Tata-Communications

Private IPs in Public routing

Networking

Sometimes we see interesting IP’s in traceroute & they confuse lot of people.

I have seen this topic in discussion twice on NANOG and once on Linux Delhi user group. 

OK - let’s pick an example: 

anurag:~ anurag$ traceroute 71.89.140.11
traceroute to 71.89.140.11 (71.89.140.11), 64 hops max, 52 byte packets
1 router (10.10.0.1) 1.176 ms 0.993 ms 0.941 ms
2 117.220.160.1 (117.220.160.1) 20.626 ms 29.101 ms 19.216 ms
3 218.248.169.122 (218.248.169.122) 23.983 ms 43.850 ms 45.057 ms
4 115.114.89.21.static-mumbai.vsnl.net.in (115.114.89.21) 118.094 ms 81.447 ms 66.838 ms
5 172.31.16.193 (172.31.16.193) 115.979 ms 90.947 ms 90.491 ms
6 ix-4-2.tcore1.cxr-chennai.as6453.net (180.87.36.9) 95.778 ms 98.601 ms 98.920 ms
7 if-5-2.tcore1.svw-singapore.as6453.net (180.87.12.53) 321.174 ms
if-3-3.tcore2.cxr-chennai.as6453.net (180.87.36.6) 331.386 ms 326.671 ms
8 if-6-2.tcore2.svw-singapore.as6453.net (180.87.37.14) 317.442 ms
if-2-2.tcore2.svw-singapore.as6453.net (180.87.12.2) 334.647 ms 339.289 ms
9 if-7-2.tcore2.lvw-losangeles.as6453.net (180.87.15.26) 318.003 ms 328.334 ms 309.234 ms
10 if-2-2.tcore1.lvw-losangeles.as6453.net (66.110.59.1) 306.500 ms 326.194 ms 341.537 ms
11 66.110.59.66 (66.110.59.66) 315.431 ms 330.417 ms 308.372 ms
12 dls-bb1-link.telia.net (213.155.136.40) 354.768 ms 344.360 ms 357.050 ms
13 chi-bb1-link.telia.net (80.91.248.208) 352.479 ms 358.751 ms 359.987 ms
14 cco-ic-156108-chi-bb1.c.telia.net (213.248.89.46) 367.467 ms 370.482 ms 377.280 ms
15 bbr01aldlmi-bue-4.aldl.mi.charter.com (96.34.0.98) 387.269 ms 385.362 ms 365.694 ms
16 crr02aldlmi-bue-2.aldl.mi.charter.com (96.34.2.11) 375.275 ms 375.356 ms 371.621 ms
17 dtr02grhvmi-tge-0-1-0-0.grhv.mi.charter.com (96.34.34.83) 383.539 ms 371.817 ms 383.804 ms
18 dtr02whthmi-tge-0-1-0-0.whth.mi.charter.com (96.34.34.85) 384.400 ms 391.197 ms 393.340 ms
19 dtr02ldngmi-tge-0-1-0-0.ldng.mi.charter.com (96.34.34.87) 371.192 ms 375.679 ms 378.457 ms
20 acr01mnplmi-tge-0-0-0-3.mnpl.mi.charter.com (96.34.40.75) 364.824 ms 385.534 ms 374.401 ms
21 * *^C
anurag:~ anurag$

Let’s try pinging IP on 14th hop (which is with a major backbone Telia) - 213.248.89.46

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Backend of Google's Public DNS

Networking

And finally academic session over. Done with all vivas and related stuff. Next will be exams likely in June. Time for me to get ready for travel. :)   Anyways an interesting topic for today’s post - Google Public DNS. Lot of us are familier with popular (and free) DNS resolvers 8.8.8.8 and 8.8.4.4. I have covered reason in previous posts on why it tends to fail with Content Delivery networks like Akamai which rely on anycasting at bottom DNS layer and simple unicasting on application servers. Anycasted DNS nodes point to application servers based on various factors like distance, load, cost etc out of interesting algorithms these CDN networks use for load & cost management.   Anyways today’s post focus is not CDN issues with these resolvers but Google Public DNS itself. Are these servers located in India and everywhere else where Google has PoPs?   Let’s do a simple trace to get forward path from Airtel to Google’s 8.8.8.8:

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SMW4 Cable outage

Networking

Today a friend from Pakistan informed about SMW4 outage. He reported about issues in Pakistan.

