Let's get PHYsical

The switch hacker's guide to Ethernet PHYs and SFPs

Transcript

1. Let’s get PHYsical The Switch Hacker’s Guide to Ethernet PHYs and SFPs
2. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+
3. Ethernet 101
5. MAC 0101010101 PHY
6. Terminology SPEEDBASE-MEDIA 10BASE-T 40GBASE-SR4
7. Unshielded Twisted Pair Media 10BASE-T 100BASE-TX 1000BASE-T 2500BASE-T 5GBASE-T 10GBASE-T
8. Fiber Optic Media 1000BASE-SX 1000BASE-LX 10GBASE-SR 10GBASE-LR 10GBASE-LRM 40GBASE-SR4 40GBASE-LR4 40GBASE-SR-BiDi
9. Shielded Copper Media 10GSFP+Cu 40GBASE-CR4
10. Duplexity
11. Simplex Half-Duplex Full-Duplex
12. Simplex (usually) Half-Duplex Full-Duplex (these days)
13. 1000BASE-T
14. T/F Full-Duplex is optional
15. Auto-Negotiation
16. 10BASE-T Link Integrity Test Pulse
17. Fast Link Pulse Bursts
18. Fast Link Pulse Burst Detail Clock pulses Data pulses
19. Base Page
20. T/F Auto-Negotiation is optional
21. T/F No Auto-Negotiation for fiber
22. Interfaces
24. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+ Media Dependent Interface
25. “MDI”
26. MDI / MDI-X
27. Differential Signaling
28. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+ Media Independent Interface QSGMII XFI XLAUI
30. MII
31. RMII
32. GMII
33. RGMII
34. SGMII
35. QSGMII
36. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+ Internal & External PHYs PHY PHY PHY PHY PHY
37. PHYnally...
38. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+ La raison d’etre
40. Physical Coding Sublayer (PCS)
41. Block Coding Overhead Block Code Overhead Line Rate 100BASE-TX 4B/5B 25% 125 Mbaud 1000BASE-X 8B/10B 25% 1250 Mbaud 10GBASE-R 64B/66B 3.125% 10.3125 Gbaud
42. Physical Medium Attachment sublayer
43. Physical Medium Dependent sublayer
44. PHY management
45. Clause 22
46. Clause 45
47. Registers
48. 1.c848.13 Device Register Bit
49. Pluggables
50. SFP / SFP+
51. XFI / SFI
52. QSFP+
53. XLAUI / XLPPI
55. # i2cget -y 12 0x53 27 w 0x8890 # i2cget -y 13 0x56 27 w 0x8480 Managing the SFP’s Internal PHY
56. Switch / MAC 1G PHY 1G PHY 10G PHY 10G PHY RJ45 SFP RJ45 SFP+ 40G PHY QSFP+ It’s PHYs All the Way Down PHY PHY PHY PHY PHY PHY
57. But wait, that’s not all!
58. PoE
59. EEE
60. Backplane Ethernet
61. 25GBASE-T 40GBASE-T
62. Recommended Reading Ethernet: The Definitive Guide -- Available on Safari Books Online (free for us!) 10GE Pluggable Transceiver Technology -- Great background on SFP+ modules The Packet Sniffer Blog -- Explains 10G Ethernet; interesting article on switch latency 40 Gigabit Ethernet and 100 Gigabit Ethernet Technology Overview -- Introduction to 40G and 100G Ethernet Overview of the XAUI, XLAUI and CAUI -- Explains the 10G, 40G, and 100G media-independent interfaces Demystifying 40 Gigabit Ethernet Physical Layer Interfaces in Data Centers -- Compares XFI/SFI and XLAUI/XLPPI The Network Sherpa -- Blog covering signal equalization, pre-emphasis, differential signalling, ASIC design An introduction to the Auto-Negotiation process -- Expansive coverage of Clause 28 twisted-pair Auto-Negotiation 1000BASE-T SFP Auto-Negotiation -- Detailed study of how Clause 28 and Clause 37 AN are used in 1000BASE-T SFPs
63. Thanks!
64. Back-up
67. Ethernet over Twisted Pair Copper 10BASE-T 802.3i 1990 100 m Cat-3 100BASE-TX 802.3u 1995 100 m Cat-5 1000BASE-T 802.3ab 1999 100 m Cat-5 2.5GBASE-T 802.3bz 2016 100 m Cat-5e 5GBASE-T 802.3bz 2016 100 m Cat-5e 10GBASE-T 802.3an 2006 55 m Cat-6 100 m Cat-6a
68. 1000BASE-SX 802.3z 1998 550 m OM3 1000BASE-LX 802.3z 1998 10 km SMF 10GBASE-SR 802.3ae 2002 300 m OM3 10GBASE-LR 802.3ae 2002 10 km SMF 10GBASE-LRM 802.3aq 2006 220 m MMF 40GBASE-SR4 802.3ba 2010 100 m OM3 4 lanes 40GBASE-LR4 802.3ba 2010 10 km SMF 4 λs 40GBASE-SR-BiDi Cisco 2013 100 m OM3 2 λs Ethernet over Optical Fiber
69. 10GSFP+Cu SFF-8431 2009 7m twinax SFP+ 40GBASE-CR4 802.3ba 2010 7m twinax QSFP+ Ethernet over Shielded Twin-axial Copper
70. 10GBASE-KR 802.3ap 2007 40GBASE-KR4 802.3ba 2010 Backplane Ethernet
72. Media Independent Interface (MII) Connector
73. AUI 10 Mbps 1-bit MII 10/100 Mbps 4-bit GMII 10/100/1000 Mbps 8-bit XGMII 10 Gbps 32-bit XLGMII 40 Gbps 64-bit Media Independent Interfaces MAC PHY
74. SGMII 10/100/1000 Mbps QSGMII 10/100/1000 Mbps x 4 XAUI 10 Gbps USXGMII 100M/1G/2.5G/5G/10Gbps XLAUI 40 Gbps Serial Media Independent Interfaces MAC PHY
75. Clause 28: Parallel Detection If an interface configured for AN receives valid signalling from link partner, it will assume half-duplex at the detected speed. 1000BASE-X does not support parallel detection: if one link partner has AN enabled and the other does not, the link will not come up.
76. SFP Bit Rate Bit rate specified in hundreds of megabit, rounded: 13 == 1300 Mbps =~ 1.250 Gbps == 1000BASE-X 103 == 10300 Mbps =~ 10.3125 Gbps == 10GBASE-R