected, especially in cities where overcrowding is most likely wireless users.

This has already occurred between the years 2004-2005, also called "pre-wimax" working in the 2.4 GHz frequency and caused 100% of the links installed in the cities they saw severely affected by interference from the wifi.

It all started when DSL operators, I'll give wifi router 2.4GHz (802.11bg), this mass of users in the 2.4 GHz band caused the failure of the operation of a distance links (greater than 100 meters), because of the saturation spectrum.

It could be a strategy of the operations themselves, to eliminate competition in services that do not have licenses to use radio spectrum, but could also harm other initiatives that use free bands as a means of communication for urban networking.

IEEE 802.11 legacy

The original version of IEEE 802.11 standard published in 1997 specifies two theoretical transmission speeds of 1 and 2 megabits per second (Mbit / s) transmitted by infrared signals (IR). IR remains part of the standard, although no actual implementations.

The original standard also defines the CSMA / CA (Multiple Carrier Detect access by avoiding collisions) as the access method. An important part of the theoretical transmission speed is used in this encoding needs to improve the transmission quality under different environmental conditions, which resulted in difficulties for interoperability between equipment from different brands. These and other weaknesses were corrected in the 802.11b standard, which was the first of this family to reach wide acceptance among consumers.

IEEE 802.11a

In 1997 the IEEE (Institute of Electrical and Electronics Engineers) created the 802.11 standard with transmission speeds of 2Mbps.

In 1999 the IEEE approved two standards: the 802.11a and 802.11b.

In 2001 he made his appearance on the market 802.11a products.

The revision to the original standard 802.11a was ratified in 1999. The 802.11a standard uses the same basic set of protocols that the original standard, operates in the 5 GHz band and uses 52 subcarriers orthogonal frequency-division multiplexing (OFDM) with a maximum speed of 108 Mbit / s, making it practical standard for wireless networks with actual speeds of approximately 20 Mbit / s. The data rate is reduced to 48, 36, 24, 18, 12, 9 and 6 Mbit / s if necessary. 802.11a has 12 non-overlapping channels, 8 for wireless networking and 4 for point to point. Can not interoperate with 802.11b standard equipment unless equipment is available that implement both standards.

Since the 2.4 GHz band is of great use (it is the same band used by cordless phones and microwave ovens, among other devices), the use of 5 GHz band is an advantage of the 802.11a standard, since it have less interference. However, the use of this band also has its disadvantages, since it restricts the use of 802.11a equipment online only points of view, which is necessary to install a greater number of access points; This also means teams working with this standard can not penetrate as far as the 802.11b standard because its waves are more easily absorbed.

IEEE 802.11b

The review original 802.11b standard was ratified in 1999. 802.11b has a maximum transmission rate of 11 Mbit / s using the same access method CSMA / CA defined in the original standard. The 802.11b standard operates in the 2.4 GHz band due to the space occupied by the codification of CSMA / CA, in practice, the transmission speed of this standard is about 5.9 Mbit / s over TCP and 7.1 Mbit / s over UDP.

But it also uses a spread spectrum technique based on DSSS, 802.11b extension actually introduces CCK (Complementary Code Keying) to reach speeds of 5.5 and 11 Mbps (physical rate bit). The standard also supports the use of PBCC (Packet Binary Convolutional Coding) as optional. 802.11b devices must maintain compatibility with previous DSSS equipment specified in the original IEEE 802.11 standard bit rates of 1 and 2 Mbps

IEEE 802.11c

It is less used than the first two, but by implementing this protocol reflects. The protocol 'c' is used for communication of two different networks or different types, such as connecting two separate buildings, both with each other, and connect two different types of networks through a wireless connection. The protocol 'c' is used daily because of the cost of long distance optical fiber installation, although more reliable, more expensive both in money market instruments and in time of installation.

IEEE 802.11d

It complements the 802.11 standard that is designed to enable international use of local 802.11 networks. It allows different devices to exchange information in the frequency ranges depending on what is allowed in the country of origin of the device.

IEEE 802.11e

With the 802.11 standard, IEEE 802.11 technology supports real-time traffic in all types of environments and situations. Real-time applications are a reality for the guaranteed Quality of Service (QoS) provided by the 802.11e. The aim of the new 802.11e standard is to introduce new mechanisms at the MAC layer to support services requiring Quality of Service guarantees. To achieve its objective IEEE 802.11e introduces a new element called Hybrid Coordination Function (HCF) with two types of access:

• (EDCA) and Enhanced Distributed Channel Access
• (HCCA) Controlled Access.

IEEE 802.11f

It is a recommendation for the provision of access points that allows products to be more compatible. Use the IAPP protocol that allows a roaming user clearly changed from an access point to another while on the move no matter what brand of access points used in the network infrastructure. Also this property is known simply as roaming.

IEEE 802.11g

In June 2003, was ratified a third modulation standard: 802.11g. That is the evolution of the 802.11b standard, this uses the 2.4 GHz band (like the standard 802.11b) but operates at a theoretical maximum speed of 54 Mbit / s, which on average is 22.0 Mbit / s real speed transfer, similar to the 802.11a standard. It is compatible with the standard by using the same frequencies. Much of the standard design process it took to reconcile the two standards. However, under the standard g networks the presence of nodes under the standard b significantly reduces the transmission rate.

