What is Actual Internet Speed? Seung Il Lee Network Engineer NTT Com ICT Solutions

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 2 So Internet speed is Lastly before making a decision

AS2914 This is what you signed for bandwidth! 100Mbps A Customer 3

What is confusing you 4

100Mbps Big Difference from 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. 5

Factors affecting Internet speed FactorsPossible 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 3 rd 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 6

Traffic congestion - Unexpected huge malicious traffic (eg. NTP Reflection attack) Factors affecting Internet speed 7

Sudden increased traffic at a public/private peer point btw ASs Factors affecting Internet speed Path #1 Customer-AS2914-AS4837-AS4808 #trace msec [AS 2914] 1 msec 1 msec 0 msec [AS 2914] 1 msec 1 msec 1 msec [AS 2914] 181 msec 114 msec 115 msec [AS 4837] 320 msec 317 msec [AS 4837] 295 msec [AS 4837] 327 msec * 324 msec [AS 4808] 300 msec * 299 msec [AS 4808] 300 msec [AS 4808] 302 msec * 303 msec [AS 4808] 307 msec 301 msec 302 msec 12 * * * Path #2 Customer-AS1221-AS4637-AS4837-AS4808 #trace [AS 1221] 1 msec 1 msec 0 msec [AS 1221] 5 msec 3 msec 4 msec [AS 1221] 3 msec 4 msec 4 msec [AS 1221] 4 msec 4 msec 4 msec [AS 4637] 116 msec 117 msec 116 msec [AS 4637] 119 msec 120 msec 119 msec [AS 4637] 118 msec 119 msec 118 msec [AS 4837] 123 msec 124 msec 123 msec [AS 4837] 124 msec 123 msec 123 msec [AS 4837] 125 msec 125 msec 125 msec [AS 4837] 167 msec 168 msec 169 msec [AS 4808] 169 msec 167 msec 167 msec [AS 4808] 167 msec * [AS 4808] 166 msec 166 msec 166 msec [AS 4808] 169 msec 170 msec 167 msec 16 * * * Congested especially during peak business hour 8

Factors affecting Internet speed Physical distance - Simulation showing how increased latency affects internet speed. 9

Unforseen asymmetric routing caused by routing policy changes made in 3 rd ISP Factors affecting Internet speed Tier 1 AS2914 Tier 2 ASYYYYY Tier 1 ASXXXXX A Customer xxx.xxx.xxx.0/24 Destination AUST US After change Before change AUST US 10

Increased latency due to a submarine cable cut Factors affecting Internet speed Complaint about routes to China Tracing the route to msec 0 msec 0 msec [AS9443] 0 msec 0 msec 4 msec msec 124 msec 148 msec msec 128 msec 124 msec [AS10026] msec 184 msec 184 msec [AS4766] msec 184 msec 188 msec msec 236 msec 232 msec msec 252 msec msec [AS4837] 476 msec 480 msec msec * 488 msec msec * * msec 532 msec 536 msec msec 488 msec 488 msec msec 492 msec 496 msec msec 488 msec 496 msec * 11

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 12

So Internet speed is 13

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. 14

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. 15

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 ( (NTT Com runs iPerf servers globally.) 16

Lastly before making a decision Check global latency & your specific destination through Looking Glass or Route Server 17