What is Actual Internet Speed?

Seung Il Leeseungil.lee@nttict.com

Network Engineer

NTT Com ICT Solutions

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What is confusing you

This is what you signed!

Factors affecting Internet speed

Contents

Before blaming your ISP

How do I confirm the contracted bandwidth?

When ISP hears complaints

So Internet speed is

Lastly before making a decision

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AS2914

This is what you signed for bandwidth!

100Mbps

100MbpsA Customer

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What is confusing you

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100Mbps 100Mbps

Big Differencefrom your

expectancy

What is confusing you

Result from an Internet speed test service

*This kinds of service is pretty inaccurate due to the fact that testing sites are on shared bandwidth, borrowed networks and ignoring other factors.

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Factors affecting Internet speed

Factors Possible Causes

Traffic congestion • Usage increase• Huge malicious traffic (eg. DDoS attack)• Possible traffic congestion at the destination• Sudden increased traffic at a public/private peer point

between ASs• Faulty device at an ISP

(Increased) Latency • Physical distance• Unforseen asymmetric routing caused by routing policy

changes made in 3rd ISP• Submarine cable cuts (eg. due to natural disasters like

earthquake)• Faulty device at Layer 1 service provider

Application • Non-optimal application protocols being used• Client or server side in being heavily loaded

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• Traffic congestion - Unexpected huge malicious traffic (eg. NTP Reflection attack)

Factors affecting Internet speed

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• Sudden increased traffic at a public/private peer point btw ASs

Factors affecting Internet speed

Path #1 Customer-AS2914-AS4837-AS4808

#trace 203.93.124.72

1 202.93.109.248 1 msec 2 202.68.67.149 [AS 2914] 1 msec 1 msec 0 msec 3 202.68.64.162 [AS 2914] 1 msec 1 msec 1 msec 4 129.250.3.237 [AS 2914] 181 msec 114 msec 115 msec 5 219.158.27.65 [AS 4837] 320 msec 317 msec 6 219.158.97.181 [AS 4837] 295 msec 7 219.158.97.185 [AS 4837] 327 msec * 324 msec 8 123.126.0.210 [AS 4808] 300 msec * 299 msec 9 61.148.153.138 [AS 4808] 300 msec 10 61.148.158.242 [AS 4808] 302 msec * 303 msec 11 61.148.123.94 [AS 4808] 307 msec 301 msec 302 msec 12 * * *

Path #2 Customer-AS1221-AS4637-AS4837-AS4808

#trace 203.93.124.72

1 139.130.63.73 [AS 1221] 1 msec 1 msec 0 msec 2 203.50.20.129 [AS 1221] 5 msec 3 msec 4 msec 3 203.50.6.90 [AS 1221] 3 msec 4 msec 4 msec 4 203.50.13.18 [AS 1221] 4 msec 4 msec 4 msec 5 202.84.144.85 [AS 4637] 116 msec 117 msec 116 msec 6 202.84.143.42 [AS 4637] 119 msec 120 msec 119 msec 7 134.159.100.42 [AS 4637] 118 msec 119 msec 118 msec 8 219.158.3.129 [AS 4837] 123 msec 124 msec 123 msec 9 219.158.96.249 [AS 4837] 124 msec 123 msec 123 msec 10 219.158.3.69 [AS 4837] 125 msec 125 msec 125 msec 11 219.158.100.161 [AS 4837] 167 msec 168 msec 169 msec 12 202.96.12.214 [AS 4808] 169 msec 167 msec 167 msec 13 124.65.60.78 [AS 4808] 167 msec * 14 61.148.158.242 [AS 4808] 166 msec 166 msec 166 msec 15 61.148.123.94 [AS 4808] 169 msec 170 msec 167 msec 16 * * *

Congested especially during peak business hour

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Factors affecting Internet speed

• Physical distance - Simulation showing how increased latency affects internet speed.

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• Unforseen asymmetric routing caused by routing policy changes made in 3rd ISP

Factors affecting Internet speed

Tier 1AS2914

Tier 2ASYYYYY

Tier 1ASXXXXX

A Customer

xxx.xxx.xxx.0/24

Destination

AUST

US

After changeBefore change

AUST

US

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• Increased latency due to a submarine cable cut

Factors affecting Internet speed

Complaint about routes to China

Tracing the route to 120.85.133.203 1 210.50.55.33 76 msec 0 msec 0 msec 2 203.134.72.97 [AS9443] 0 msec 0 msec 4 msec 3 203.134.2.110 128 msec 124 msec 148 msec 4 203.192.129.245 124 msec 128 msec 124 msec 5 61.14.157.102 188 [AS10026] msec 184 msec 184 msec 6 121.189.2.105 188 [AS4766] msec 184 msec 188 msec 7 112.174.87.97 236 msec 236 msec 232 msec 8 112.174.83.221 256 msec 252 msec 9 112.174.83.226 252 msec 10 219.158.34.209 [AS4837] 476 msec 480 msec 11 219.158.97.245 488 msec * 488 msec 12 219.158.3.25 492 msec * * 13 219.158.98.186 520 msec 532 msec 536 msec 14 219.158.99.134 480 msec 488 msec 488 msec 15 120.83.0.90 480 msec 492 msec 496 msec 16 120.80.175.130 484 msec 488 msec 496 msec *

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Factors affecting Internet speed

• Non-optimal application protocols being used - Simulation result exactly matches with the actual bandwidth usage of a specific application protocol.

Actual maximum usage

Simulation based on the specific application

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So Internet speed is

Physics terminology says

However in Internet,

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Before blaming your ISP

• Bandwidth Congested? Check traffic usage of your WAN bandwidth. Try ping and check overall latency and packet drops. Try traceroute to check where any hop in your LAN has high

latency.• Asymmetric routing?

Try traceroute in both direction, if possible, and compare the result.

• Speed decrease after introducing new application? Try download files using FTP and compare the result.

• Speed decrease for a specific destination? Check asymmetric routing btw source & destination Check the status of the specific source & destination.

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When ISP hears complaints

Request Traceroute with Source/Destination IP if not provided.

Check any outage related with the issue.

Check Asymmetric routing

Inform customer of the outage

Try to resolve the asymmetric routing by working with other AS

Check a security issue like DDoS

Security team try to resolve the issue

No issue found?

Explain the situation is expected in a specific situation reported.

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How do I confirm the contracted bandwidth?

• Request an access line test result on the contracted bandwidth

• Do a quick test using FTP protocol between two locations or from a well-known public file sharing site (ex. Microsoft MSN)

• Request a test using iPerf (https://iperf.fr/) (NTT Com runs iPerf servers globally.)

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Lastly before making a decision

• Check global latency & your specific destination through Looking Glass or Route Server