ethernet switch difference

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"Research Paper Proposal #1: JAGWANI, Karan." 1

Research Proposal for

“Comparison of 10 Gigabit Port Ethernet Switches from Cisco, Force10 and

Foundry Networks with respect to Latency, Throughput and Frame Loss”

By

Karan R. Jagwani

“Karan Jagwani is a MS candidate in computer science at California State University, Chico,

CA 95929-0410 USA

03/08/2009




TABLE OF CONTENTS

1. Introduction ……………………………………….…………………… . 3

1.1 Purpose …………………………………………………….. 4

1.2 Problem Statement ……………………………………........ 4

2. Review of Literature …………………………………………………… 5

2.1 Packet Processing …………………………………………. 5

2.2 Test Methodologies ……………………………………….. 6

2.3 10 G vs. 1 G Multi-port Ethernet ………………………….. 6

2.4 Latency …………………………………………………….. 6

3. Problem Solution ………………………………………………………. 6

3.1 Sample Topology ………………………………………….. 7

3.2 Sample Test Methodology…………………………………. 8

4. Required Tools and Availability …………………………………….… 9

5. Schedule …………………………………………………………….… 9

References ……………………………………………………….…………10

Annotated Bibliography ……………………………………………..……. 10




1. Introduction:-

Internet consists of interconnecting devices like routers, switches, hubs and bridges. These

devices are used to process a packet and route the packet to the destination based on the

destination address on the packet. A packet is another name for „data‟ in the networking industry.

Data is transferred in the form of Ethernet frames. The main components of the Ethernet frame

format are the destination address, source address, checksum (A checksum is an error checking

field) and a payload field to store data. Frames when transferred can arrive in or out of the order

at the ingress (input) port of the switch. It is then the responsibility of a switch (Switch is the

Device under test) to route the frame in the proper direction through the egress (outgoing) port.

The performance of an Ethernet switch is very important. Ideally a switch should take very little

time to process and route a packet, and should not have any frame loss at any given point in time.

Currently, there are plenty of networking vendors in the marketplace who strive to achieve more

market share for their products. Each and every vendor is focused on gaining the customers‟

attention whose primary interest is in those products which provide the best performance. Hence

a vendor has to come up with a switch which provides maximum throughput, low latency and no

frame loss. The term latency refers to any of the several kinds of delays typically incurred in

Comparison of 10 Gigabit Port Ethernet Switches from

Cisco, Force 10 and Foundry Networks with respect to

Latency, Throughput and Frame Loss

Karan R. Jagwani, Master’s Student, California State University, Chico




processing of network data [7]. A so-called low latency network connection is one that generally

experiences small delay times, while a high latency connection generally suffers from long delays

[7]. Currently we have 10 gigabit (10G) switches which can route data at 10G speed. Just a few

years ago there were only 1 Gigabit port switches.

1.1 Purpose:-

The purpose of this paper is to study and compare the performance of Ethernet switches from

vendors such as Cisco, Force10 and Foundry networks. To evaluate the performance of the

switches from the vendors mentioned above, required performance tests will be performed on

different frame rates and various number of frame sizes on the testbed. „Testbed‟ is a term used

for a topology in the networking language. A sample network topology is explained in the

problem solution section.

All the mentioned vendors support 10 Gigabit switches which in turn assist to test the

performance of all the switches in one network topology. The major performance characteristics

being tested and compared in the research project are frame loss, latency, and throughput.

1.2 Problem Statement: -

The need to test the performance of an Ethernet switch is very much logical. The results of the

performance tests conducted on the switch are going to be very useful to the customers buying

the switches. This will also help companies working in the Communication industry to figure out

the performance difference between the switches from different vendors.




2. Review of Literature:-

Networking is a very vast field. There are millions of hosts communicating with each other in the

Internet community. A „Host‟ is a term used in place of a computer, and to connect all the hosts

there are devices such as switches and routers. A switch is fundamentally a communication

medium for data to travel. In the networking world the speed of the network depends upon the

performance of the switches. Hence there are so many networking companies working on the

production and performance of the switches. Currently , papers that are being published, have

shown performance of 1 Gigabit switch, and one which also reveals the difference between the

10 G switch and a Multiport 1 G switch. Some of the key concepts which will be used in the

paper are explained here in literature review section.

2.1 Packet Processing:-

IXIA, which is a company that produces traffic generators, presented a paper that explains how a

packet is being processed when it enters into a 10 Gigabit port. When a packet arrives on a 10GE

port, it is stored in ingress buffer memory while waiting to be processed by the packet processor

[6]. When the packet processor is ready, the packet header is copied into the packet processor

memory for processing [6]. This paper explains about traffic management inside a switch and is

very useful for the research that is being done.

