Analyze The Lightweight Directory Access Protocol And NFS Protocol Family In Terms Of QoS And Overall Network Performance

At the completion of this unit students should be able to: 

1. Apply key architectures and technologies for networked applications 
2. Use standard techniques to deploy, secure, performance?tune and manage networked applications 
3. Compare  various  technologies  and  techniques  for  networked  application  management,  deployment  and  performance  tuning 
4. Analyse and justify the use of important networked application architectures and technologies. 
5. Utilise common and emerging types of middleware to design and manage networked applications
6. Analyse performance and deployment issues for networked applications 
7. Choose appropriate industry tools and techniques to manage networked applications 

Lightweight Directory Access Protocol

In network communication, the set of rules that governs the communication between the two devices is known as Protocol. The protocols define the standards by which one device should communicate with other efficiently.  As protocol is used everywhere whenever any type of communication takes place anywhere in the world. The data exchange at the physical level and the data exchange at the application level, all of the communications are managed by using different protocols. The standard model used all over the world is OSI layered model that has several protocols at different levels that is recognized at different layers of the model and should be recognized by the communicating parties. The Protocols are defined by some international organization and being followed and observed all over the world.

The protocols that are under investigation are Lightweight Directory Access Protocol And Nfs.

Lightweight Directory Access Protocol (Lightweight Directory Access Protocol ) includes set of open architecture protocols that are used to access the information that is stored centrally over the network. It is based on X.500 protocol standard that is being used for Directory Sharing, but it is quite less complex and used lesser resources as compared to the X.500. Due to this property, the Lightweight Directory Access Protocol is referred as “X.500 Lite”.

The information in X.500 is stored and organized in hierarchal model with the help of various directories. The information of directories can be stored in the manner similar to that of Network Information Service (NIS), which enables the person or user to access the resources based on their account over any machine which has Lightweight Directory Access Protocol enabled network. [1][2]

In several cases the Lightweight Directory Access Protocol is also used as Virtual Phone Directory that allows the users to efficiently access the information related to other users over the same network. But since Lightweight Directory Access Protocol is quite flexible as compared to the simple phone directory, as it is capable of connecting with other Lightweight Directory Access Protocol based servers all over the world. Hence it is also being used as the Virtual Phone directory that allows the users to contact and access their requirements for others users, work as kind of active virtual directory. With Lightweight Directory Access Protocol is quite common in the organizations for example like universities, private organization and government organizations and their departments.[3][4]

The Lightweight Directory Access Protocol is type of standard directory in hierarchal model for internet service around the world, allowing the users to access the content from multivendor directories. Technically the Lightweight Directory Access Protocol is protocol designed for running the directory services in order to modify and querying them over the TCP/IP network. Lightweight Directory Access Protocol version 3 that provide the clients the access to the hubs, routers and switches that has standard interface to rewrite the information for the directory.  The different vendors use the Lightweight Directory Access Protocol in order to access the devices and updating the required directories of the hardware. The standard for the Lightweight Directory Access Protocol Is Etf Rfc 3377. [4][5]

Lightweight Directory Access Protocol QoS

The measured performance of the loads generated due to the search requests over the Lightweight Directory Access Protocol Based Communication, The Performance of the Lightweight Directory Access Protocol is quite acceptable. The performance of the update operations to the directories with periodically querying the different segments over the networks with add requests, it is being observed that the processing time for add operations over the network dominates the time required to processing even at the low and higher server load times. This is not so in the search based query over the network and only performance lower in the situation when the server load is quite higher. This is because of the latency that is required by the write operation on the server that is on the heavy load that binds the resources for the certain period using the write operation. At the higher latency times the search latency is quite low, the searching and retrieving existing the required entry and then modifying the required resource then writing it back to the Lightweight Directory Access Protocol Directory.

Network File System (NFS) it is the distribution based file system protocol that was developed by Sun Microsystems in the year 1984. This protocol allows the user on client computer to access the files over the different network like local storage that is being accessed. He NFS is based on the Open Network Computing Remote Procedure Call (ONC RPC) systems. It is an open system standard that is being defined in the RFC that permits the developers to use or implement this protocol as needed or even modify it to suit its requirements. [6][7]

With Policy Enforcement Point (PEP) works as the network device or policy that all the network devices used and are capable of enforcing the various policies. This could be implemented on an of the nodes between the different communicating resources. Local Policy module is the one that is responsible for ensuring the policy being followed by driven by their admission control of any policy aware node.  The RSVP modules helps in requesting the LPM over the receipt of the RSVP message for the decision over it. The LPM helps in interacting with the PEP that contacts the PDP that request for the policy decision that sends the RSVP packets back to the receiver.

