Posts Tagged ‘myrepublic’

Why NUS-to-MyRepublic latency is so high?

2013/08/16

I have switched from starhub cable to MyRepublic fibre. I noticed the lag when SSH from home to NUS, so I tried to figure it out.

Here is a comparison of the round trip time (RTT) from MyRepublic to various of places I can think of. The measurement spams about one and half days. 5 ping packets is sent to all targets every 20 minutes. Sorry for the limited coloring of the plot. The legend is sorted from low latency on the top to high latency on the bottom. So singnet is the fastest and berkeley is the slowest. NUS, having an average RTT of 189ms, ranks among the slowest three.

Image

Here is a summary in the following table. I got geographic location from http://www.iplocation.net.

host geo. location RTT
http://www.singnet.com.sg Singapore 4.4
speedtest.starhub.com Singapore 5.1
http://www.sutd.edu.sg Singapore 6.4
google dns California 11.7
http://www.sina.com.cn Guangdong 42.4
http://www.tsinghua.edu.cn Beijing 81.4
http://www.fudan.edu.cn Shanghai 144.6
http://www.youku.com Beijing 159.6
http://www.nus.edu.sg Singapore 188.8
http://www.mit.edu Massachusetts 191.3
http://www.berkeley.edu California 223.5

Then I traceroute from MyRepublic to NUS.

[myrepublic]$ traceroute www.nus.edu.sg
traceroute to www.nus.edu.sg (137.132.21.27), 30 hops max, 60 byte packets
 1  192.168.0.2 (192.168.0.2)  0.212 ms  0.412 ms  0.495 ms
 2  172.24.0.1 (172.24.0.1)  2.737 ms  2.736 ms  2.910 ms
 3  192.168.255.2 (192.168.255.2)  6.822 ms  6.837 ms  6.771 ms
 4  203.117.132.9 (203.117.132.9)  4.172 ms  4.296 ms  4.154 ms
 5  anatll11.starhub.net.sg (203.118.7.34)  4.809 ms  4.861 ms  4.764 ms
 6  203.116.10.186 (203.116.10.186)  189.093 ms  188.329 ms  188.602 ms
 7  xe-5-2-0.cc-rtr1.gigapop.nus.edu.sg (202.51.240.34)  177.459 ms  178.062 ms  178.173 ms
 8  nus-gw1.gigapop.nus.edu.sg (202.51.241.14)  178.442 ms  178.512 ms  178.423 ms
 9  * * *

The route seems OK in the sense that every intermediate host are in Singapore. It’s just the RTT which isn’t right. Could the return route be the problem? Then I traceroute from NUS to MyRepublic. Note that 103.6.151.113 is in MyRepublic.

[nus]$ traceroute 103.6.151.113
traceroute to 103.6.151.113 (103.6.151.113), 30 hops max, 60 byte packets
 1  137.132.83.6 (137.132.83.6)  0.339 ms  0.370 ms  0.458 ms
 2  core-e-m.comp.nus.edu.sg (172.18.176.137)  0.315 ms  0.376 ms  0.437 ms
 3  core-j-211.comp.nus.edu.sg (172.18.176.34)  1.216 ms  1.115 ms  1.114 ms
 4  core-k-211.comp.nus.edu.sg (172.18.176.35)  1.231 ms  1.294 ms  1.142 ms
 5  187-9.priv.nus.edu.sg (172.18.187.9)  1.234 ms  1.330 ms  1.580 ms
 6  21-74.priv.nus.edu.sg (172.18.21.74)  1.763 ms  1.420 ms  1.421 ms
 7  border1-cc-l3-po110.priv.nus.edu.sg (172.18.20.102)  1.934 ms  1.985 ms  2.174 ms
 8  border-cc-m1.nus.edu.sg (137.132.3.130)  2.553 ms  3.706 ms  4.776 ms
 9  xe-5-3-0.cc-rtr1.gigapop.nus.edu.sg (202.51.241.13)  4.627 ms  4.120 ms  4.155 ms
10  ge-1-1-0.la-rtr1.gigapop.nus.edu.sg (202.51.240.193)  212.824 ms  212.802 ms  233.477 ms
11  he.net.coresite.com (206.223.143.122)  194.115 ms  214.906 ms  194.099 ms
12  10gigabitethernet2-1.core1.lax1.he.net (72.52.92.121)  192.053 ms  191.509 ms  199.569 ms
13  pacnet.10gigabitethernet2-3.core1.lax1.he.net (216.218.223.206)  191.899 ms  193.382 ms  193.344 ms
14  te0-2-0-0.gw1.lax3.asianetcom.net (61.14.158.48)  188.949 ms  190.592 ms  189.575 ms
15  te0-3-0-1.wr1.sin0.asianetcom.net (61.14.158.49)  204.286 ms  193.958 ms  197.660 ms
16  * gi4-0-0.gw2.sin3.asianetcom.net (61.14.157.134)  205.614 ms  204.824 ms
17  te0-0-0-4.gw3.sin3.asianetcom.net (202.147.32.101)  191.739 ms  191.265 ms  193.485 ms
18  MYR-0001.asianetcom.net (203.192.154.154)  227.445 ms  188.560 ms  227.428 ms
19  10GE-103-6-148-30.myrepublic.com.sg (103.6.148.30)  240.193 ms  240.195 ms  240.204 ms
20  * * *
21  103-6-151-113.myrepublic.com.sg (103.6.151.113)  192.013 ms  193.590 ms  193.314 ms
22  103-6-151-113.myrepublic.com.sg (103.6.151.113)  203.320 ms  195.278 ms  191.638 ms

Notice that in hop 10-11, it goes from NUS to coresite.com, which is in California. It then goes to asianetcom.net, which is in Tokyo. Then it comes back to Singapore. Why it routes like that is beyond my knowledge.

Besides this, another interesting question is that why google dns is so fast. The distance between Singapore and San Francisco is 13572.66 KM. The RTT of light is 90.5ms, so no one can do better than that. But google can do 11.7ms!

It turns out that 8.8.4.4 is an anycast address which means it routes to one of the google DNS servers distributed across the world. Try yourself traceroute to 8.8.4.4!

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