Anycast

Last month I noticed quite high latency with Cisco’s OpenDNS from my home fibre connection. The provider at home is IAXN (AS134316) which is peering with content folks in Delhi besides transit from Airtel.

ping -c 5 208.67.222.222
PING 208.67.222.222 (208.67.222.222) 56(84) bytes of data.
64 bytes from 208.67.222.222: icmp_seq=1 ttl=51 time=103 ms
64 bytes from 208.67.222.222: icmp_seq=2 ttl=51 time=103 ms
64 bytes from 208.67.222.222: icmp_seq=3 ttl=51 time=103 ms
64 bytes from 208.67.222.222: icmp_seq=4 ttl=51 time=103 ms
64 bytes from 208.67.222.222: icmp_seq=5 ttl=51 time=103 ms
--- 208.67.222.222 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 103.377/103.593/103.992/0.418 ms

This is bit on the higher side as from Haryana to Mumbai (OpenDNS locations list here). My ISP is backhauling from Faridabad which is probably 6-8ms away from my city and 2-3ms further to Delhi and from there to Mumbai around 30ms. Thus latency should be around ~40-45ms.

Day before yesterday i.e on 18th August 2016 Bangladesh’s TLD .bd went had an outage. It was originally reported by Jasim Alam on bdNOG mailing list.

dig btcl.com.bd @8.8.8.8
; <<>> DiG 9.10.4-P2 <<>> btcl.com.bd @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 8114
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;btcl.com.bd.                   IN      A
;; Query time: 76 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Aug 18 14:24:25 Bangladesh Standard Time 2016
;; MSG SIZE  rcvd: 40

His message shows that DNS resolution of BTCL (Bangladesh Telecommunications Company Ltd) was failing. Later Alok Das that it was the power problem resulting in outage. Let’s look ask one of 13 root DNS server about NS records on who has the delegation for .bd.

I just presented data on Performance of Root DNS anycast in UK & Ireland at INEX meeting.

Enjoyed ISC’s presentation about their analysis of F root server (one 13 root DNS servers which power the Internet) about anycast performance gloablly for 192.5.5.0/24 announced (and anycasted) by AS3557 (ISC). This was presentation at UKNOF 32.

Embedded presentation below (or click here to watch on YouTube directly)