Best Practices for Ensuring LAN Performance
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Transcript of Best Practices for Ensuring LAN Performance
Best Practices for Ensuring LAN Performance
Transitioning Networks to Gigabit Ethernet
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Agenda
Main reasons and motivations for moving to Gigabit Ethernet
Ethernet technology overview
Pros and cons of ANSI/EIA/TIA-568-B tests
Step-by-step upgrade process to verify capability of existing pairs to carry 1000BASE-T
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Why transition the desktop to Gigabit Ethernet?
Increasing “need for speed” Streaming audio/video
– VoIP– YouTube– Distance learning– Radio/TV streams
On-Line applications– Presence/Collaboration– Time cards– Expenses– SAP, Oracle, etc.
Decreasing cost– Cost per switch port – Cost per Network Interface
Card (NIC)– Most existing cabling
infrastructure supports it
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10BASE-T
Standard released in 1990 First Ethernet over twisted pair standard Category 3 Cabling Two pairs used – 1 transmit/1 receive Manchester Coding 16 MHz +V
0V
-V
1 1 0 0
Bit Cell Bit Cell Bit Cell Bit Cell
Bit Cell Boundaries
Manchester Encoding
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100BASE-TX
Standard released in mid-1990’s Auto-Negotiation for speed and duplex Category 5 Cabling Two pairs used – 1 transmit/1 receive Multi-Level Transition – 3 (MLT-3) Coding 31.25 MHz
0 0 1 0 1 0 0 0
Actual Bit Stream
MLT-3 Encoding
Bit Recovery
The voltage level changes in succession: +V to 0V to -V to 0V to +V, etc.
The voltage level only changes for a 1 bit
0 V
+ V
- V
0V
+V
-V
0 0 1 0 1 0 0 0
Actual Bit Stream
MLT-3 Encoding
Bit Recovery
The voltage level changes in succession: +V to 0V to -V to 0V to +V, etc.
The voltage level only changes for a 1 bit
0 V
+ V
- V
0V
+V
-V
0V
+V
-V
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1000BASE-T
Standard released in 2000 Category 5 cabling Four pairs used – 250 Mbps per pair full duplex 5 Level Pulse Amplitude Modulation (PAM-5) 80MHz
Clock
0
12-LevelCode
4-LevelCode
11
01
00
10
1 1 1 10 0 0 0
11 10 10
00
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10BASE-T/100BASE-TX Media Dependant Interface
Ethernet devices (NICs in PCs and routers) transmit on pins 1&2 and receive on pins 3&6. Referred to as MDI
Switches and hubs are wired MDI-X (transmit on pins 3&6, receive on pins 1&2)
T568B T568A
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Ethernet Summary
10BASE-T 100BASE-TX 1000BASE-T
Speed 10 Mbps 100 Mbps 1000 Mbps
Frequency 16 MHz 31.25 MHz 80 MHz
Pairs/Pins Used 1-2 NIC Tx
3-6 NIC Rx
1-2 NIC Tx
3-6 NIC Rx
Tx/Rx on all Pairs
1-2, 3-6, 4-5, 7-8
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IEEE 802.3 vs. ANSI/EIA/TIA-568-B.1
802.3– Ethernet standard for rates
from 1Mbps to 10Gbps over coax, twisted pair, and fiber optic cabling
568– Specifies a generic
telecommunications cabling system for commercial buildings
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ANSI/EIA/TIA-568-B.1 Tests – Pros and Cons
Pros– Required for some
cable/connector vendor’s warranty for new installations
– Certifies cable to meet category 5e, 6 or 6A
– Measures a wide range of frequency-based results:
• NEXT
• PSNEXT
• ELFEXT
• PSELFEXT
Cons– Does not prove operation of
Ethernet over cable link– Does not perform Ethernet Bit
Error Rate Test– Does not measure overall
system noise – May fail links that would work
fine for 1000BASE-T
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Transitioning existing networks to 1000BASE-T
See if existing plant can support new speed BEFORE pulling new cables
CAT5 (or better) cabling already installed
No real need to run full EIA/TIA tests
Cost-effective alternative:– Run actual 1000BASE-T signals and analyze for errors– Bit Error Rate Test (BERT)
Step-by-Step Process
Move to 1000BASE-T with confidence!
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Process Overview
Create a test plan Test
– Ensure correct cable is being disconnected– Basic cabling (wiremap/length)– 1000BASE-T tests (SNR, Skew, BERT)
Verify Gigabit connectivity– Port Discovery– Ping
Document results
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Create a Test Plan
What cables are you going to test?
Where do they run from?
Where do they terminate?
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Test - Correct cable being tested?
Hub Flash Cisco Discovery Protocol
– Will ID the switch port
Once SURE, disconnect the cable at the switch and connect remote test device
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Test - Perform basic cabling tests
Remember 10/100 only needed 4 pins but gigabit needs all 8!
Opens/Shorts/Miswires/Split Pairs Length
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Measure Delay Skew and SNR
Skew– Delay differential
SNR– Noise sources: NEXT/FEXT,
echo noise, ambient noise
Signal
Noise
SNR – “Distance” between Signal and Noise
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Bit Error Rate Test
Send actual 1000BASE-T signals (PAM-5) Make sure the data sent from one end get to the
other end without errors
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Connect to new switch port
Disconnect remote test device
Connect cable run to new switch port
Verify new port is configured correctly– Port Discovery
• Auto-Negotiation or manual setting?
• If Auto-Negotiation, what is being advertised?
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Verify Network Layer (IP) connectivity
Obtain IP host configuration– Dynamic Host Configuration Protocol (DHCP)– Or manual configuration
Ping network devices– Router– Domain Name System (DNS)– Any other IP device
Connect upgraded Ethernet device!
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Document Results
Cabling plan– Update documentation for
cabling runs
Test Results– Use for future
reference/troubleshooting
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Summary
For the IT manager– Using existing infrastructure is cost effective– Need to test cabling first– Speed certification ensures 1000BASE-T will work
For the cabling contractor– New revenue opportunities
For everyone– JDSU has the tools and expertise to help make you
successful!
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Questions and Resources?
Q&A
www.JDSU.com/know for:– Validator-NT product information– View Validator-NT product demo– Locate a distributor– See full line of JDSU Network and Enterprise Test solutions
Recorded Webinar will be made available later this week
Contact Us:– [email protected]