Report onAn Analysis of wide-area Name Server traffic

SubjectAdvance Operating System

Submitted ToMr. Asim Munir

ClassMSCS-F14

Prepared By:Sunawar KhanReg. No: 813-MSCS-F14

Date27th May, 2015

Table of Contents

Abstract.....................................................................................................................................................2

Introduction..............................................................................................................................................2

Literature Survey....................................................................................................................................3

Research Paper #1:............................................................................................................................3

Research Paper #2:............................................................................................................................4

Research Paper #3:............................................................................................................................5

A Comparative Study:...........................................................................................................................5

References:..............................................................................................................................................7

Abstract

World largest distributed database in DNS, millions of computers are connected with each other. DNS is fairly large source of wide-area RPC-Like Traffic.

In year 1991,a research paper reported that eight percent of the packets and four percent of the bytes are travel across NFS net due to DNS. In this paper, the author formally discussed the performance of DNS, caching, retransmission timeout calculation. Using different algorithms, how can DNS resiliency lead to disastrous consequences when certain implementation faults are trigged?

Introduction

DNS associates hostnames with their respective IP addresses, so as when users want to connect to other machines on the network, they can refer to them by name without having to remember IP addresses.

The Domain Name System (DNS) is the world’s most distributed database. DNS is a distributed, replicated name service whose primary purpose is to map host names into corresponding Internet addresses, map Internet addresses into hostnames. Real Word Problem related to DNS is that, DNS consumed twenty times more wide-area network bandwidth unnecessarily.

DNS client software is known as a resolver. At least a dozen resolver implementations exist. Some of these implementations have been re-released to repair various bugs. Some of these implementations have been re-released to repair various bugs.

Caching: DNS server cache responses of successful quires.

Retransmission Algorithms: All DNS transactions employ the UDP unreliable datagram protocol to avoid the additional messages and latency to set up and tear down a TCP connection.

Resolver algorithm: The resolver sends the query to the first of the three servers and waits for a timeout.

Name Server Algorithm: A canonical name is an alias for the query name; for example, castor. USC.edu is an alias for girtab.USC.edu. The server limits itself to a total of 20 referrals or 8 canonical name substitutions.

Literature Survey

As a part of literature review we studied several Domain Name Service related papers and have chosen three latest papers. The motivation behind right selection of papers is

to identify the relationship among first paper (published in 1991) till up-to-date research being advanced in which manner and direction.

Research Paper #1:

Research paper [2] addresses about an enhancement to the conventional Round Robin DNS load balancing technique which allows a single domain name to be associated with several web server IP addresses in a rotated order in a server cluster. Once the DNS server resolves the domain name to one of the web server IP address, the subsequent requests from the same client will be sent to the same server regardless of the current condition of the server. However, this conventional load balancing technique has a few disadvantages.

Approach: The paper presents a new approach to enhance the DNS load balancing services to be more intelligent in load distribution. The DNS server is taking consideration of the status of the servers and will be distributing the services requests based on the performance matrix of the servers in the cluster.

Technique enhanced: The Round Robin DNS Load Balancing is a technique that providing a high level of availability of some services such as webs site, ftp or others services. It also uses to balance the load between the multiple servers to prevent overloading a single server. In this paper a new approach is proposed to enhance the Round Robin DNS load balancing by introducing a new performance indexing algorithm and a task distribution scheduler at the DNS server.

Results are presented in controlled environment using Simulation.

Conclusion: performance of a load balancing system can be further enhanced if the right parameters are being taken into account in task or request distribution. Hence, the proposed algorithm in paper has indicated that by optimizing the load balancing scheme based on the right performance parameters, higher system efficiency can be achieved.

Research Paper #2:

Research paper [3]enhances end-user experiences, Content Distribution Networks (CDNs) effectively exploit the Domain Name System (DNS) to redirect end-users to close-by content replicas over short time scales. While the use of DNS has brought a significant advantage to CDNs, in this paper we confirm that reliance on DNS also poses a fundamental threat to large-scale CDNs’ content distribution model. In particular, we demonstrate that a considerable penetration of public DNS resolving services (e.g., OpenDNS and GoogleDNS)effectively corrupts the CDN approach, equally the large-scale server distribution and quick DNS redirections.

Technique enhanced in this paper: First, we systematically evaluate and quantify how the use of publicDNS resolving services impacts Akamai’s content distribution model, the corresponding end-user service performance, and ISPs that host CDN edge servers. Second, we show that a CDN-based DNS architecture, which can effectively function as both the current authoritative name servers and resolvers, coexist with the current DNS infrastructure, and directly response end-users with authoritative DNS records. Third, we implement a prototype CDN-based DNS system by using popular Web 2.0 websites as a vehicle to publish DNS records onto CDN edge servers. We demonstrate that in an extreme setting, such an approach can achieve one order of magnitude faster lookup times relative to existing DNS resolving systems.

New Approach Proposed: This paper demonstrates that CDNs are not only to be another DNS provider, but also can comprehensively address DNS problems and provide a fundamentally different DNS service, yet superior. Some of the CDNs (e.g., Google) have involved the name resolving service and they have strong incentive to improve their services.

In this paper a comparison of DNS architectures is performed and a new Prototype implementation is proposed and measured in terms of Update latency, Update traffic for the domain management and Availability.

Results are presented in the comparison table using Percentage of changed DNS data per day.

