Umm-e-Laila

Sir Syed University of Engineering and Technology Karachi, Pakistan

ulaila2002@gmail.com

Mohammad Murtaza Sir Syed University of Engineering and Technology

Karachi, Pakistan Engr.syed.murtaza@gmail.com

Mehjabeen Zahra Rizvi Sir Syed University of Engineering and Technology

Karachi, Pakistan Mehjabeenz89@gmail.com

Syed Zain Ali shah Sir Syed University of Engineering and Technology

Karachi, Pakistan Zains_shah@yahoo.com

Abstract—Internetwork Operating System (IOS) is most

widely used operating system on Internet and Corporate networks. Network professionals use IOS to configure networks and troubleshoot internetwork operations. Routers and switches are now come with built in Internetwork Operating System (IOS). These IOS provides command level interface to network engineers to troubleshoot and manage working of these devices .The most critical aspect of managing a good network is to keep all the critical devices up and running with minimum downtime. This paper provides comparative analysis of currently used well accepted practices for monitoring and debugging using IOS and with the advance optimization techniques based on Human Computer Interface (HCI) to reduce troubleshooting cycle. Both the techniques are compared using Key-stroke Level Model (KLM) model. Keywords- Key-Stroke Level Model, Internetwork Operating System, Human Computer Interface.

I. INTRODUCTION

Cisco System is an internetwork solution provider whose equipment and software products are mainly for construction of computer network. Equipment of Cisco System has large market share and the related design, configure skill and software usage become main stream of current network technology [1].

Network devices are at the core of any modern IP network. The design of TCP/IP requires intelligent nodes between networks that decide on a hop-by-hop basis how packets are forwarded from source to destination. If network devices fail or behave unexpectedly due to hardware or software malfunction, IOS troubleshooting steps will help in the diagnosis and resolution of issues. The ability to perform in-depth analysis and diagnostics on routers running Cisco IOS is therefore critical to ensure continuous operation of

any network. Cisco is among the top vendors providing routers and switches for data networks. Cisco devices use special type of operating system known as Cisco Systems’ Internetwork Operating System (IOS). IOS provides a command level interface to users to configure; monitor and trouble shoot network activities. If network devices fail or behave unexpectedly due to hardware or software malfunction, IOS troubleshooting steps will help in the diagnosis and resolution of issues. The ability to perform in-depth analysis and diagnostics on routers running Cisco IOS is therefore critical to ensure continuous operation of any network [2][3].

In this paper Keystroke-Level Model (KLM) is used which is proposed by Card, Moran, & Newell (1983), which predicts task execution time from a specified design and specific task scenario. In KLM, the sequence of keystroke-level actions the user must perform to accomplish a task, and then add up the times required by the actions [4].

A KLM consists of a stream of operators. There are five operators: P, K, H, R(t), and M. These operators are presented in Table 1[5][6].

TABLE 1 THE KLM OPERATORS WITH TIMES DETERMINED BY CARD

ET AL. (1983)

II. ADVANCED OUTPUT FILTERS Advanced filters have the capability to instantly find

required sections of Internetwork Operating System

Using Keystroke-Level Model to Analyze Advance IOS Optimization Techniques

2012 Fourth International Conference on Computational Intelligence, Communication Systems and Networks

978-0-7695-4821-0/12 $26.00 © 2012 IEEE

DOI 10.1109/CICSyN.2012.73

367

2012 Fourth International Conference on Computational Intelligence, Communication Systems and Networks

978-0-7695-4821-0/12 $26.00 © 2012 IEEE

DOI 10.1109/CICSyN.2012.73

367

configuration which is usually very large. In network malfunction situation, time is the most valuable commodity, the advantage of which can be taken by using the following Advanced Output Filtering Techniques.

Using Section Filter Using Regular Expressions

III. KLM COMPARISON FOR ADVANCED OUTPUT FILTERS- SECTION FILTER

Section filter is required to display particular section of Internetwork Operating System such as “Routing Protocol Section” as shown in Table 1 [7].

TABLE 1 ADVANCED OUTPUT FILTER – SECTION FILTER

Rack1R1#show running-config | section ^router router ospf 100 ispf network 10.10.0.98 0.0.0.0 area 10 network 10.10.10.13 0.0.0.0 area 10 router bgp 65535 no synchronization network 192.168.2.2 mask 255.255.255.0 neighbor 10.10.10.95 remote-as 65536 neighbor 10.10.10.95 update-source Loopback0 no auto-summary The “^” sign forces IOS to match router string which

occurs at the start of the line. Inside IOS there are actually different section, this example has shown the Routing Protocol section, it can be applied to other IOS section as well such as “SNMP”, “Access-List”.