2.2 Test Methodologies:-

The paper presented by IXIA also explains about the different test methodologies such as Layer 2

bidirectional throughput and latency. Layer 2 throughput, QoS (Quality of Service) and latency.

The test methodologies being used in the research are somewhat similar to the one used by the




IXIA. A sample test methodology for this research paper has been explained in the problem

solution.

2.3 10 G vs. Multi-port 1G Ethernet:-

A Research made on the performance between a 10 G Ethernet switch and a Multi-Port G

Ethernet switch concludes that the processing of a packet on many cores can result in more

resource consumption without much benefit [2]. The paper shows how a 10 G Ethernet switch

gives better performance then a 1 G Multiport Ethernet switch. Hence this paper is very useful

for the research being done on multiple 10 G switches.

2.4 Latency:-

One of the many performance characteristics is latency. Latency is defined as the time taken by a

frame to travel from source to destination. A paper presented on real time systems explains the

different latencies in the Ethernet world. Latencies are nothing but delays in the transmission of

the frames from a source to a destination. Different types of Latencies explained in this paper are

switch multiplexing delay, queuing delay, switch delay, and frame transferring delay [4].

3. Problem Solution:-

The solution being proposed in this paper covers performance testing, of characteristics such as

latency, throughput, frame loss and back to back frames on the Ethernet switches. The best way

to execute the test cases is to use the traffic generator (TC) with both transmitting and receiving

ports. Traffic generators are used to generate frames of different size and formats. In the sample

topology diagram shown in the figure 1 the sending port of the TC is connected to the receiving




port of the DUT and receiving port of the TC is connected to the sending port of the DUT. There

are number of protocols in the networking commerce and the Ethernet frame formats vary

according to the protocols being used in the test. Hence before initiating the execution of the test

cases, the DUT has to be configured with the required configuration. The basic configuration that

should be done on the DUT involves creation of a VLAN and then to assign all the participating

ports of the devices in that VLAN (Virtual Local Area Network). All the ports participating in

the communication have to be in one common VLAN to talk to each other. A local area network

(LAN) is a computer network covering a small physical area, like a home, office, or small group

of buildings, such as a school, or an airport [8]. A VLAN has the same attributes as a physical

LAN, but it allows for end stations to be grouped together even if they are not located on the

same network switch [8].

The challenging part in the proposed research is to figure out how to configure a switch and what

exact configuration needs to be done on the switch and on the traffic generator. The size and the

rate at which the frames are sent to the DUT should be different each time the test is performed.

This will help to get the behavior of the switch every time the frame rate is changed. As the

frame rate increases the load on the switch will increase and accordingly the performance of the

switch will change. These tests will be run multiple times each time the load on the switch will

be different to get the accurate results from the run.

The overhead of configuring the switch manually each time a test is performed can be reduced by

automating the configuration. Programs using scripting languages such as expect and tcl/tk will

be written to automate the configuration on the switch. The script will first login to the switch.

The program will be executed before every test run on the switch. This will take care of the all

the required configuration on the DUT. The other major challenge in this research is to read and

http://en.wikipedia.org/wiki/Computer_network

http://en.wikipedia.org/wiki/Local_area_network

http://en.wikipedia.org/wiki/Network_switch

http://en.wikipedia.org/wiki/Network_switch

http://en.wikipedia.org/wiki/Local_area_network

http://en.wikipedia.org/wiki/Computer_network




analyze the results received from the test run. Proper understanding of switching and routing

protocols is required to analyze the results of the switch. After the acquired results from the test

runs, the data will be collected and analyzed. This study will provide the performance results as

well as the reasons of the switch behavior.

3.1 Sample Topology:-

Figure 1

The topology shown in figure 1 consists of the switch which is the Device under Test. In the

topology the egress port of the TC is connected to the ingress of the DUT and egress of DUT is

going to ingress of the TC. During the execution of the test cases the TC will generate the frames

specific to the protocol being used in the test. The frames will then be received on the port B of

the DUT. After receiving the frame the DUT will process and forward the frame to the egress

port C. Through port C the frame will then travel to its destination location which is the port D in

this topology. Before starting the test, there has to be some configuration done on the switch and

also on the TC. While creating frames on the TC, the source and the destination address has to be

configured on the frame. A VLAN has to be created on the DUT and then all the participating

ports should be assigned to that VLAN. Also the specified protocol being used in the test has to




be configured on the switch. After the basic configuration the configuration specific to the test

methodology will follow.

