fidemo 2009, nov. 18

FIDEMO 2009, Nov. 18A Step Towards a Planet-scale Measurements Retrieval Infrastructure

In this work, we propose to design an end-to-end path and delay estimation service, called Sibilla*. We envision a DNS-like system where applications send queries and receive information on desired metrics, without doing measurements by themselves. The novelty of our system is that we utilize existing measurements and an infrastructure. Our delay estimation is based on a simple idea of path stitching. To provide the path-stitching as a service, we design and deploy our estimation service system on top of the Domain Name System (DNS). We deploy a Sibilla DNS server that receives a query between two hosts and replies with an estimated delay through the DNS interface. We take advantage of the fact that local DNS cache servers are distributed globally and exist in almost all ASes and improve the accuracy of our path stitching algorithm.

Path and delay estimation between any pair of Internet hostsKey assumption: “Many good measurement data are available already.”Decoupling the data collection phase from the data analysisKey Ideas behind path stitching: Internet separates inter- and intra-domain routing;To predict a new path: » Splits paths into AS-level path segments, and » Stitches path segments together » Using BGP routing information

Path-Stitching Algorithm

Demo Scenario

* Sibilla is a female oracle figures in Greek and Roman times, offering cryptic predictions to those who sought to know the future (Sybil in English)

a cInternet path? delay?

aA Cc

aA Cc B

Step 1. IP-to-AS mapping

Step 2. AS path inference

:A: :C::B:

A::B B::C

Step 3. Path stitching

:A::B::C:

Step 4. Rank stitched paths and select the best

Internet Users

BGP routing table snapshots

Traceroute outputs(IPv4 Routed /24 topology data set)

sibilla prototype

RouteViews and RIPE

CAIDA Ark project Contributors

Sibillademo-site

Data contribution

Query

Reply

Advanced Networking Laboratory, KAIST Future Internet Technology Demonstration/Exhibition, November 18, 2009

End-to-end delay graphs are generated on-the-fly

Display statistics of stitched paths

Stitched paths are displayed and animated on the Google Map

Query interface

Rule #1: ProximityRule #2: Destination-bound path segmentsRule #3: Most recent path segments

Source AS Destination ASIntermediate ASes ...

...

Rule #1, 2, 3 Rule #1, 2, 3

Too Many Segments: Preference RulesNo Segments: Approximations

Missing AS:No solutions (other than collecting more data)

Missing inter-domain segments:Search for reverse path segments

Path segments that do not rendezvous at the same address

Use clustering heuristics

System Interface

Demo setup

Local Name Server

Authoritative Name Server(Supporting sibilla.com and

all sub-domains)

DNS query (srcIP_dstIP.latency.sibilla.com)DNS response

1 32 4Path stitching

“An easy interface to a new system is the keyin the system’s success.”

The basic idea of our service system is to formulate a delay query between two hosts as a DNS query and let our Sibilla DNS server answer it. For example, when a user wants to estimate delay between two points A and B, the user submits a DNS query for A_B.latency.sibilla.com. The local DNS server forwards the query to our Sibilla DNS server, which in turn replies with delay estimation.

ConclusionThe beauty of our system lies in the simplicity of the service system design. Any improvement of the path-stitching algorithm in terms of added measurements and better estimation method can be immediately reflected in a deployed system, as the DNS interface cleanly separates the user interface and the estimation mechanism. To change our system from the current off-line version to serve thousands of queries a second, we plan to profile our algorithm and employ appropriate accelerating measures.

:A: :B:

B::A

X

Z

Y

W

A

X::A::W = ?

http://an.kaist.ac.kr/projects/sibillaAbstract