9-1©2005 Raj JainCSE473sWashington University in St. LouisHighHigh--Speed LANsSpeed LANsPart IIPart IIRaj Jain Washington UniversitySaint Louis, MO [email protected] slides are available on-line at:http://www.cse.wustl.edu/~jain/cse473-05/9-2©2005 Raj JainCSE473sWashington University in St. LouisOverviewOverviewq Ethernet Frame Formatq Gigabit Ethernetq 10G Ethernetq Token Ringq New Coding Schemes: 4b/5b-NRZI (FDDI), MLT-3 (100BASE-TX), 8b6t (100BASE-T4), 8b10b (Token Ring)9-3©2005 Raj JainCSE473sWashington University in St. LouisIEEE 802.3 Frame FormatIEEE 802.3 Frame Formatq Preamble: 7 bytes of 0101 0101q Start of Frame: 1010 1011q LLC Header: Indicates higher layerq Protocol Type: 2048 or higherLength: 64 through 2047q Padding: Min frame size 64 bytes (DA thru FCS)Maximum Frame size = 1518 bytesq No End of Frame delimiterPre-ambleStart of FrameDest AdrSource AdrLength/Prot TypeLLC headerPadInfoFCS56b 8b 48b 48b 16b 32b9-4©2005 Raj JainCSE473sWashington University in St. LouisEthernet: 1G vs 10G DesignsEthernet: 1G vs 10G Designs1G Ethernetq 1000 / 800 / 622 MbpsSingle data rateq LAN distances onlyq No Full-duplex only ⇒ Shared Modeq Changes to CSMA/CD10G Ethernet! 10.0/9.5 GbpsBoth rates.! LAN and MAN distances! Full-duplex only ⇒ No Shared Mode! No CSMA/CD protocol⇒ No distance limit due to MAC⇒ Ethernet End-to-End9-5©2005 Raj JainCSE473sWashington University in St. LouisGigabit Ethernet PHYsGigabit Ethernet PHYs9-6©2005 Raj JainCSE473sWashington University in St. Louis10Gbps Ethernet PHYs10Gbps Ethernet PHYs9-7©2005 Raj JainCSE473sWashington University in St. Louis10 GbE PMD Types10 GbE PMD Typesq S = Short Wave, L=Long Wave, E=Extra Long Waveq R = Regular reach (64b/66b), W=WAN (64b/66b + SONET Encapsulation), X = 8b/10b ! 4 = 4 λ’sPMD Description MMF SMF10GBASE-R:10GBASE-SR 850nm Serial LAN 300 m N/A10GBASE-LR 1310nm Serial LAN N/A 10 km10GBASE-ER 1550nm Serial LAN N/A 40 km10GBASE-X:10GBASE-LX4 1310nm WWDM LAN 300 m 10 km10GBASE-W:10GBASE-SW 850nm Serial WAN 300 m N/A10GBASE-LW 1310nm Serial WAN N/A 10 km10GBASE-EW 1550nm Serial WAN N/A 40 km10GBASE-LW4 1310nm WWDM WAN 300 m 10 km9-8©2005 Raj JainCSE473sWashington University in St. LouisToken Ring (IEEE 802.5)Token Ring (IEEE 802.5)q Developed from IBM's commercial token ringq Each repeater connects to two others via unidirectional transmission links. Single closed pathq Data transferred bit by bit from one repeater to the nextq Packet removed by transmitter after one trip around the ring9-9©2005 Raj JainCSE473sWashington University in St. Louis802.5802.5MAC ProtocolMAC Protocolq Small frame (token) circulates when idleq Station waits for tokenq Changes one bit in token to make it Start of Frame (SOF) Append rest of data frameq Frame makes round trip and then removed by transmitting stationq Station then inserts new token when transmission has finished and leading edge of returning frame arrivesq Delayed token release vs Immediate token release Under light loads, some inefficiencyq At 100 Mbps and up, only point-to-point operation using switches ⇒ No tokens = Switched Mode = Dedicated Token Ring (DTR)9-10©2005 Raj JainCSE473sWashington University in St. LouisToken Ring OperationToken