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COS 338 Day 7 COS 338 Day 7

DAY 7 Agenda l Questions? l Assignment 2 Corrected l l 1 A, 1 DAY 7 Agenda l Questions? l Assignment 2 Corrected l l 1 A, 1 C, 1 D, 1 F and 2 non-submits Lab 3 graded l 5 A’s and 1 B l Lab 2 Write Due Oct 3 l Capstone Proposal must be approved by OCT 6 l l Submit at any time (prior to Oct 6) using format specified in Capstone guidelines Today is Lecture on Ethernet LANS and Exam #1 l Chap 1 -3, open book, open notes, 60 min, 25 M/c questions 2

Ethernet LANs Chapter 4 Panko’s Business Data Networks and Telecommunications, 5 th edition Copyright Ethernet LANs Chapter 4 Panko’s Business Data Networks and Telecommunications, 5 th edition Copyright 2005 Prentice-Hall

Perspective l Ethernet is the dominant LAN technology l You need to know it Perspective l Ethernet is the dominant LAN technology l You need to know it well l Basic Ethernet switching is very simple l However, large Ethernet networks require more advanced knowledge 4

Ethernet History l Developed at Xerox Palo Alto Research Center in the 1970 s Ethernet History l Developed at Xerox Palo Alto Research Center in the 1970 s l l l After a trip to the University of Hawaii’s Alohanet project Bob Metcalf (from Maine) Taken over by the IEEE l 802 LAN/MAN Standards Committee is in charge of LAN Standards l 802. 3 Working Group develops Ethernet standards l Other working groups create other standards 5

Ethernet Standards are OSI Standards l Ethernet standards are LAN standards l LANs (and Ethernet Standards are OSI Standards l Ethernet standards are LAN standards l LANs (and WANs) are single networks l Single networks are based on Layer 1 (physical) and Layer 2 (data link) standards l OSI dominates standards at these layers l Ethernet standards are OSI standards l Must be ratified by ISO, but this is a mere formality 6

Ethernet Physical Layer Standards Ethernet Physical Layer Standards

Figure 4 -1: Ethernet Physical Layer Standards Physical Layer Standard Speed Maximum Medium Run Figure 4 -1: Ethernet Physical Layer Standards Physical Layer Standard Speed Maximum Medium Run Length UTP 10 Base-T 100 Base-TX 1000 Base-T 10 Mbps* 100 meters 4 -pair Category 3 or better 100 Mbps 100 meters 4 -pair Category 5 or better 1, 000 Mbps 100 meters 4 -pair Category 5 or better *With autosensing, 100 Base-TX NICs and switches will slow to 10 Mbps for 10 Base-T devices. Often called 10/100 Ethernet 8

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard Speed Maximum Medium Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard Speed Maximum Medium Run Length Optical Fiber 100 Base-FX 100 Mbps 2 km 62. 5/125 multimode, 1300 nm, switch 9

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard Speed Maximum Medium Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard Speed Maximum Medium Run Length 1000 Base-SX 1 Gbps 220 m 62. 5/125 micron multimode, 850 nm, 160 MHz-km modal bandwidth 1000 Base-SX 1 Gbps 275 m 62. 5/125 micron multimode, 850 nm, 200 MHz-km 500 m 50/125 micron multimode, 850 nm, 400 MHz-km 1000 Base-SX 1 Gbps 550 m 50/125 micron multimode, 850 nm; 500 MHz-km Gigabit Ethernet, 850 nm, various core sizes and modal bandwidths 10

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 1000 Base-LX Speed Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 1000 Base-LX Speed Maximum Medium Run Length 1 Gbps 550 m 62. 5/125 micron multimode, 1310 nm 1000 Base-LX 1 Gbps 5 km 9/125 micron single mode, 1310 nm Gigabit Ethernet, 1300 nm, multimode versus single mode 11

