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Questions tagged [qos]

Quality-Of-Service (QoS) is the management of system resources, network or otherwise, to apply greater returns with minimal overhead, providing a measurable increase in performance.^1 ^2 ^3

Application QoS is related to thread management or Interprocess Communication (IPC) management as it relates to hardware and software resource access.

"In the field of computer networking and other packet-switched telecommunication networks, quality of service refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priorities to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow."

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How do we calculate the uptime of 24/7 website?

When companies come forward and claim 99.98%, how do they come to that number? Is that the only QoS parameter or are there any other useful and important parameters?
Srikar Doddi
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Qos(qWAVE API) for Multicast strange behavior

In Windows7 64bit OS, I use qWAVE api to set the DSCP value for outgoing packets with a normal traffic udp and it work fine. But , I 'm trying to do the same thing for a multicast traffic, but it looks strange!! The code logical flow like…
J2.NETe
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Maximum RabbitMQ Prefetch count

RabbitMQ 3.8.7 Erlang 23.0.2 I am using a Java client in order to configure my RabbitMQ queue. While trying to set up the Prefetch count using channel.basicQos API to 132,000, it seems in the "consumers" section in the RabbitMQ GUI it is always set…
Roy Leibovitz
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How to set QOS in CycloneDDS C++?

I am using CycloneDDS C++ version, trying to set following QOS to the writer DDS_HISTORY_KEEP_ALL, DDS_DURABILITY_TRANSIENT_LOCAL, DDS_RELIABILITY_RELIABLE I am trying to set Qos to data writer, in dds publisher dds::domain::DomainParticipant…
kingmihi
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Generate traffic and measure qos parameters in custom mininet topology using Ryu Controller

I'm working on tweaking and testing QoS capabilities in SDN. I've tried POX and Ryu controller and run some custom topologies in mininet. However I need help for generating traffic in mininet topology. It seems that there are iperf and D-ITG for…
AJAY
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MQTT wildcard subscriptions, backpressure and QOS

This is more of a generic question, however it might be handled differently in different clients or protocol versions or possibly even server versions. So I'm talking QOS level 2 subscription here. In which case packets are handled in order. And…
Christiaan Willemsen
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How to create specific Qos rules?

I have the topology that is represented in the image: I want the hosts 1 and 2 to have high priority with max bandwidth 8mbps and the host(server) 4 to receive packets at maximum bandwidth of 4mbps. Host 3 is irrelevant for now. I have achieved the…
Jonathan Baxevanidis
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How to set IO limit on RBD image (ceph qos settings)

From the ceph doc : librbd supports limiting per image IO, controlled by the following settings. Running the commands from the doc prints unknown options qos .... I haven't found anything on the web so far. Can anyone help me please?
aiqency
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SLURM QOS Preemption

I was trying to setup a preemption in my SLURM 19.05 cluster, but I could not figure out how to make preemption work like what I planned. Basically, I have two QOS. $ sacctmgr show qos format=name,priority,preempt Name Priority …
Woody
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PCA or Linear Discriminant Analysis ? Classification Problem in QoS

I'm working on a classification problem related to the marking of ip/tcp packet, the classes are Best Effort and Non Best Effort; I'm using Python language. I have selected these features: Protocol, Length of the packet, Port number used for source…
Davide Aureli
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MQTT higher QoS on subscriber

If I have a publisher sending a message to my MQTT broker with QoS 1 (at least once delivery) and a subscriber with QoS 2 (exactly once delivery), is it possible for the subscriber to still receive duplicate messages? My concern is that the…
wearebob
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Setting DSCP on a per-socket base

There are several examples about using iptable to set the DSCP field of the the IP packets. I am trying not to use iptables, but to set the DSCP field just on a few selected sockets. By reading man 7 ip, I found out that I can use something link int…
Ottavio Campana
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QoS for TCP connection made by a DLL

Our Windows app asks a 3rd party DLL to make a TCP connection to a server. We need to apply QoS parameters to this TCP connection, in order to reduce latency. Any ideas on how to do that? We're open both to suggestions that involve external tools,…
Lars D
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Communication between RTI Connext DDS and ROS2

In ROS2, Using qos_profile = rmw_qos_profile_system_default will use the default xml configuration from the installation directory of the DDS vendor, RTI CONNEXT in this case. Looking at this documentation from RTI, it means that the file…
Vishal Rawat
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GCD: does thread only has two types? main thread and background thread

Context: From my understanding, the Main DispatchQueue only dispatch tasks on Main Thread which is for UI mostly. However the Main Thread can also be used by non-main DispatchQueues. Apple has QOS to priorities the tasks: User Interactive: Work…
Tony Lin
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