best practices for ensuring lan performance

Best Practices for Ensuring LAN Performance

Transitioning Networks to Gigabit Ethernet

© 2008 JDSU. All rights reserved. 2

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


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


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


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


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


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


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


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


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


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!


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


Create a Test Plan

What cables are you going to test?

Where do they run from?

Where do they terminate?


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


Test - Perform basic cabling tests

Remember 10/100 only needed 4 pins but gigabit needs all 8!

Opens/Shorts/Miswires/Split Pairs Length


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


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


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?


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!


Document Results

Cabling plan– Update documentation for

cabling runs

Test Results– Use for future

reference/troubleshooting


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!


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]

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