Transcript
Alien Crosstalk Measurements and Performance Under Different Installation Practices Chris Pagnanelli Solarflare Communications
pagnanelli_5_21_2003_ipcap.pdf
IEEE802.3 Interim May 2003 10GBASE-T
[email protected] 1
Overview • Purpose: Determine the Impact on 10GBASE-T Capacity of Different Installation Practices using Cat5e Models and Preliminary Cat5e Alien Model. • Review of Installation Options and Associated Alien Mitigation • Capacity Calculations • Summary IEEE802.3 Interim May 2003 10GBASE-T
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Installation Practices (Patch Cords) • Patch Cord Configuration Options: – 10GBASE-T Switch Port Interconnect made with Isolated Patch Cords • Isolation achieved through screening or separation
– 10GBASE-T Switch Port Interconnect made with Tightly-Bundled Patch Cords
• Significantly Less Alien Crosstalk from Isolated Patch Cords – Alien Mitigation up to 2.6 dB per 2 meters of Cat5e – Source: Cohen L., “Alien Crosstalk Measurement,” IEEE802.3 10GBASE-T Contribution, Jan. 2003. IEEE802.3 Interim May 2003 10GBASE-T
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Installation Practices (Horizontal Cable) • Horizontal Cable Configuration Options: – 10GBASE-T Cables Arranged in Tightly Bundled Groups • Tie-wraps located at short intervals
– 10GBASE-T Cables Arranged in Loosely Bundled Groups
• Loose Bundling Introduces Significantly Less Alien NEXT – Alien Mitigation up to 6.4 dB on Cat5e – Source: Cohen L., “Alien Crosstalk Measurement,” IEEE802.3 10GBASE-T Contribution, Jan. 2003. IEEE802.3 Interim May 2003 10GBASE-T
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Installation Practices (Patch Panel) • Patch Panel Configuration Options: – 10GBASE-T Traffic Located on Adjacent Patch Panel Ports – 10GBASE-T Traffic Located on Separated Patch Panel Ports
• Significantly Less Alien Crosstalk from Separated Patch Panel Ports – Alien Mitigation up to 6.6 dB on Cat5e – Source: Cohen L., “Alien Crosstalk Measurement,” IEEE802.3 10GBASE-T Contribution, Jan. 2003. IEEE802.3 Interim May 2003 10GBASE-T
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Capacity Calculations • 10GBASE-T Cabling Ad Hoc Channel Models: – Established models for Category 5e Insertion Loss, Return Loss, self NEXT and self FEXT (April 17, 2003). – Preliminary model for Category 5e Alien NEXT with scaling for Different Installation Practices.1
• Background Noise – Upper bound noise level of -150 dBm/Hz appears consistent with actual data center noise.2,3
• Launch power of 10 dBm. IEEE802.3 Interim May 2003 10GBASE-T
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Capacity Calculations • Self-Impairment Cancellation: – 55 dB Return Loss Cancellation (15 dB Hybrid, 40 dB PHY) – 40 dB NEXT Cancellation – 25 dB FEXT Cancellation
• No Established Level for Alien NEXT Mitigation. Mitigation of 0 dB to 25 dB Realized through Combination of One or More Alternatives: – PHY (0 dB to 10 dB)4 – Improved Installation Practices (0 dB to 10 dB)1 – Enhanced Cable Design/Specification (0 dB to 25 dB)5 IEEE802.3 Interim May 2003 10GBASE-T
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Capacity for Different Configuration Options 19
Capacity with Cat5e Alien Model for Different Ins tallation P ractices
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16.6
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17.0
15.9
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14.6
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Capacity (Gb/s )
16.9
14 13
12.7
12 11 10 9 8 prelim alien model prelim alien model, is olated patch cord prelim alien model, is olated patch cord, unbundled cable
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0
5
10
15
20
25
Alien Mitigation (dB)
IEEE802.3 Interim May 2003 10GBASE-T
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Summary • Improved Installation Practices Provide a Viable Means of Alien NEXT Mitigation – Isolated Patch Cords – Separated Patch Panel Ports – Unbundled Cable
• Capacity Greater than 10 Gb/s can be Achieved Using Improved Installation Practices and Reasonable Levels of Impairment Cancellation IEEE802.3 Interim May 2003 10GBASE-T
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References 1Cohen,
L., “Alien Crosstalk Measurements,” IEEE802.3 Contribution, Jan. 2003.
2Pagnanelli,
C., “Data Center Background Noise Measurements,” IEEE802.3 10GBASE-T Contribution, May 2003.
3Cobb,
T., “Background Noise,” IEEE802.3 10GBASE-T Contribution, May 2003.
4Solarflare
Communications, “10GBASE-T Tutorial,” IEEE802.3 Contribution, Nov. 2002.
5Cobb,
T., “Experimental Cat6 Cable Developed with Improved Alien NEXT,” IEEE802.3 Contribution, March 2003.
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