The teams working under the 802.11g standard came to market very quickly, even before ratification was given approx. June 20, 2003. This was due in part to team-building under this new standard could be adapted and designed for the standard b.

Currently sold equipment to this specification, with outputs of up to half a watt, which allows communications up to 50 km with appropriate dishes. and i-MOX technology will reach several kilometers.

IEEE 802.11h

The 802.11h specification is a modification of the 802.11 WLAN standard developed by the working group 11 of the standards committee LAN / MAN of the IEEE (IEEE 802) and which was released in October 2003. 802.11h attempts to resolve problems arising from the coexistence of 802.11 networks with radar and satellite systems

802.11h is developing the recommendations made by the ITU who were motivated mainly because of the requirements that the European Radiocommunications Office (ERO) considered desirable to minimize the impact of opening the 5 GHz band, usually used by military systems, ISM applications (ECC / DEC / (04) 08).

To meet these requirements, 802.11h provides 802.11a networks the ability to manage both the frequency dynamically, such as power transmission.

Dynamic Frequency Selection and Transmitter Power Control

DFS (Dynamic Frequency Selection) is a required functionality for WLANs operating in the 5GHz band in order to avoid co-channel interference with radar systems and to ensure uniform use of the available channels.

TPC (Transmitter Power Control) functionality is required for WLANs operating in the 5GHz band to ensure that it satisfies the constraints that can be transmitted power for different channels in a given region, so as to minimize interference with systems satellite.

IEEE 802.11i

It is aimed at beating the current vulnerability to security authentication protocols and encryption. The standard encompasses 802.1X, TKIP (Protocol integrated key - Insurance - Temporary) and AES (Advanced Encryption Standard). It is implemented in WPA2.

IEEE 802.11j

Japan is to regulate what the 802.11h is to European regulation.

IEEE 802.11k

Allows switches and wireless access points to calculate and assess the radio resources of WLAN clients, improving their management. It is designed to be implemented in software, to support the WLAN equipment only needs to be updated. And, of course, for the standard to be effective, must be compatible both customers (adapters and WLAN cards) and infrastructure (access points and WLAN switches).

IEEE 802.11n

In January 2004, the IEEE announced the formation of a working group 802.11 (Tgn) to develop a new revision of the 802.11 standard. The actual transmission speeds could reach 600 Mbps (which means that the theoretical transmission speeds would be even higher) and should be up to 10 times faster than a network under 802.11a and 802.11g standards, and about 40 times faster than a network under the 802.11b standard. It is also hoped that the scope of operation of the networks is greater with this new standard through the MIMO Multiple Input - Multiple Output, which can use different channels at once to send and receive data by incorporating multiple antennas (3 ). There are also alternative proposals that may be considered and it is expected that the standard that should be completed by end 2006, is implemented by 2008. In early 2007 approved the second draft standard. Earlier devices had already developed the protocol and offered it as an unofficial standard (with the promise of upgrades to meet the standard when the final was implanted). Has suffered a series of delays and the latest takes him to November 2009. Having adopted in January 2009 that the project 7.0 and is on track to meet target dates señaladas.Status of Project IEEE 802.11n.

Unlike other versions of Wi-Fi, 802.11n can operate in two frequency bands: 2.4 GHz (using the 802.11b and 802.11g) and 5GHz (which uses 802.11a). As a result, 802.11n is compatible with all devices based on earlier editions of Wi-Fi. It is also useful to work in the 5 GHz band because it is less congested and 802.11n achieves higher performance.

IEEE 802.11p

This standard operates in the frequency spectrum of 5.9 GHz, particularly suitable for automobiles. It will be the basis of the Dedicated Short Range Communication (DSRC) in North America. DSRC technology enables data exchange between vehicles and between vehicles and roadside infrastructure.

IEEE 802.11r

Also known as Fast Basic Service Set Transition, and its main characteristic is to allow the network to establish the security protocols that identify a device on the new access point before you leave today and come over to him. This feature, which seems obvious once stated, indispensable in a wireless data system, allows the transition between nodes take less than 50 milliseconds. A time lapse of this magnitude is short enough to communicate via VoIP without any noticeable cuts.

IEEE 802.11s

Define interoperability protocols manufacturers regarding Mesh (those networks that mix the two topologies of wireless networks, Ad-hoc topology and topology infrastructure.). It is well known that there is no standard, and that is why each manufacturer has its own mechanisms for grid generation.

IEEE 802.11w

Not yet completed. TWG is working on improving access control layer of IEEE 802.11 medium to increase the security of authentication protocols and encryption. The wireless LAN system sends information in unprotected plots, which makes them vulnerable. This standard may protect networks against disruption caused by malicious systems that create disassociated requests that appear to be sent by the valid team. It attempts to extend the protection provided by the 802.11i standard beyond data to management frames, responsible for the main components of a network. These extensions will have interactions with 802.11re IEEE IEEE 802.11u.

Proprietary protocol

IEEE 802.11g +

Today, 802.11g Turbo mode, with a band of 2.4 GHz, achieves a transfer rate of 108 Mbps This is provided by the Atheros chipset.

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