KLM comparison of advanced output filter also includes a very considerable factor of mental operators as going through the full running configuration “show running-config” and stopping your view for particular sections and locating the required commands more specifically when it is related to the whole section takes a considerable time, by using section filter, complete section can be viewed at once eliminating the need to go through the full configuration and extracting the required information.

This comparison will have the following assumptions Hands start and end on mouse Router is in Privilege mode Tab is not used for auto-command completion Engineer knows how to apply the output filters Engineer is expert user

A. Case I: Advanced Output Filter – Full Running Configuration, without Using Section Filter

Task Execution Time Decide to use the command ; M 1.35 Move hands to keyboard; H 0.4 Point to Router CLI; P 1.1 Click on the Router CLI interface; BB 0.2 Type command ‘show running-config’ (n=19); nK

19x0.12=2.28

Press Enter Key; K 0.12 Search all lines of running configuration for 75x1.35=101.25

required output (for simplicity we assume that engineer will go through 75 lines), running configuration length depends upon the required parameters which have to be configured ; M Move hands to Mouse; H 0.4 Total Execution Time (sec) 107.10 sec

B. Case II: Advanced Output Filter – using Section Filter Task Execution Time Decide to use the command ; M 1.35 Move hands to keyboard; H 0.4 Point to Router CLI; P 1.1 Click on the Router CLI interface; BB 0.2 Type command (n=34); nK 34x0.12=3.6 Press Enter Key; K 0.12 Review only required lines (10 lines as shown in Table 6); M

10x1.35=13.5

Move hands to Mouse; H 0.4 Total Execution Time (sec) 20.67 sec

It can be concluded that Advanced Filter (Section Filter),

the execution time has been reduced to a great extent (from 107.10 to 20.67 sec) as shown in Figure 1.

Figure 1. KLM Comprasion of Advance output Filter-Section Filter

IV. KLM COMPARISON FOR ADVANCED OUTPUT FILTERS- USING REGULAR EXPRESSION(OSPF EXAMPLE)

A regular expression is entered as part of a command and is a pattern made up of symbols, letters, and numbers that represent an input string for matching (or sometimes not matching). Matching the string to the specified pattern is called pattern matching.

Pattern matching either succeeds or fails. If a regular expression can match two different parts of an input string, it will match the earliest part first [8].

Simple strings can be used to filter the outputs, much more can be achieved if full scope of the regular expressions are used [8].

While troubleshooting, routing protocols are the most difficult sections to troubleshoot, because of the complexity of algorithm and inside database architecture. Filtered routing protocol outputs (OSPF in this example), can definitely save a lot of time as shown in Table 2.

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TABLE 2 DETAILED OUTPUT OF OSPF WITHOUT REGULAR EXPRESSION Rack1R1#sh ip ospf neighbor detail Neighbor 131.1.13.3, interface address 131.1.13.3 In the area 0 via interface Serial2/0.13 Neighbor priority is 254, State is FULL, 6 state changes DR is 131.1.13.1 BDR is 131.1.13.3 Options is 0x52 LLS Options is 0x1 (LR) Dead timer due in 00:00:34 Neighbor is up for 00:00:13 Index 2/2, retransmission queue length 0, number of retransmission 1 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 1, maximum is 1 Last retransmission scan time is 0 msec, maximum is 0 msec Neighbor 131.1.12.2, interface address 131.1.12.2 In the area 0 via interface Serial2/0.12 Neighbor priority is 254, State is FULL, 6 state changes DR is 131.1.12.1 BDR is 131.1.12.2 Options is 0x52 LLS Options is 0x1 (LR) Dead timer due in 00:00:34 Neighbor is up for 00:11:35 Index 1/1, retransmission queue length 0, number of retransmission 1 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 1, maximum is 1 Last retransmission scan time is 0 msec, maximum is 0 msec

The information in which network engineer is usually interested in is OSPF adjacency, OSPF Interfaces, OSPF IP Addresses and OSPF Areas.

In this situation the use of regular expression is ideal, e.g including Neighbor and Area in filter will get required outputs (Table 3).

TABLE 3 CONCISE OSPF NEIGHBOR OUTPUT Rack1R1#sh ip ospf neighbor detail | include Neighbor|area Neighbor 131.1.13.3, interface address 131.1.13.3 In the area 0 via interface Serial2/0.13 Neighbor priority is 254, State is FULL, 8 state changes Neighbor is up for 00:01:07 Neighbor 131.1.12.2, interface address 131.1.12.2 In the area 0 via interface Serial2/0.12 Neighbor priority is 254, State is FULL, 9 state changes Neighbor is up for 00:12:29

Uptime of neighbor can be removed from the output by using the following expression as mentioned in Table 4.

