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Sem1 - Module 7 Ethernet Technologies. 802.2 All versions of Ethernet have the same: 1.MAC addressing 2.CSMA/CD 3.Frame format However, other aspects.

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Presentation on theme: "Sem1 - Module 7 Ethernet Technologies. 802.2 All versions of Ethernet have the same: 1.MAC addressing 2.CSMA/CD 3.Frame format However, other aspects."— Presentation transcript:

1 Sem1 - Module 7 Ethernet Technologies

2 802.2 All versions of Ethernet have the same: 1.MAC addressing 2.CSMA/CD 3.Frame format However, other aspects of the MAC sub layer, physical layer, and medium have changed. 10-Mbps and 100-Mbps Ethernet Legacy Ethernet

3 Legacy Ethernet (10BASE2, 10BASE5, 10BASET) Legacy Ethernet has common architectural features: 1.Networks usually contain multiple types of media. 2.The standard ensures that interoperability is maintained. 3.The overall architectural design is of the utmost importance when implementing a mixed-media network. 4.It becomes easier to violate maximum delay limits as the network grows. 5.The timing limits are based on parameters such as: Cable length and its propagation delay Delay of repeaters Delay of transceivers Interframe gap shrinkage Delays within the station

4 Legacy Ethernet (10BASE2, 10BASE5, 10BASET) 10BASE2: Coax cable (called Thinnet) flexible, 185meters max, Small flexible cable Half Duplex only 10BASE2, introduced in 1985. Installation was easier because of its smaller size, lighter weight, and greater flexibility. It still exists in legacy networks. 10BASE5 Coax cable (called Thicknet) flexible, 500 meters max, larger, heavier cable Half Duplex only 10BASE5 is important because it was the first medium used for Ethernet (10BASE5 was part of the original 802.3 standard). The primary benefits of 10BASE5: was length, today it may be found in legacy installations, but would not be recommended for new installations. 10BASE5 systems are inexpensive and require no configuration 10BASET UTP (Cat5e, Cat5, Cat3) flexible, RJ45, Hubs and witches, 100 meters max, small, light most inexpensive cable, easy to install Half or Full Duplex

5 Common Frame Format 10-Mbps Ethernet:

6 802.2 FastEthernet 100-Mbps Ethernet

7 Fast Ethernet: At the time copper-based Fast Ethernet was introduced, a fiber version was also desired. A fiber version could be used for backbone applications, connections between floors and buildings where copper is less desirable in high noise environments. 100BASE-FX was introduced to satisfy this desire. However, 100BASE-FX was never adopted successfully. This was due to the timely introduction of Gigabit Ethernet copper and fiber standards. Gigabit Ethernet standards are now the dominant technology for backbone installations, high-speed cross-connects, and general infrastructure needs.

8 100BASE-FX: Limitations of Fiber Technology: –The following has limited the bandwidth of Fiber: Emitter technology Detector technology The Fiber manufacturing Process

9 Fast Ethernet Architecture: A Class I repeater may introduce up to 140 bit-times of latency. Any repeater that changes between one Ethernet implementation and another is a Class I repeater. A Class II repeater may only introduce a maximum of 92 bit-times latency. Because of the reduced latency it is possible to have two Class II repeaters in series, but only if the cable between them is very short.

10 Gigabit and 10-Gigabit Ethernet: Access: –Point to point –Full Duplex only: Half duplex is only used in 100Base and lower speeds Half duplex reduces distance and adds increased overhead Introduced for fast data transfer: –Backbone connections (inter building) –Interswitch connections (Trunk lines) –Backup applications –Video and other high applications

11 802.2 1 Gb Ethernet 1000 – Mbps (1 Gbps) Ethernet

12 802.2 10 Gb Ethernet 10000 – Mbps (10 Gbps) Ethernet

13 Half Duplex and Full Duplex Half Duplex: –Capability for simultaneous data transmission between a sending station and a receiving station. Full Duplex: –Capability for data transmission in only one direction at a time between a sending station and a receiving station. –No collisions in a switched network 10BASE2, 10BASE5: –Half Duplex only 10Base-T, 100Base-TX, 100BASE-FX : –Operates in Half or Full Duplex. GigaBit Ethernet: –Operates at Full Duplex only

14 1000BASE-SX and LX The NRZ signals are then pulsed into the fiber using either short-wavelength or long-wavelength light sources. The short-wavelength uses an 850 nm laser or LED source in multimode optical fiber (1000BASE-SX). It is the lower-cost of the options but has shorter distances. The long-wavelength 1310 nm laser source uses either single-mode or multimode optical fiber (1000BASE-LX). Laser sources used with single-mode fiber can achieve distances of up to 5000 meters. Because of the length of time to completely turn the LED or laser on and off each time, the light is pulsed using low and high power. A logic zero is represented by low power, and a logic one by high power.

15 All versions of Ethernet have the same: 1.MAC addressing 2.CSMA/CD 3.Frame format However, other aspects of the MAC sublayer, physical layer, and medium have changed. 1000 - Mbps Ethernet: 1000Base-T, 1000Base-SX, 1000Base-LX The differences between standard Ethernet, Fast Ethernet and Gigabit Ethernet occur at the physical layer: Timing: Due to the increased speeds of these newer standards, the shorter duration bit times require special considerations. Since the bits are introduced on the medium for a shorter duration and more often, timing is critical. Transmission: This high-speed transmission requires frequencies closer to copper medium bandwidth limitations.

16 10-Gigabit Ethernet As is typical for new technologies, a variety of implementations are being considered, including: 10GBASE-SR – Intended for short distances over already-installed multimode fiber, supports a range between 26 m to 82 m 10GBASE-LX4 – Uses wavelength division multiplexing (WDM), supports 240 m to 300 m over already-installed multimode fiber and 10 km over single-mode fiber 10GBASE-LR and 10GBASE-ER – Support 10 km and 40 km over single-mode fiber 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW – Known collectively as 10GBASE-W are intended to work with OC-192 synchronous transport module (STM) SONET/SDH WAN equipment.

17 Encoding: Manchester encoding is used by: –10BASE2. –10BASE5 –10BASE-T 4B/5B encoding, which is then scrambled and converted to multi-level transmit-3 levels or MLT-3: –100BASE-TX 8B/10B encoding which is similar to the 4B/5B concept. This is followed by the simple Non-Return to Zero (NRZ) line encoding of light on optical fiber: –Fiber-based Gigabit Ethernet (1000BASE-X) uses encoding with 4D-PAM5 line encoding is used on Cat 5e or better UTP: –1000BASE-T The 8B/ 10B scheme is used for optical fiber and shielded copper media, and the pulse amplitude modulation 5 (PAM5) is used for UTP.

18 Not more than five segments. No more than four repeaters may be connected in series between any two distant stations. No more than three populated segments between any two distant stations. 10BASE#: The 5-4-3 rule. There may be up to 30 stations on any individual 10BASE2 segment. Out of the five consecutive segments in series between any two distant stations, only three may have stations attached.

19 Interconnection of different versions of Ethernet To interconnect Ethernet: –10BaseT –100BaseTX –1000BaseT Use an asymmetric Bridge or Switch

20 End


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