Module 7 Chapter 6 Ethernet Technologies

10-Mbps Ethernet Legacy Ethernet –10BASE5, 10BASE2, and 10BASE-T Four common features of Legacy Ethernet –Timing parameters –Frame format –Transmission process –Basic design rule

10-Mbps Ethernet 10BASE5 Single thick coaxial cable busCable is large and heavy Primary benefit was length (500m)Only in half-duplex InexpensiveSensitive to signal reflection No configurationNot for new installations Components are difficult to findDifficult to install

10-Mbps Ethernet 10BASE2 Uses half-duplexCompared to 10Base5 Components are difficult to findLow cost No need for hubsSmaller size, lighter weight Not for new installations Greater flexibility Thin net Installation easier

10-Mbps Ethernet 10BASE-T Cheaper and easier to installExtended Star Category 3 Originally half-duplex protocol Category 5 Full-duplex features added later Category 5e New installations Cat5e or better Uses a hub 10 Mbps in half-duplex mode Star topology 20 Mbps in full-duplex mode

Wiring and Architecture rule –No more than five segments –Separated by no more than four repeaters. –No more than three populated segments between any two distant stations Hubs or repeaters merely extend the length of a network segment within a single collision domain Bridges and switches divide a segment into separate collision domains

Manchester Encoding Manchester encoding is used in 10 Mbps systems The direction of the edge transition in the middle of the timing window determines the binary value

100-Mbps Ethernet 100-Mbps Ethernet is also known as Fast Ethernet –100BASE-TX is copper UTP –100BASE-FX is multimode optical fiber Three common characteristics: –Timing parameters –Frame format –Parts of the transmission process

100-Mbps Ethernet Timing parameters –One bit time in 100-Mbps Ethernet is 10nsec Frame format –100-Mbps frame format is the same as the 10- Mbps frame Parts of the transmission process –Two separate encoding steps are used The first part of the encoding uses a technique called 4B/5B The second part of the encoding is the actual line encoding specific to copper or fiber

100-Mbps Ethernet 100BASE-TX uses 4B/5B encoding which is then scrambled Converted to multi-level transmit-3 levels or MLT-3. Half-duplex = 100 Mbps Full-duplex = 200 Mbps

Fast Ethernet Architecture Fast Ethernet links consist of a connection between a station and a hub or switch –Hubs are considered multi-port repeaters –Switches are considered multi-port bridges –These are subject to the 100 m UTP distance limitation

Fast Ethernet Architecture Class I repeater –Any repeater that changes between one Ethernet implementation and another –140 bit-times of latency Class II repeater –92 bit-times latency –Cable between Class II repeaters may not exceed 5 meters

Fast Ethernet Architecture Signaling scheme is inherently full duplex –Half duplex are not uncommon –Half duplex is undesirable Switches have made the 100m limitation less important Workstations are located within 100m of the switch 100 m distance starts over at the switch

1000-Mbps Ethernet 1000-Mbps Ethernet or Gigabit Ethernet Transmission –Fiber and copper media The 1000BASE-X IEEE 802.3z –Specifies 1 Gbps full duplex over optical fiber 1000BASE-TX, 1000BASE-SX, and 1000BASE-LX –Timing parameters 1 nanosecond or 1 billionth of a second bit time. –Frame Format Same format used for 10 and 100-Mbps Ethernet –Transmission Depending on the implementation

1000-Mbps Ethernet 1000BASE-T (IEEE 802.3ab) was developed to provide additional bandwidth for: –Intra-building backbones –Inter-switch links –Server farms –Connections for high-end workstations –Supports both half-duplex and full-duplex Fiber-based Gigabit Ethernet (1000BASE-X) –Uses 8B/10B encoding (similar to 4B/5B) –This is followed by Non-Return to Zero (NRZ) line encoding

1000Base-LX/SX Common to all versions of 1000 Mbps –Timing –Frame format –Transmission NRZ signals are pulsed into the fiber –Short-wavelength (1000BASE-SX ) –Long-wavelength (1000BASE-LX) Media Access Control –Link as point-to-point Separate fibers –Transmitting (Tx) –Receiving (Rx) –Inherently full duplex

Gigabit Ethernet Gigabit Ethernet is the dominant technology for: –Backbone installations, –High-speed cross-connects –General infrastructure

10 Gigabit Ethernet IEEE 802.3ae, governs the 10GbE family Provide increased bandwidth Interoperable with existing infrastructure Implementations being considered : –10GBASE-SR –10GBASE-LX4 –10GBASE-LR and 10GBASE-ER –10GBASE-SW, 10GBASE-LW, and 10GBASE-EW

10 Gigabit Ethernet 10GBASE-SR – –short distances, supports a range between 26 m to 82 m 10GBASE-LX4 – –Uses wide wavelength division multiplexing (WWDM) –240 m to 300 m over multimode fiber –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 –Works with OC-192 synchronous transport module

Future of Ethernet The future of networking media is three-fold : 1.Copper (up to 1000 Mbps, perhaps more) 2.Wireless (approaching 100 Mbps, perhaps more) 3.Optical fiber (currently at 10,000 Mbps and soon to be more) Copper and wireless media have certain physical and practical limitations Limitations on optical fiber are: –Electronics technology emitters and detectors –Fiber manufacturing processes Developments in Ethernet –Heavily weighted towards Laser light sources –Single-mode optical fiber

OK Lab Time. Then……..have a good week !