Ring Operation9-11©2005 Raj JainCSE473sWashington University in St. LouisIEEE 802.5 PHYsIEEE 802.5 PHYsDTRDTRDTRTP or DTRTP or DTRAccessControl18,200 B18,200 B18,200 B18,200 B4550 BMax Frame 8b/10b4b5b-NRZIMLT-3Diff. Manches.Diff. Manches.SignalingFiberFiberUTP or STPUTP, STP, FiberUTP, STP, FiberTrans.Medium1 Gbps100 Mbps100 Mbps16 Mbps4 MbpsDataRate9-12©2005 Raj JainCSE473sWashington University in St. Louist=1t=1+aToken Ring PerformanceToken Ring Performanceq a>1, token is released at t0+a, reaches next station at t0+a+a/N, U=1/(a+a/N)9-13©2005 Raj JainCSE473sWashington University in St. LouisPerformance (Continued)Performance (Continued)q a<1, Token is released at t0+1, U=1/(1+a/N)t=0t=at=1+a9-14©2005 Raj JainCSE473sWashington University in St. LouisLower aNPerformance (continued)Performance (continued)9-16©2005 Raj JainCSE473sWashington University in St. Louis4b/5b4b/5b--NRZINRZIq NRZI:+ Differential ⇒ Polarity mix up is not an issue− No transitions for a string of all zeros− No line state or control symbols− No error detectionq Manchester encoding used in 10 Mbps Ethernet results in 200 MBaud at 100 Mbpsq 4b/5b is used to fix the deficiencies of NRZI0 0 1 0 1 1 0 1 0 0 0 19-17©2005 Raj JainCSE473sWashington University in St. Louis4b/5b Coding4b/5b Codingq 4b/5b: 5 bits are transmitted for every 4 bits of dataq 16 of 32 possible combinations are used for dataq The data symbols have zero dc balance and good transition density (No more 3 zeros in a row)q Six of the remaining combinations are used for control:: Idle: 11111: Start of Stream: 11000-10001: End of Stream: 01101-00111: Transmit error: 00100q 10 Symbols with poor transition density or DC imbalance are not usedq Selected for 100 Mbps Fiber optic LAN: Fiber Distributed Data Interface (FDDI), 100BASE-FXq 100 Mbps data rate ⇒ 125 MBaud signal9-18©2005 Raj JainCSE473sWashington University in St. Louis4b/5b Coding (Cont)4b/5b Coding (Cont)9-19©2005 Raj JainCSE473sWashington University in St. LouisMLTMLT--33q 4b/5b-NRZI produces 62.5 MHz signal (when the line is idle) Too high for UTPq MLT-3: Replace NRZI with a 3-level coding similar to AMIq Zero ⇒ No transitionq One ⇒ Transition to next level in the same direction0 0 1 0 1 1 0 1 1 1 1 11 Cycle1 Cycle9-20©2005 Raj JainCSE473sWashington University in St. LouisMLTMLT--3 State Transition Diagram3 State Transition Diagramq Maximum Frequency is 31.25 MHz9-21©2005 Raj JainCSE473sWashington University in St. Louis8b6t8b6tq Ternary symbols = 3 levels + - 0q 8b are coded as 6 ternary-symbolsq 6 Ternary symbols = 36= 729 possible combinations256 combinations are used for dataq In 100BASE-T4, three wire pairs are usedTwo symbols are transmitted on each pairq Baud Rate = 100 Mbps ÷ 8 bits × 6 Baud ÷ 3 = 25 MBaud per pair9-22©2005 Raj JainCSE473sWashington University in St. Louis8b6t Code Table (Partial)8b6t Code Table (Partial)9-23©2005 Raj JainCSE473sWashington University in St. Louis8b/10b8b/10bq Used in Fiber Channel (100 MB/s interconnect used in storage) and in Gigabit Ethernetq 8 data bits are coded as 10 signaling bitsq First 5 data bits are coded as 6 signaling bitsq Last 3 data bits are coded as 4 signaling bitsq Disparity Control: q Too many