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Questions related to Network Administration
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Can someone explain me what are the common layer 3 problems that happen in a network? specially in SOHO environment if possible.
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If you can provide references if possible, that will be a great help.
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David Lide Yeah but what are the protocols used to read those data. For an example FLPs are used to do auto negotiation. Like wise how are the other things are read or managed by the NIC?
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I am trying to extract precip and temp data for an area located in Asia from CORDEX RCM data set in R programming language. The netcdf files are in the rotated-pole coordinate system (0 deg E, 0 deg N)  and I need to transform this RP to WGS 84 , so how can I do this in R? I have gone through the manual and different scripts posted in stack-overflow, but have not found a script that actually transform the projection.
If anyone knows how to do this, please consider providing the scripts. Your help will be highly revered.
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Hi! Just stumbled upon this thread while looking for other related issue. Hope this helps:
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Dear Experts
I have a university project to build a soft load balancer in SDN/OpenFlow (Linux) environment. I'm thinking to use mininet as OpenFlow network simulation. Can you help me to find if and how we can accomplish the below requirements with mininet or should I consider some other simulator?
1. Customized topology with "4 servers and 48 client nodes" "The interface shall contain classification of client nodes having different requirements of bandwidth at different times. This shall be 4 periods with different bandwidth distribution."
2. Which OpenFlow controller can fulfill these requirements? "Measure Performance and Utilization Statistics" a. Throughput b. Delay c. Utilization d. Load Distribution e. Response time
This project requires designing a network load balancer with OpenFlow that will provide GUI based interface to the network administrators. The data from the GUI will be fed to the load balancing controller that will coordinate with network nodes to manage the routes to the server.
Please answer whichever part of the question you can guide me for.
Thanks in advance.
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Hi Aleksandar
Thank you for you reply.
I’m not bound to use some specific flavour/version on linux. It’s optional.
The core functional requirements of package are to:
1. Customize OpenFlow Based Controller ODL or FDL with any simulator
2. Develop GUI Interface to configure the controller
3. Customize a Network Topology
4. Measure Performance and Utilization Statistics
a. Throughput
b. Delay
c. Utilization
d. Load Distribution
e. Response time
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Suppose Info-Tech is a company having large scale computer network consisting of more than 100 routers in operation. The company has hired you as a network administrator to maintain and troubleshoot its network. In this network, adding and removing hosts is normal and number of hosts is expected to grow in future. In view of this, the network needs fast convergence with the help of suitable dynamic routing protocol.
As a network administrator, in your opinion, which dynamic routing protocol from the following will be most appropriate for this organization’s network? Justify with any two solid reasons.
1. Distance Vector Routing Protocol?
2. Link State Routing Protocol
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Zahid, I believe this article addresses the tradeoffs really well:
Distance vector protocols are simpler to understand and simpler to configure, but they are limited in the size of networks they will accommodate and the take longer to converge, compared with link state.
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Any papers on the role of Intranets in managing satellite/remote campuses?
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Check the following reference Please.. it might's assist you in your question …
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I am trying to implement bitcloud zigbee stack form my avr-atmega256rfr2 custom board.I downloaded the stack from  http://www.atmel.com/tools/BITCLOUD-ZIGBEEPRO.aspx .After reading the documentations of bitcloud provided with SDK,I changed the configuartion file of WSNdemo application with necessary parameters.Then I programmed one coordinator and one router.Each one having different CS_UID.Then I used WSN monitor to view the nodes.At this time I can see only the coordinator no routers.Any help on this particular area will be appreciated.
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I am a student and I am following a course on Productivity and efficiency analysis, we are now focus on Network DEA, but I can't make an extimation on how many Netwrok DEA Models exist, and which are them.
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Many thanks to both of you! I've really appreciated your helps!
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i need some protocols used in other technologies and that can be used on ioT to guarantee user privacy.
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Thank for these answers it is useful 
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I need a reliable and referable ranking (for example, a ranking published by Gartner research center) of Network Management Systems. Can any body help please?
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Hi,
Are you talking about prioritizing Network Management Functions, or ranking industrial products (NMS)?
In the latter case, I am not aware of such studies, but maybe you might be willing having a look at the results of the European Network of Excellence Flamingo focusing on Network and Service Management.
Some good piece of information is available.
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I am trying to model a hybrid network. I have finished literature review and for now know how exactly I want to do network management. But I am new with NS3 and need some help with it. So I need simulations or codes of already published thesis related to C_RAN and SDN, so that I can re-do them and have an idea. All suggestions would be helpful
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LENA project provided by CTTC
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Recently, I am using the Forcite module implemented in Materials Studio, but every time I run with the remote server, it fails immediately.
The remote server is CentOS7.0 with Intel E5 v3 2697. I have installed MS in the server, and I run from the Windows in my workstation.
