Continuous Data-driven Analysis of Root
Stability (CDAR)
Preliminary Results
Giovane C. M. Moura
SIDN LabsIEPG - IETF 95
Buenos Aires, Argentina
April 3rd, 2016

Context

I Together with NLNet Labs and TNO, we’ve won a RFP fromICANNI CDAR project:
I RQ: What’s the impact of the new gTLD program on theRoot DNS stability?
I ApproachI

Data-driven, using wide variety of DNS data

I Interaction with the broader tech community
I

ICANN and advisory committees, RSOs, DNS-OARC,IEPG/IETF

DNS Root and name resolutionroot(1) example.nl.nl
Figure: Resolving a NameDNS Root and name resolution(2) .nl ?

root(1) example.nl.nl
Figure: Resolving a NameDNS Root and name resolution(2) .nl ?

root(1) example.nl(3) .nl is ...

.nl
Figure: Resolving a NameDNS Root and name resolution(2) .nl ?

root(1) example.nl(3) .nl is …
(4) example.nl ?

.nl
Figure: Resolving a NameDNS Root and name resolution(2) .nl ?

root(1) example.nl(3) .nl is …
(4) example.nl ?
(5) example.nl is ..

Figure: Resolving a Name.nl

DNS Root and name resolution(2) .nl ?

root(1) example.nl(3) .nl is …
(4) example.nl ?

(6) example.nl is(5) example.nl is ..

Figure: Resolving a Name.nl

The Root DNS System

I Lists records for TLDs
I Extremely redundant to improve performance and availability:

13 letters (A through M)
I Each letter hosts several to more than 100 servers (Anycast)
I Distributed all over the world
I Has been up and running for many years
II Survived some major DDoS attacks
I Letters are ran by different organizations worldwide
I It’s dynamic: more servers, lines added frequently

How many TLDs are out there?
1100
1000
Root Zone size

900
800
700
600
500
400
300

Date

Figure: Timeseries of TLDs in the Root Servers

Is it too many? .com has 126+ million domains

01/01/2016

01/01/2014

01/01/2012

01/01/2010

01/01/2008

01/01/2006

01/01/2004

01/01/2002

01/01/2000

01/01/1998

200

What’s the root traffic like (DITL = 1 day/year)

Figure: DITL data ! new gTLD traffic is still too small

Correlation between TLDs size and number of rootqueries
TLD.com.org.cn.br.club.xyz

Queries779.171.677
91.095.714
51.949.760
15.696.021
651.082420.885

Zone Size
120.585.440
10.569.583
11.678.026
3.568.492
202.519842.340

Ratio
6.46
8.62
4.45
4.40
3.21
0.50

Table: DITL 2015 Data for K-root - Valid Queries onlyI Ratio rarely exceeds 10 for DITL 13, 14, 15 , and recent H-root
I new gTLDs ratios are lower
I Limitation datasets: 1 day only per year
I

hard to generalize

So far:I DITL data set is great; but it is a snapshot

Hard to generalize conclusions
I Have to combine with other analysis
II Is there any other longitudinal dataset out there?

YES! RIPE Atlas monitors every single root server letter :)I Every 4 min (except A)
I They’ve been doing this for YEARS now
I Limitation: influenced by other network errors
I Pro: a good approximation of a resolver
IActive Measurements with RIPE Atlasi1
vp1

vp2

s1

↵

vpn

s2

sn

I We can measure RTT, errors, on various levels:letter (↵ = A-M)
I site (s = city)
nI instance/server (i = actual machine)nIi2inMeasurement plan with RIPE Atlas

1. Choose 30 dates in which new gTLDs were included in theroot zone in the last years
2. For each day d, gets -2 and +2 days of data from RIPE Atlas ,for each letter
3. Analyze RTT, responses per root server letter, site, and server

We have some preliminary results

16 New TLDs: changes overall performance?

10 New TLDs: changes overall performance?

New gTLDs: changes overall performance?

I We are still working on the RIPE data
I Statistical tests to determine if there’s variation
I So far, it seems to not impact that much

Root DNS is very robust
I It’s designed to “take the punch”
I It would be weird to see major problems
II Other events can happen: DDoS Nov 30th/Dec 1stI

See Matt Weinberg/Duane Wessels (A/J Root) DNS OARC
Presentation

Summary

I Study aims at determining impact of new gTLD on Root DNS

stability/security
I Various datasets; each one with its own limitation
I So far, new gTLD seem to have no significant impact the Root

DNS system
I Next: continue our analysis to draw final conclusions
I

More metrics, more data, more analysis

Questions?
CDAR Project TeamI Bart Gijsen (TNO)
I Benno Overeinder (NLnet Labs)
I Cristian Hesselman (SIDN)I Daniël Worm (TNO)
I Giovane C. M. Moura (SIDN)
I Jaap Akkerhuis (NLnet Labs)

Giovane C. M. Moura CDAR website: