Loss and Delay Loss and Delay Accountability for the Accountability for the InternetInternet

by

Presented by: Eric Chan Kai Chen

OutlineOutlineMotivationFunctionTrustComputation Costs and AccuracySecurityDeployment / ScalabilityFinancial CostsConclusion

MotivationMotivation“ Internet should provide information

about where packets are being dropped or delayed so that end systems can intelligently adapt to current conditions.”

MotivationMotivation“ Internet should provide information about where

packets are being dropped or delayed so that end systems can intelligently adapt to current conditions.”

- The motivation is good, but not well defended, which we will see later…

Resending of packets if dropped◦ Cheap and quick

- Without your AudIt, TCP still can resend the dropped packets. How can you guarantee that you are quicker than TCP?

◦ Multiple path a packet can reach destination

- The problem is can you really control the route you will take to the destinations?

Functions Existing Internet probing

tools such as “ping” and “traceroute” can help debug network problems.

- long-lasting outages or persistent high drop rates, Just works well.

- what do you want to do by getting the information of instantaneous high drop rates/outage? Useful??

- cannot choose another provider due to single-homed

- cannot control its inter-domain routing, this is done by ASes

- the AS can recovery from instantaneous problems.

Probe traffic and data traffic, in order to get the view of performance over the network, why they are different?

AS1

AS3 AS4

AS2

Source Destination

High loss rate, or outage

AS1 AS2Source Destination

High loss rate, or outage

Trust/IncentiveTrust/Incentive Begs the question of how the user can trust the reports if not

everything is revealed? Creates disputes over feedback.

– will ISPs use this, ISPs usually have relationships b/w each other, disputes really hurt their relationship, e.g. providers always like the traffic from it customers, how can providers help users to disclose the problems in its customers?

Do ISPs really have incentive to adopt such kind of “AudIt” system?

By using “AudIt”, an ISP can only control its feedback, it still cannot decrease the people’s interests in digging more confidential information.

Why user will trust the feedback from the ISPs? Since the info is from your providers who earn money from you.

Revealing weakness – users will choose the most reliable

Computation Costs and Computation Costs and AccuracyAccuracyLots of trial and error coming

from accurate delay feedbacks◦ entry point can’t determine the average time

because it cannot know if and where it exits◦ exit point is chosen to determine when and where

packets enter the AD, but there is insufficient information

Guesswork!◦ How accurate?◦ Large amount of computation with so much error

correction

SecuritySecurityNo mention of security

◦Are reports encrypted?

SecuritySecurityNo mention of security

◦Are reports encrypted?

Denial-of-service attacks◦Leaked information to plan attacks

Security would add overhead◦But without security, systems would

be difficult to deploy

Deployment / ScalabilityDeployment / ScalabilityTested on real environment?

◦ 100 nodes do not represent the Internet.◦ How would accuracy and educated guesses

scale with more nodes? ◦ Will overhead increase exponentially?

Deployment / ScalabilityDeployment / ScalabilityTested on real environment?

◦ 100 nodes do not represent the Internet.◦ How would accuracy and educated guesses

scale with more nodes? ◦ Will overhead increase exponentially?

Low overhead simplifies deployment…Physical deployment?

◦ Router/server upgrades

Financial Costs ??Financial Costs ??

ConclusionConclusionNo better than the current

opacity. Lay problems to business

relations.Report accuracy undetermined.Security unimplemented.Deployment and scalability

issues were not addressed.No cost analysis.