But if I run that by using the worksstation, it goes well and succeeds.
Once run in parallel in remote linux server, the job fails.
I have checked the file 'std.err', it said this:
      "sh: error while loading shared libraries: libdl.so.2: cannot open shared          object file: No such file or directory"
So I locate the libdl.so.2 in CentOS7, it exist in /usr/lib:
     /usr/lib/libdl.so.2
     /usr/lib64/libdl.so.2
and
             lrwxrwxrwx. 1 root root 13 May 8 2015 libdl.so.2 -> libdl-2.17.so
I have googled this error, still don‘t know how to fix this bug.
I hope someone can give me a hand here.
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I have solved this problem.
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Different solutions have been employed but packet loss ratio is very high. The best up till now has been wire-shark. Kindly guide as to how we can increase the capture ratio and what software are commonly used in the community for this purpose.
Thanks in advance for your help.
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Packet losses can happen due to your physical medium channel (copper cable, radio link, optical fiber), network equipments malfunction/configuration, network topology or QOS, or be related with one or both of your network endpoints (which includes network stack, protocols, etc). And these packets are really losses, which means that the packet information get lost at some point and the receiver never receives it.
But you may be experiencing another type of "packet loss" which can be caused by wireshark (or other capturing tool) itself and it is usually called "dropped packets". This type of loss is shown in the wireshark status bar, alongside with the number of packets captured, displayed and marked statistics. PLEASE NOTE that this information is only displayed if Wireshark was unable to capture all packets [refer to https://www.wireshark.org/docs/wsug_html_chunked/ChUseStatusbarSection.html ], which allows you to immediately infer if this is your situation. Please note also that this metric IS NOT SAVED in your pcapng files; you can see it - if it occurs - while capturing or even after you stop the capture process but still displaying the capture in the wireshark; even if you save that capture, once you close it, you will not see this metric again.
This type of packet loss relates with the performance of the capturing system, usually due to your hard drive read/write rate and overall system load. What happens in this situation is that wireshark was able to detect one or more packets in the capture network interface, but due to the low performance, it could not save the related packet information, so the capture algorithm chooses to drop that packet(s). There are some tricks you can follow to minimize (not avoid!) the low performance impact, which are explained in the "optimized Wireshark settings" section, https://wiki.wireshark.org/Performance . Note also, that the operating system has an important role in the performance; some time ago, while facing some problems related to this, I discover that the number of packets dropped by wireshark on Linux was (much!) less while capturing with Wireshark on Windows - what was not really a surprise for me. Notice that the performance issue can also happen with other software tools. I will assume that you are not generating network traffic in the same capture system, because this negatively influences the performance too.
If you are dealing with optical fiber links, I advise you to - if possible - forget wireshark or similar software tools and use instead a dedicated network performance measure equipment. These kind of equipments usually have dedicated high performance hardware, like FPGAs, that will allow you to generate all kind of network traffic and get almost all measures and statistics you may desire or need.
From my personal experience, considering a I7 Quad Processor, with 16GB RAM but a mechanical 5400rpm or 7200rpm HDD, when considering a large number of packets, from time to time - say 1 in 10/15 times - I was facing dropped packets even on a 1Gbps ethernet link. The problem was more notorious as the number of packets increases (typically for < 1 million packets it were dropped less than 1k packets but for 9 M, the number of dropped packets increases to 3M easily!). Although I successfully reduced the number of packets dropped, I could not avoid the problem because from time to time, I still get some dropped packets, which do not allow me to have 100% confidence in my measures.
Since at the beginning I have no access to a dedicated Network Performance measure hardware, I developed a simple measure system based on FPGA that allow me to despite this problem and prove the correct system function.
I hope that this information can help you.
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Hi Dear all,
I am trying to implement the Bound Handling techniques for a particle velocity and position. I am using Deterministic Back and Nearest technique for velocity and position respectively. I have implemented these two techniques in two different methods (in the program). I am getting slightly different results from these methods. I am not sure which one is the right method. Please let me comment. If both of the following methods are incorrect then please let me suggest the correct way of implementation.
Method-1
       for (i = 1 to SWARM_SIZE)
          {
           for (j=1 to PROBLEM_SIZE)
             {
                Compute V(t+1) using standard PSO velocity equation
                If (V(t+1) < V_min || V(t+1) > V_max)
                                 V(t+1) = - 0.5 * V(t+1) // this deterministic back technique
              Compute X(t+1) using standard PSO position equation
                If (X(t+1) < X_min)
                                X(t+1) = X_min
                Else if (X(t+1) > X_max)
                                X(t+1) = X_max
         }
}
Method-2
       for (i = 1 to SWARM_SIZE)
          {
           for (j=1 to PROBLEM_SIZE)
             {
                Compute V(t+1) using standard PSO velocity equation
               Compute X(t+1) using standard PSO position equation
                If (X(t+1) < X_min)
                       {
                                X(t+1) = X_min
                                 V(t+1) = - 0.5 * V(t+1) // this deterministic back technique
                          }
                   Else if (X(t+1) > X_max
                                {
                                    X(t+1) = X_max
                                    V(t+1) = - 0.5 * V(t+1) // this deterministic back technique
                            }
         }
}
Many thanks
Best regards,
M Khan
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I suggest to use the first techniques.