3.2 Sample Test Methodology:-

A sample test method to determine the “frame loss rate” on the DUT is explained using the

topology diagram depicted in the previous section. This test requires sending the specific number

of frames at the specific rate from the egress port of the TC to the ingress port of the DUT. The

DUT then forwards the frames to the egress port which is connected to the ingress of the TC. The

frame loss is calculated by counting the frames transferred from the TC minus the number of

frames received on the ingress port of the TC. The formula for frame loss rate is as follows:

{(Number of frames sent – Number of frames received) * 100} / (Number of frames sent)

4. Required tools and availability:-

This project requires equipment like switches, 10G traffic generator, cables, connectors and a

frame capturing tool. The required devices are available from ABCD communications. The

Switches are the Device Under Test (DUT), and Traffic Generators will be used to generate and

send frames to the switches. Cables and connectors are used to connect the devices together.

Permission has been obtained from the company manager regarding the use of the above

mentioned equipment.




5. Schedule:-

The following table depicts the timeline for the research project.

Deliverable Date

Research Paper Proposal Initial Draft 03/01/2009

Revision of Research Paper Proposal 03/08/2009

Creating topologies 03/20/2009

Configuring and testing 04/02/2009

Research Paper First Draft 04/09/2009

Research Paper Second Draft 05/08/2009

Finalizing the results 05/10/2009

Final Submission of Research Paper 05/22/2009

References:-

[1] Marios Andreou., Aad van Moorsel. COTraSE: Connection Oriented Traceback in Switched Ethernet. The Fourth

International Conference on Information Assurance and Security, July 2008 IEEE.

[2] Hyun-Wook Jin, Yeon-Ji Yun, and Hye-Churn Jang. TCP/IP Performance Near I/O Bus Bandwidth on Multi-Core

Systems: 10-Gigabit Ethernet vs. Multi-Port Gigabit Ethernet. International Conference on Parallel Processing –

Workshops, August 2008 IEEE.

[3] Anh Pham Hoang, 1Jong Myung Rhee*, 1Se Mog Kim, and 2Dong Ho Lee. A Novel Approach for Fault – Tolerant

Ethernet Implementation. Fourth International Conference on Networked Computing and Advanced Information

Management , July 2008 IEEE.

[4] Jork Loeser, Hermann Haertig. Low-latency Hard Real-Time Communication over Switched Ethernet. Proceedings of

the 12th 16th Euromicro Conference on Real-Time Systems (ECRTS‟04), 2004 IEEE.




[5] Tony Field, Uli Harder and Peter Harrison. Network Traffic Behavior in Switched Ethernet Systems. Proceedings of the

10th IEEE Int.l Symp. on Modeling, Analysis, & Simulation of Computer & Telecommunications Systems

(MASCOTS.02), August 2002 IEEE.

[6] Ted Fornoles, Alireza Safari. 10-Gigabit Ethernet Switch Performance Testing, 2004 IXIA.

[7] http://compnetworking.about.com/od/speedtests/a/network_latency.htm

[8] http://en.wikipedia.org/wiki/

Annotated Bibliography:-

[B1] Ted Fornoles, Alireza Safari from IXIA “10-Gigabit Ethernet Switch Performance Testing”, 2004

The authors have given a detailed explanation about the 10-Gigabit Ethernet Local Area

Network (LAN) and what happens when a frame enters into a port of a switch. The authors

have also explained about the challenges we face while processing the packets.

[B2] Artur Barczyk, Jean-Pierre Duffey for the LHCb Collaboration “High Performance Gigabit Ethernet Switches

for DAQ systems” CERN, 1211 Geneva 3, Switzerland.

In this paper the authors are explaining about the commercially available Gigabit Ethernet

switches. And using these switches how to develop an efficient Local Area Network (LAN).

They have tested very high performance switches from different manufactures. The authors

say that they encountered very high loss of data when the data is being passed through the

switches under random traffic flows.

[B3] Srinidhi Varadarajan, Tzi-cker Chiueh “EtheReal: A Host-Transparent Real-Time Fast Ethernet Switch”

The authors in the paper are explaining about the architecture they made using Ethernet

switch EthReal. They claim that this switch support real time network applications. The

authors also explain how this EthReal switch uses a leaky bucket algorithm to route traffic.

http://compnetworking.about.com/od/speedtests/a/network_latency.htm


http://en.wikipedia.org/wiki/




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