TABLE 4 PERFECT FILTER DISPLAYING RELEVANT DETAILS ABOUT OSPF NEIGHBORS

Rack1R1#$neighbor detail | include Neighbor.* (interface |priority )) |area Neighbor 131.1.13.3, interface address 131.1.13.3 In the area 0 via interface Serial2/0.13 Neighbor priority is 254, State is FULL, 8 state changes Neighbor 131.1.12.2, interface address 131.1.12.2 In the area 0 via interface Serial2/0.12 Neighbor priority is 254, State is FULL, 9 state changes Regular Expressions up till now are considered as the

most powerful source to provide a concise and precise output.

KLM Comparison of Advanced Output Filter using Regular Expression considering – OSPF Example for the cases mentioned in Table 2 and Table 4.

This comparison will have the following assumptions Hands start and end on mouse Router is in Privilege mode Tab is not used for auto-command completion Engineer knows how to apply the output filters Engineer is expert user

A. Case I: Advanced Output Filter – without Regular Expressions as in Table 2

Task Execution Time Decide to use the command ; M 1.35 Move hands to keyboard; H 0.4 Point to Router CLI; P 1.1 Click on the Router CLI interface; BB 0.2 Type command ‘show ip ospf neighbor detail’ (n=28); nK

28x0.12=3.36

Press Enter Key; K 0.12 Search all lines of output as shown in Table; M

24x1.35=32.4

Move hands to Mouse; H 0.4 Total Execution Time (sec) 39.33 sec

B. Case II: Advanced Output Filter – using Regular Expressions as in Table 4

Task Execution Time Decide to use the command ; M 1.35 Move hands to keyboard; H 0.4 Point to Router CLI; P 1.1 Click on the Router CLI interface; BB 0.2 Type command (n=65); nK 65x0.12=7.8 Press Enter Key; K 0.12 Review only required lines (6 lines as shown in Table 9); M

6x1.35=8.1

Move hands to Mouse; H 0.4 Total Execution Time (sec) 19.47 sec The important factor to be noticed is the difference in

execution time, using Regular Expression from 39.33 sec to 19.4 sec as shown in Figure2.

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Figure 2 KLM Comparsion of Advance OutputFilter-Regular Expression

V. CONCLUSIONS By KLM analysis of execution time using advanced

filtering techniques, regular expressions, it can easily be concluded that with the growing complex networks requirements, the real-time need is to have effective time saving troubleshooting techniques that can provide desired results in less time.

Many vendors are now working on these techniques just to facilitate the engineers, reduces the total downtime in case of network failures as this is the most feasible way to achieve the rarest commodity in the world of Internetworks i.e. High Availability and Network Uptime.

REFERENCES

[1] Gang Zhang, Xiaomin He, Jian Yin and Qinling Zhong, "Construction of Cisco Virtual Lab Platform,", Third International Workshop on Education Technology and Computer Science, 2011, vol. 1, pp.213-215.

[2] Bjorn Frogner, PhD, Alexander B and Cannara, PhD.” Monitoring and Prediction of Network Performance”. NetPredict Inc., Menlo Park, California. April 1999.

[3] L. Bhuyan, Computer Science and Engineering, University of California. H. Wang, Department of Computer Science, Texas A&M University. Execution-Driven Simulation of IP Router Architectures.

[4] David Kieras,”Using the Key-Stroke Level Model to Estimate Execution Times”. University of Michigan, 2001

[5] Schulz,.T. “Evaluating mobile phones with the keystroke-level model and other desktop methods”, Master’s thesis, University of Oslo, Department of Informatics,Oslo, Norway, June 2008.

[6] Umm-e-Laila, Zain Ali Shah and Nadia Ishaque, “ Using Keystroke-Level Model for the Analysation of IOS Optimization Techniques”, International Conference on Internet Technology and Secured Transactions (ICITST 2011), Abu Dhabi, UAE, December 11-14, 2011, ISBN: 978-1-908320-00-1.

[7] Mack M. Coulibaly. Cisco IOS Releases: The Complete Reference. Cisco Press, 2000

[8] Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 T. Cisco Whitepaper

[9] William R. Parkhurst. Cisco BGP-4 Command and Configuration Handbook. Cisco Press, 2001

[10] Cisco IOS Terminal Services Configuration Guide, Release 12.2 [11] Cisco IOS Scripting with Tcl. Cisco Whitepaper

[12] Cisco Show Command Section Filter Release 12.3

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