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Experts in network security and networks
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Please refer to this study. It may help you to sort out the problem
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Does MTML allow understanding on effect of variable (e.g influence, power etc) towards network formation (antecedent) or effect of network (e.g structure, density,centrality etc) towards variable (e.g image, loyalty etc). thanks
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sorry I do not have the expertise to answer this question.
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I am looking for opinions to include in my studies...
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Based on my experience as a network research-based student, configuring the network layer quite difficult particularly for the beginners that are practicing "trial and error" practices. If the configuration success, it is a luck for them. However, if it is not success, they will search for another methods or commands (mostly ask for Google's help).
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I am looking for algorithms that can automatically estimate the bandwidth of a signal (or even multiple signal) without knowing the modulation and signal type.
Please tell the reference related to method if possible.
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Just refer to the classical MUSIC algorithm and apply it in your case of superimposed signals with different frequencies.
Find attached the MUSIC algorithm.
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I want study on communication complexity of interconnection network. so please share the published paper or materials about this.
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Go to my page and read my paper. you will get the different parameters which are very much related to interconnection networks.
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Suppose we have a set of API hosted on a local server. I only want legal remote programs to invoke those APIs. If the remote program is, let's say the original program that I uploaded to the remote machine, then I allow the invoke. If the remote program is a version tampered by the attacker, then I disallow it. How can I bind the program's identity to the function invocation to determine whether the remote program is not tampered?
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Remote attestation based on trusted computing supports detecting changes of the remote software.
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Hi all
How to forward packets received form neighbor motes ?,
consider scenario
1-----------2------------3
mote 1 and 3 are not in their transmission range,
whenever mote 1 send packet, mote 2 captures it and the stores for few time, and later sends to mote 3 , i.e. mote 3 feels that the packets are coming directly from mote 1
------------------------------------------------------
I am working on wormhole attack on RPL IoT,
guidance regarding for coding above (mote 2) will helpful
where should i focus either on contikimac or cc2420 radio chip for coding above mote ?
Any one has experience on creation of wormhole attack on any simulator ? then please guide regarding the same
Thanks in Advance
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If you want to send this kind of messages at MAC level could be difficult, at least you can do it, keeping the original address on the network layer address or just modifying the contikimac, to keep the original source address and modifying the rest of the message, then, when your mote 3 receives the packet and decipher it, the remaining information at MAC level will be from the mote 1 instead of mote 2.
Regards,
Francisco
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Is this possible with Libvirt or there exists some other means?
NOTE: This can be done within the Guests themselves but the interest here is to get the stat externally at the host. I have seen an approach for KVM but haven't seen anything for XEN servers.
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Hello Olumuyiwa Emmanuel Ibidunmoye ,
I am not sure whether this would be helpful or not.
How about this command ?
xm vcpu-list
-Srikrishnan
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What types of testing should be used when we need to test cloud and its services.
I am referring to testing cloud not "CLOUD TESTING"
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Han Ping Fung has explained almost everything. I do agree.
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I am planing to do some experiments in a cloud environment to see how specific methods defend against cloud DDOS attacks. To build a cloud environment, I need to know which cloud simulator would be suitable for such work.
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Hello there if you have perform some experiment with DDoS in cloud. Can u help me with materials as I am new to this and have to do my Mtech thesis on the same It will be appreciating if you can help me through it as I dont know how to Implement DDoS on cloud
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Penetration testing is a very difficult and complex task in network security testing. How can we automate this process? Which tools or demo and test versions are available?
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Penetration testing tools are used to automate several tasks in order to improve testing performance and identify those security issues, which are harder to discover with manual testing analysis approaches. There are two general types of penetration testing tools: static and dynamic analysis. These both kind of tools are used with veracode to determine security susceptibilities. In addition, veracode’s binary scanning methodology is more accurate and result oriented that controls the false positive. The veracode can help small to large types of organization for handling the security risk. The penetration testing should be set in such a way to control the weak and vulnerable points of environment within the organization. The goal of incorporating penetration testing is the only way to secure the cyber-attacks and hacking.
So, the appropriate option is to make suitable change with Firewall and incorporate the penetration test features that can automate the testing process for security enhancement. The second option for automation of penetration testing is to employ with intrusion detection system (IDS) for handling the false positive. But I think Veracode-Platform does this function automatically.