Perspective l Access links to client stations today are dominated by 100 Base-TX l Perspective l Access links to client stations today are dominated by 100 Base-TX l Trunk links today are dominated by 1000 Base. SX l Short trunk links, however, use UTP l Longer and faster trunk links use other fiber standards 12

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 10 GBase-SR/SW 10 Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 10 GBase-SR/SW 10 GBase-LX 4 Speed 10 Gbps Maximum Medium Run Length 65 m 62. 5/125 micron multimode, 850 nm 62. 5/125 micron 300 m multimode, 1300 nm, WDM with 4 lambdas 10 Gbps Ethernet, multimode S = 850 nm, L = 1300 nm R=LAN, W=WAN 13

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 10 GBase-LR/LW Speed Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 10 GBase-LR/LW Speed Maximum Medium Run Length 10 Gbps 10 km 9/125 micron single mode, 1300 nm. 10 GBase-ER/EW 10 Gbps 40 km 9/125 micron single mode, 1550 nm. 10 Gbps Ethernet, for wide area networks L = 1300 nm, E = 1550 nm R = LAN, W = WAN 14

Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 40 Gbps Ethernet Figure 4 -1: Ethernet Physical Layer Standards, Continued Physical Layer Standard 40 Gbps Ethernet Speed 40 Gbps Maximum Medium Run Length Under 9/125 micron Development single mode. 15

Figure 4 -1: Ethernet Physical Layer Standards, Continued l Notes: l For 10 GBase-x, Figure 4 -1: Ethernet Physical Layer Standards, Continued l Notes: l For 10 GBase-x, LAN versions (R) transmit at 10 Gbps. WAN versions (W) transmit at 9. 95328 Gbps for carriage over SONET/SDH links (see Chapter 6) l The 40 Gbps Ethernet standards are still under preliminary development 16

Figure 4 -2: Baseband Versus Broadband Transmission Baseband Transmission Signal Source Transmitted Signal (Same) Figure 4 -2: Baseband Versus Broadband Transmission Baseband Transmission Signal Source Transmitted Signal (Same) Transmission Medium Signal is injected directly into the transmission medium (wire, optical fiber) Inexpensive, so dominates wired LAN transmission technology 17

Figure 4 -2: Baseband Versus Broadband Transmission, Continued Broadband Transmission Modulated Signal Source Radio Figure 4 -2: Baseband Versus Broadband Transmission, Continued Broadband Transmission Modulated Signal Source Radio Tuner Radio Channel Signal is first modulated to a higher frequency, then sent in a radio channel Expensive but needed for radio-based networks 18

Figure 4 -3: Link Aggregation (Trunking) 100 Base-TX Switch Two links provide 200 Mbps Figure 4 -3: Link Aggregation (Trunking) 100 Base-TX Switch Two links provide 200 Mbps of trunk capacity between the switches UTP Cord No need to buy a more expensive Gigabit Ethernet port Switch must support link aggregation (trunking) 100 Base-TX Switch 19

Figure 4 -4: Data Link Using Multiple Switches Original Signal Received Regenerated Signal Switches Figure 4 -4: Data Link Using Multiple Switches Original Signal Received Regenerated Signal Switches regenerate signals before sending them out; this removes errors 20

Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Received Signal Regenerated Signal Thanks to regeneration, signals can travel far across a series of switches 21

Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Received Signal Regenerated Signal UTP 100 Base-TX (100 m maximum) Physical Link 62. 5/125 Multimode Fiber UTP 1000 Base-SX (220 m maximum) Physical Link 100 Base-TX (100 m maximum) Physical Link Each transmission line along the way has a distance limit. 22

Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Figure 4 -4: Data Link Using Multiple Switches, Continued Received Original Received Regenerated Signal Received Signal Regenerated Signal UTP 100 Base-TX (100 m maximum) Physical Link 62. 5/125 Multimode Fiber UTP 1000 Base-SX (220 m maximum) Physical Link 100 Base-TX (100 m maximum) Physical Link Data Link Does Not Have a Maximum Distance (420 m distance spanned in this example) 23

