Technical Guide - Pearson VUE

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Technical Guide for NetTest Exam Connectivity System

Version 17.1.2 January 2017

Certiport.com

mailto:[email protected]

2 NetTest Exam Network Connectivity Certiport Confidential

Contents 1. Overview ............................................................................................. 3 2. Technical Requirements .................................................................... 4

System requirements ............................................................................ 4 Required IP Addresses and Protocols .................................................. 4 Region Mappings.................................................................................. 5

3. Support Contacts ............................................................................... 5 4. Architecture ........................................................................................ 6 5. PingPong Protocol ............................................................................. 7 6. Disable sleep and hibernate settings ............................................... 8 7. User Experience ............................................................................... 10

Initial Launch ...................................................................................... 10 Configuring the Tool ........................................................................... 10 Test Center ID or Region missing....................................................... 10 Datastore Unavailable ........................................................................ 11 Test Phase 1 – Computer Settings ..................................................... 11 Test Phase 2 – Check network speed ................................................ 11 Test Phase 3 – Internet Route Trace.................................................. 12 Test Phase 4 – TCP PingPong Session Testing ................................ 12 Test Complete – Normal ..................................................................... 12 Test Complete – User cancelled ........................................................ 13

8. Logfiles .............................................................................................. 13

Trademarks Confidential, Trade Secret, and Unpublished Copyright Materials of Pearson Education, Inc. or its affiliate(s). Created 2017. All rights reserved. Use permitted only under license. For further information, contact Pearson VUE™ or visit Pearsonvue.com. Pearson, Certiport, the Pearson VUE and Certiport logos, and VUE are trademarks, in the U.S. and/or other countries of Pearson Education, Inc. or its affiliate(s). All other products, services, or company names mentioned herein are claimed as trademarks and trade names by their respective companies.

Overview

Certiport Confidential NetTest Exam Network Connectivity 3

1. Overview The NetTest system is designed to allow Certiport Test Centers to check the compatibility of their systems and network connections for cloud-hosted exam environments. Test Centers will be asked to launch a test tool on one of their exam machines, enter data to identify the test center and closest Azure region, then leave the tool running for 24 hours. The test run consists of four phases. No interaction from users is required in any of these phases. During the test run, data is gathered regarding:

1. Local machine configuration 2. Internet speed 3. Internet route to the nearest Azure region 4. Long-term TCP session stability to the nearest Azure region

During the test run, all result data is logged to both an online Azure SQL repository and to a pair of TXT files in the %TEMP% folder. The Azure regions being used for connectivity testing are shown in the map below, highlighted with Red circles:

The specific Azure datacenters being used are as follows:

• West US Datastore for test results

• South Central US TCP Ping Responder

• Northern Europe TCP Ping Responder

• Southeast Asia TCP Ping Responder As far as possible, all network communication will be over TCP port 80, since this provides the most likely open path for communication across Partner firewalls.

Technical Requirements


2. Technical Requirements In order to participate in the NetTest connectivity check, your test center must do the following: Disable sleep and hibernate settings on the exam delivery

workstation that will run NetTest Download and execute the NetTestV2.exe file on one exam delivery

workstation in your test center that is not being used for exam delivery during the 24 hour network connectivity testing period

Have your test center ID ready so you can launch the NetTest Run the NetTest during normal testing hours so we can gather

information on network traffic during a typical testing day Ensure the exam delivery workstation running NetTest runs for

24 continuous hours until the testing is complete

System requirements

The NetTest tool has been designed to operate on a wide range of computer host variants within the standard Certiport specifications. The exam delivery workstation that will run NetTest must comply with the following system requirements.

Operating System Windows 7, Windows 8, or Windows 10

.NET Compatible with .NET 3.5

Other components Compatible with PowerShell v2.0 or higher

Required IP Addresses and Protocols

During the first three phases of operation, Internet bandwidth usage is approximately 1 kbps. During the fourth 24-hour phase this drops to around 5 bps of usage. No noticeable network impact is expected. You must enable the following to ensure network connectivity: Internet connectivity for ICMP (ping) protocol

o Used for Ping and Traceroute testing Internet connectivity for TCP ports 80 and 443

o Used to check HTML5 and TCP connectivity and also to log test results

Support Contacts


The following IP addresses and protocols are needed to cross any site firewall.

Protocol: ICMP ICMP TCP Port 443 TCP Port 80

Asia 67.21.173.142 52.163.229.251 67.21.174.23 52.187.63.240

Europe 67.21.173.142 40.69.39.215 67.21.174.23 52.178.201.160

North America 67.21.173.142 40.84.231.57 13.85.85.101 104.214.26.112

The results datastore that collects the network connection information uses the following DNS registered endpoint: xvnettest.westus.cloudapp.azure.com

Region Mappings

The following Azure regional locations will be used to host the TCP PingPong test and Data API infrastructure behind the NetTest solution.

Azure Regional Center Hosted Service Server Names South Central US NETTEST TCP PingPong NETTESTNA, NETTESTNA-LB

North Europe NETTEST TCP PingPong NETTESTEU, NETTESTEU-LB

Southeast Asia NETTEST TCP PingPong NETTESTAP, NETTESTAP-LB

US West NETTEST Data API NETTESTAPIHOST

NETTEST Database NETTESTDATA (DB name)

3. Support Contacts Ensure you have administrative rights to download and run the executable, verify the workstation meets the minimum technical requirements, check the required IP addresses and protocols to ensure they can cross the firewall, and make sure you can access the Azure DNS endpoint. If you still have issues running the NetTest tool, contact technical support in your region.