The PDP works as the logical entity that interprets the various policies that are related to the RSVP requests and based on the requests formulates the decisions. It decides the QoS and which node will be getting the QoS from where to where and so on. The PDP makes all the decisions based on polices decided by the administrative rules that have been laid down by the remote database such as the directory service of NFS. [6][7]

Lightweight Directory Access Protocol Network Performance

The PEP and PDP both can reside the machine but that ultimately lead to the consistency issues and scalability problems that happen over and over the network. Hence there are situations where there could be a single PDP and can have several PEP. This type of situation is useful in the network monitoring situations where all the network is observed and queries related to the QoS and traffic is being given prior approvals.

This enables the file servers even having no prior information of the client for the connectivity, even when there are no NFS based connections. For example, the NFS do not have any prior information to open any file since the information. The NFS lookup procedure that converts the file name to the file handle, this file handle is totally unique and displayed as the immutable identifier with the different i-node numbers that have the disk block address. The NFS performs the read procedure but the client need to specify the handle of file created and start the offset to read the files it encountered during the read operation. Such operation is generally used by end user with most OS providing the system calls to open the file and perform the read operation on them sequentially. The client service must maintain the required state operation in order to translate the NFS based operations over the network. The NFS all the performance is related to the RPC as the RPC is request and reply based protocol it is very poor over the wide area networks and have the higher speeds on faster LANs.[7][8]

The findings by the Wireshark captures shows that the protocol that work exactly as per the standard approach and all the paths and procedures in communication and using for the communicating with other devices is being followed.

The comparison with another classmate is done and here are the findings that we have discussed:

1. LDAP protocol works well in large network connected with high speed data networks
2. LDAP performance is poor in WAN networks
3. LDAP works well under normal and heavy load on servers if the operations are mainly of the read queries in case the of write queries, the performance degrades.
4. NFS is an open network protocol that can be customized as per the developer requirements
5. Works with PEP and PDP
6. There can be several PEP but single PDP is advised for optimal performance in single network

Conclusion

The conclusion that can be derived that the LDAP is quite efficient protocol that is used for directory listing services that can be used communicating with directories to which we have no prior information to be associated with it.

The NFS protocol also analyzed and observed that RPC protocol is being used over the TCP to perform the required task and operations over the network. The NFS works for said duration for file transfer and don’t require the FTP to transfer it from the file point or server.

References

[1]V. Koutsonikola and A. Vakali, "LDAP: framework, practices, and trends", IEEE Internet Computing, vol. 8, no. 5, pp. 66-72, 2004.

[2]Xin Wang, H. Schulzrinne, D. Kandlur and D. Verma, "Measurement and Analysis of LDAP Performance", IEEE/ACM Transactions on Networking, vol. 16, no. 1, pp. 232-243, 2008.

[3]M. Qadeer, M. Salim and M. Akhtar, "Profile Management and Authentication Using LDAP", 2009 International Conference on Computer Engineering and Technology, 2009.

[4]J. Cortes, "A brief introduction to LDAP and its future", IEEE Distributed Systems Online, vol. 5, no. 4, pp. 1-3, 2004.

[5]A. Batsakis and R. Burns, "NFS-CD: Write-Enabled Cooperative Caching in NFS", IEEE Transactions on Parallel and Distributed Systems, vol. 19, no. 3, pp. 323-333, 2008.

[6]R. Avila, P. Navaux, P. Lombard, A. Lebre and Y. Denneulin, "Performance Evaluation of a Prototype Distributed NFS Server", 16th Symposium on Computer Architecture and High Performance Computing.

[7]S. Guo, W. Yang and G. Wang, "NFS Protocol Performance Analysis and Improvement for Mobile Transparent Computing", 2013 IEEE 10th International Conference on High Performance Computing and Communications & 2013 IEEE International Conference on Embedded and Ubiquitous Computing, 2013.

[8]Yi Zhao, Rongfeng Tang, Jin Xiong and Jie Ma, "IncFS: An Integrated High-Performance Distributed File System Based on NFS", 2006 International Workshop on Networking, Architecture, and Storages (IWNAS'06).