Conclusion: In this paper, we demonstrated that the increasing use of public DNS systems, such as GoogleDNS and OpenDNS, fundamentally disrupts CDNs’ content distribution model. While we have confirmed that such systems indeed improve the DNS lookup times, and hence are beneficial for the vast majority of websites, we showed that this is not the case for the websites served on CDNs. Indeed, because end-users get redirected to a small number of heavily sub-optimal replicas closest to public DNS resolvers, not the end-users, significant problems arise.

Research Paper #3:

Research paper [4] addresses about a key problem in all name resolution protocols today is that no one protocol performs well across all network architectures. In addition, DNS, the most widespread solution today, depends on a static and connected network layer and faces significant challenges in dynamic wireless networks.

Technique enhanced: This paper introduces FERN(Federated Extensible Resolution of Names), the first framework designed to enable efficient name resolution across heterogeneous systems operating in dynamic or static networks. FERN organizes nodes into name resolution groups and allows each group to perform name resolution independently and in a manner best suited for that group. FERN arranges these name resolution groups into a hierarchy and allows these groups to communicate efficiently, discover each other’s presence, and resolve each other’s names.We demonstrate the flexibility and interoperability of FERN by deploying and evaluating it across heterogeneous environments, including a MANET, an infrastructure-based wireless network, and the Internet.

Contribution: Paper shows that FERN performs at least as well as DNS, and yet extends name resolution to networks in which DNS is inadequate. This paper presents FERN NRG rules and then builds FERN name resolution tree. Most importantly, it proofs correctness of proposed model.

Conclusion: FERN is novel in its ability to interface radically different name resolution architectures. By providing a unifying framework for these protocols, we have laid a foundation for interoperability between future name resolution protocols that are highly specialized for a particular network environment

A Comparative Study:

A paper that was published in 2012 tells us, Content Distribution Networks (CDNs) effectively exploit the Domain Name System (DNS) to redirect end-users to close-by content. Proposed solution in this paper is, quick DNS redirections. Systematically evaluate and quantify how the use of public DNS resolving services impacts Akamai’s content distribution model, the corresponding end-user service performance, and ISPs that host CDN edge servers. CDN-based DNS architecture, which can effectively function as both the current authoritative name servers and resolvers, coexist with the current DNS infrastructure. Paper demonstrates that increasing use of public DNS systems, such as GoogleDNS and OpenDNS, fundamentally disrupts CDNs’ content distribution model. Indeed, because end-users get redirected to a small number of heavily sub-optimal replicas closest to public DNS resolvers, not the end-users, significant problems arise.

Another Article tells us that, there are different problem in name resolution protocol performs well across all network architectures. FERN arranges these name resolution groups into a hierarchy and allows these groups to communicate efficiently, discover each other’s presence, and resolve each other’s names. FERN is novel in its ability to interface radically different name resolution architectures.

It just provides a unifying framework for these protocols and lays a foundation for interoperability between future name resolution protocols.

Another technique says that Round Robin DNS load balancing technique which allows a single domain name to be associated with several webserver IP addresses in a rotated order in a server cluster.

The performance of a load balancing system can be further enhanced if the right parameters are being taken into account in task or request distribution. Hence, the proposed algorithm in paper has indicated that by optimizing the load balancing scheme based on the right performance parameters, higher system efficiency can be achieved.

The Research Paper (original):

Research paper [1]is a study is based on two 24-hour packet traces collected from DNS root name server a.isi.eduand three other name servers that replicated various domains. Trace Collection - collection machine used a network interface tap (NIT) program to collect all TCP and UDP DNS packets, including non-transit local traffic. End to End Loss Rate - method to calculate end-to-end loss rate because our collection machine’s network interface does not count dropped DNS packets. Although the end to-end loss rate that we calculated was below 1%.Performance - DNS consumes at least twenty times more wide-area bandwidth than is strictly necessary. Classifying DNS errors, presents the classification scheme that devised, and discusses wide-area DNS performance using our scheme.

• Caching• Retransmission Algorithm• Resolver Algorithm• Name Server Algorithm• The Net Effect

How different bugs can classify? The name servers probably are not properly primed with alternate routes, do not detect server failure, do not back off their retransmission timeouts properly, probably don’t cache properly, and suffer from a form of looping because they do not forward queries properly.

How we can reduce bandwidth? There are different types of errors that cause of high usage of bandwidth. We can reduce these errors using different techniques. Seven classes of DNS implementation errors that identified.

DNS implementation.

DNS Replication: DNS replication is the process of coping records from one DNS server to another. Domain replicas do not run on individual servers, but that most servers replicate several domains.

Conclusion: In proposed article wide-area network traffic due to DNS will decrease as defective name servers and resolvers are replaced, assuming no vendor releases another devastating bug. As old implementations are corrected. We are currently writing such software for the Berkeley BIND name server. We hope to install this software into a root name server in the coming months.

References:

1. An Analysis of Wide-Area Name Server Traffic by B.Danzing, Obraczka, A. kumar, danzigtksc.edu, 1991.

2. Efficient Load Balancing for Bursty Demand in Web based Application Services via DomainNameServices by Lu Chin, Chong Eng Tan, M. Imran Bandan, University Malaysia Sarawak, 2010.

3. A CDN-based Domain Name System by Zhen Qinm Chunjing Xiao, Qiyaho Wang, Computer Communications 45 (2014) 11–20, 2014

4. FERN: A unifying framework for name resolution across heterogeneousarchitectures by spencer sevilla, priya Mahadevan, Computer Communications 56 (2015) 14–24, 2015.