It seems like SMW4 is damaged near Egypt and that is what causing high load on East Asian routes giving pretty high latency.

I am at my home and sitting BSNL’s network and latency with Europe has jumped terribly to 700-800ms. Right now I do not see a direct route to Europe and it’s rather taking East Asia > US > Europe routes right now on other cable networks.

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BSNL routing tables and upstreams

Networking

Just was looking at routing tables of BSNL. They have a significant address space in /10 - 117.192.0.0/10. Overall this /10 address space is divided into /18 and /20 subnets.

Let’s pick two of such subnets and observe routing tables from route-views:

  1. 117.192.0.0/18
  2. 117.192.0.0/20 

Routing table for 117.192.0.0/18: 

* 117.192.0.0/18 193.0.0.56 0 3333 3356 6453 4755 9829 9829 9829 i  
* 194.85.102.33 0 3277 3216 6453 4755 9829 9829 9829 i  
* 194.85.40.15 0 3267 174 6453 4755 9829 9829 9829 i  
* 129.250.0.11 6 0 2914 6453 6453 4755 9829 9829 9829 i  
* 128.223.253.10 0 3582 3701 3356 6453 4755 9829 9829 9829 i  
* 4.69.184.193 0 0 3356 6453 4755 9829 9829 9829 i  
* 209.124.176.223 0 101 101 3356 6453 4755 9829 9829 9829 i  
* 69.31.111.244 3 0 4436 2914 6453 6453 4755 9829 9829 9829 i  
* 207.46.32.34 0 8075 6453 4755 9829 9829 9829 i  
* 66.59.190.221 0 6539 6453 4755 9829 9829 9829 i  
* 12.0.1.63 0 7018 6453 4755 9829 9829 9829 i  
* 208.74.64.40 0 19214 2828 6453 4755 9829 9829 9829 i  
* 203.181.248.168 0 7660 2516 6453 4755 9829 9829 9829 i  
* 66.185.128.48 111 0 1668 6453 4755 9829 9829 9829 i  
* 134.222.87.1 0 286 6453 4755 9829 9829 9829 i  
* 157.130.10.233 0 701 6453 4755 9829 9829 9829 i  
* 114.31.199.1 0 0 4826 6939 1299 6453 4755 9829 9829 9829 i  
* 89.149.178.10 10 0 3257 6453 4755 9829 9829 9829 i  
* 154.11.98.225 0 0 852 3561 6453 4755 9829 9829 9829 i  
* 202.249.2.86 0 7500 2497 6453 4755 9829 9829 9829 i  
* 154.11.11.113 0 0 852 3561 6453 4755 9829 9829 9829 i  
* 144.228.241.130 0 1239 6453 4755 9829 9829 9829 i  
* 217.75.96.60 0 0 16150 1299 6453 4755 9829 9829 9829 i  
* 207.172.6.20 0 0 6079 3356 6453 4755 9829 9829 9829 i  
* 206.24.210.102 0 3561 6453 4755 9829 9829 9829 i  
* 195.66.232.239 0 5459 6453 4755 9829 9829 9829 i  
* 208.51.134.254 2523 0 3549 6453 4755 9829 9829 9829 i  
* 207.172.6.1 0 0 6079 3356 6453 4755 9829 9829 9829 i  
* 216.218.252.164 0 6939 1299 6453 4755 9829 9829 9829 i  
* 203.62.252.186 0 1221 4637 6453 4755 9829 9829 9829 i  
*> 66.110.0.86 0 6453 4755 9829 9829 9829 i  
* 164.128.32.11 0 3303 6453 4755 9829 9829 9829 i  
* 202.232.0.2 0 2497 6453 4755 9829 9829 9829 i

Routing table for 117.192.0.0/20:

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