Ethernet Data Link (MAC) Layer Standards 802 Layering Frame Syntax Switch Operation Ethernet Data Link (MAC) Layer Standards 802 Layering Frame Syntax Switch Operation

Figure 4 -5: Layering in 802 Networks Internet Layer Data Link Layer Logical Link Figure 4 -5: Layering in 802 Networks Internet Layer Data Link Layer Logical Link Control Layer Governs aspects of the communication needed by all LANs, e. g. , error correction. These functions not used in practice. Media Access Control Layer Governs aspects of the communication specific to a particular LAN technology, e. g. , Ethernet, 802. 11 wireless LANs, etc. Physical Layer 25

Figure 4 -5: Layering in 802 Networks, Continued Internet Layer Data Link Layer TCP/IP Figure 4 -5: Layering in 802 Networks, Continued Internet Layer Data Link Layer TCP/IP Internet Layer Standards (IP, ARP, etc. ) Logical Link Control Layer Media Access Control Layer Physical Layer Other Internet Layer Standards (IPX, etc. ) 802. 2 Ethernet 802. 3 MAC Layer Standard Other MAC Standards (802. 5, 802. 11, etc. ) 1000 Base. SX Other Physical Layer Standards (802. 11, etc. ) 10 Base-T … 26

Figure 4 -6: The Ethernet Frame Field Preamble (7 Octets) 1010 … Start of Figure 4 -6: The Ethernet Frame Field Preamble (7 Octets) 1010 … Start of Frame Delimiter (1 Octet) 10101011 Destination MAC Address (48 bits) Source MAC Address (48 bits) Computers use raw 48 -bit MAC addresses; Humans use Hexadecimal notation (A 1 -23 -9 C-AB-33 -53), Which is discussed Later. 27

Figure 4 -6: The Ethernet Frame, Continued Field Length (2 Octets) Data Field (Variable Figure 4 -6: The Ethernet Frame, Continued Field Length (2 Octets) Data Field (Variable Length) LLC Subheader (Usually 8 Octets) Packet (Variable Length) PAD Field Frame Check Sequence (4 Octets) Added if data field is less than 46 octets; length set to make data field plus PAD field 46 octets; Not added if data field is greater than 46 octets long. If an error is found, the frame is discarded. 28

Figure 4 -7: Hexadecimal Notation 4 Bits (Base 2)* Decimal (Base 10) Hexadecimal (Base Figure 4 -7: Hexadecimal Notation 4 Bits (Base 2)* Decimal (Base 10) Hexadecimal (Base 16) 0000 0001 0010 0 1 2 0 hex 1 hex 2 hex 0011 0100 0101 0110 0111 3 4 5 6 7 3 hex 4 hex 5 hex 6 hex 7 hex Begin Counting at Zero * 2^4=16 combinations 29

Figure 4 -7: Hexadecimal Notation, Continued 4 Bits (Base 2) Decimal (Base 10) Hexadecimal Figure 4 -7: Hexadecimal Notation, Continued 4 Bits (Base 2) Decimal (Base 10) Hexadecimal (Base 16) 1000 1001 8 9 8 hex 9 hex 1010 1011 1100 1101 1110 1111 10 11 12 13 14 15 A hex B hex C hex D hex E hex F hex After 9, Count A Through F 30

Figure 4 -7: Hexadecimal Notation, Continued l Converting 48 -Bit MAC Addresses to Hex Figure 4 -7: Hexadecimal Notation, Continued l Converting 48 -Bit MAC Addresses to Hex l Start with the 48 -bit MAC Address l 101000011011 … l Break the MAC address into twelve 4 -bit “nibbles” l 1010 0001 1101 … l Convert each nibble to a hex symbol l A 1 D D l Write the hex symbols in pairs (each pair is an octet) and put a dash between each pair l A 1 -BB-3 C-D 7 -23 -FF 31