• APAC 0097144535360

• EMEA +31 10300 9304

• Americas 1-888-999-9830

http://xvnettest.westus.cloudapp.azure.com/

Architecture


4. Architecture The solution architecture is shown in the diagram below. The NetTest Tool is launched on a Test Center Computer. Once the user has entered the test center ID and region, the tool connects to an Azure SQL dataset (NETTESTDATA) in the West US region, through a Web API hosted on the NETTESTAPI server at the same geolocation.

All test data is logged to this datastore during the test run. The data is tagged with the test center ID and machine serial number for reporting purposes. Once the Computer Settings have been gathered, the tool completes a TraceRoute burst ping pass along the path from the Test Center Computer to the PINGPONG host in the selected Azure region. This process takes up to 60 seconds. Finally, the tool opens a connection to the PingPong host via a load balancer, and initiates a series of PingPong data exchanges. Each PingPong exchange measures the round trip delay in both directions (Client to server/server to client) tagged as Ping and Pong data respectively. Every 10 minutes, the results of these pings are summarized, with calculation of:

• Number of Pings

• Minimum Ping RTT

• Average Ping RTT

PingPong Protocol


• Max Ping RTT

• Ping Jitter

• Number of Pongs

• Minimum Pong RTT

• Average Pong RTT

• Max Pong RTT

• Pong Jitter

• Number of protocol errors (corruption of packets)

• Number of TCP session disconnects This test phase runs for 24 hours. Each 10-minute rollup window is recorded in the Azure SQL datastore and the local TXT logfiles. Note that the period of this TCP PingPong test can be altered for testing purposes. Before starting the test pass, double-click the “Time Remaining” User Interface field to enable it for R/W allowing a new period to be entered in TimeSpan default format (e.g., “0:30” for 30 minutes duration). Press Tab after entry; this locks the value in for the test pass.

5. PingPong Protocol The PingPong protocol is a lightweight TCP socket based solution, which is designed to reliably measure bi-directional round trip times and TCP session stability, but with minimum network overhead and limited server requirements. Bandwidth usage is around 4 B/sec over 24 hours (that’s 4 bytes/sec of bandwidth, combined In/Out). The client establishes a connection with the PingPong server over TCP port 80. The conversation then proceeds as follows: # We exchange text with the server saying PING nnn ttt and expect PONG nnn ttt

# where nnn = The number of the ping

# and ttt = the time in ms between the previous PING/PONG and PONG/ACK

# The conversation between client and server is therefore:

#

# Client: HELO

# Server: OLEH

#

# Client: PING <ping ID> <RTT time for previous PING/PONG response>

# Server: PONG <ping ID> <RTT time for previous PONG/ACK response>

# Client: ACK <ping ID>

Disable sleep and hibernate settings


The client and server initially exchange HELO and OLEH messages to confirm session initiation and to allow the server to spin up a thread without affecting the first ping roundtrip measurement. This also allows the server to identify non-legitimate connections (Internet probes) and close them down. After the initial HELO/OLEH, the client proceeds to send a PING message every 5 seconds. The PING carries an identifier for the exchange (usually increments every round) and also carries the measured PING RTT from the previous exchange. The server responds with a PONG message, carrying the same ID and the previous PONG RTT time. The client then responds with an ACK message, again including the sequence ID, which allows the server to calculate PONG RTT for this exchange. The protocol then resets to expect a new PING exchange, which is repeated at 5 sec intervals.

Note

During the TCP session test:

• PingPong TCP exchanges are sent every 5 seconds

• Results are rolled up every 10 minutes (logged and stored to the Database)

• PingPong network traffic load is ~4 Bytes/second

6. Disable sleep and hibernate settings 1. Open the Control Panel | Power Options.

2. Click Change when the computer sleeps in the left navigation.

Disable sleep and hibernate settings


3. Click the Put the computer to sleep Plugged in drop-down list and select Never.

4. Click the Change Advanced power settings link. 5. Expand the Sleep and Hibernate after setting options. Ensure both

On battery and Plugged in are set to Never.

6. Click OK. 7. Click Save Changes. 8. Close the Control Panel window.

User Experience


7. User Experience The user will experience the following User Interface interactions while configuring and running the tool:

Initial Launch

Configuring the Tool

Test Center ID or Region missing

Vikys Test

North America

User Experience


Datastore Unavailable

Test Phase 1 – Computer Settings

Test Phase 2 – Check network speed

User Experience


Test Phase 3 – Internet Route Trace

Test Phase 4 – TCP PingPong Session Testing

Test Complete – Normal

Logfiles


Test Complete – User cancelled

8. Logfiles The Test tool creates and updates two logfiles locally on the Test Center Computer during the test pass. Any previous file is overwritten during the test run. Both files are stored in the logged on user’s %TEMP% folder. The files can be easily opened by running the following commands at the CMD prompt:

notepad %TEMP%\NetTest.txt

notepad %TEMP%\NetTestRTT.txt

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