Questions tagged [latency]

For questions about network latency. For instance: the propagation of your network traffic, where the transmission medium can be defect or the processing of packets by a network device has slowed down.

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47 views

Transmission and propagation delays

I am now working through book "Computer Networking - A Top Down Approach", and there is one question among others after the first chapter: "Consider two hosts, A and B, connected by a ...
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Will TCP packets smaller than the full bandwidth of its link travel at the same speed?

If I send 5bytes over a 1mbps connection will that travel faster than 500bytes. Or is the latency after propagation going to be constant since the packet is under 1mb? If you downvote because you ...
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How can the latency value be so low from Singapore to USA (~2ms)?

Here's the ping output from Singapore: 64 bytes from 8.8.8.8: icmp_seq=1 ttl=50 time=1.96 ms Singapore to 8.8.8.8 = ~2ms Another ping output: 64 bytes from 23.59.8.146: icmp_seq=81 ttl=44 time=66....
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129 views

Copper or Glass for Low Latency?

I'd like to preface the main content of this post with the following: I understand this question may be equally suited to the Physics Stack Exchange, and so I have posted on there as well, but maybe a ...
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1answer
62 views

TCP Bandwidth and delay guarantees

I was wondering if TCP can provide bandwidth and delay guarantees? Or does it have to implemented on the application layer?
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56 views

network slowness troubleshoot

I want some suggestion regarding our network issue: From our office location to our DC ==> it's ~270msc(office and DC lies in different countries). As, you can already see here latency is the major ...
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2answers
69 views

Best way to Fast Reconnect TCP with dynamic IP

I am aware of TCP Fast Open, all though, I'm pretty sure it doesn't apply when the IP of the server changes dynamically. Getting the IP of the server quickly isn't the problem. The problem is that I ...
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0answers
19 views

latency in the network layer and transport layer [duplicate]

We have several way to measure latency (ping command (ICMP packets), hping(TCP SYN), iperf..).What is the difference between measuring the latency in the network layer and measuring in the transport ...
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3answers
105 views

Estimate latency between two IP addresses

I would like to estimate what is the latency in sending a packet between two IP addresses. Let's assume that I have two IP addresses: ip1 and ip2. I can easily ping both ip1 and ip2, and the ping ...
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3answers
173 views

How to calculate the latency in vehicular network?

I need to calculate the delay in vehicular network V2V and V2I and I define it as the following: Where L [Bit] the length of data and the transmission rate where is the distance between vehicle i ...
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1answer
97 views

Response time of TCP congestion control

I would like to know about the overall latency of the TCP congestion control for adapting to varying network conditions. Specifically, my questions are: How fast can the system react after a change ...
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2answers
93 views

Delay, Packet length and transmission rate

Why does the delay in sending a packet from source to destination doesn't depend upon the transmission rate and the packet length? If we look at the delay formula then it is, L/R + D/V.
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Network latencies between opposite ends of the Earth

This is just out of curiosity. when I pinged domains such as bbc.co.uk and google.com (in California), I get latencies of around 5ms as below: 64 bytes from xx: icmp_seq=0 ttl=55 time=2.940 ms 64 ...
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1answer
30 views

Can clock synchronization ever be more than guesswork within a certain interval?

Assuming consistent spacial interference, e.g. The time for packet Z to get from point A to point B will always be constant. The time for packet Z to get from point B to point A will always be ...
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1answer
68 views

Estimating bandwidth requirements and productivity gain from traffic data

My small office has a 30Mbit/s internet connection, on which two or three people work. We could get twice the bandwidth at a substantial cost. I imagine a bandwidth upgrade would slightly improve ...
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1answer
982 views

How to Troubleshoot Network Latency Step by Step

Does anyone have an idea of how to troubleshoot high network latency step by step? For example, let's say we have a remote office. And all users are from that office are having high latency accessing ...
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2answers
2k views

Does bridging add delay?

If I use a bridge to perform traffic sniffing like man in the middle will the bridge add a delay? And what word should I use delay or latency?
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322 views

How to measure time a request takes between two machines?

I need to calculate the time it takes between: a request sent from a machine the request is received at another machine I can do it by logging, but the clocks at these 2 machines are possible have a ...
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2answers
3k views

Serialization and serialization times in 40G/10G and 100G/25G Ethernet

I've recently been involved in discussions about lowest-latency requirements for a Leaf/Spine (or CLOS) network to host an OpenStack platform. System architects are striving for the lowest possible ...
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1answer
116 views

Weird packet lost. Looking for some input

Like me start by saying I'm not an network expert but this situation got me scratching my head and you guys might be able to help. The infrastructure is 4 switches (Dell 2848). 2 For the LAN and 2 ...
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1answer
735 views

What is the relationship between throughput and latency

Looking at the structure of a TCP packet, such as discussed here: What is the internal structure of a mobile phone call packet/datagram?, this indicates that a TCP packet size is 192 bytes excluding ...
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2answers
2k views

What are the differences between TCP iRTT and ICMP Ping?

I’m attempting to estimate latency between my PC and any servers/clients it interacts with. I don’t want to use Ping for various reasons (requires both ends to allow it, would require additional ...
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4answers
20k views

What's the difference between `Latency` and `Round Trip Time`?

Golang community provide a HTTP/2 demo website to compare the performance between HTTP 1.1 and HTTP/2. We can choose different latency, e.g. 0s latency, 30 ms latency, 200ms latency. Is latency a ...
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2answers
73 views

are the RTTs additive?

By using the ping, I calculate the RTT between A and B. I calculate the RTT between A and C. I calculate the RTT between C and B. Is it possible to compare the RTT of topological link A->B with the ...
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2answers
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does the DSL distance really add more latency

I've been using dsl internet for quite a while and having a ping from Algeria to France of about 90 ms , after trying to ping some locations in Algeria , i am getting about 50 ms, ping to my gateway ...
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2answers
672 views

High Jitter and Data Loss on Cisco Meraki Z1

Our office is running a Cisco Meraki Z1 Security Appliance and recently (March 5th) the internet has been dropping out intermittently. The appliance remains online but the internet either doesn't work ...
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1answer
506 views

How to measure latency and udp-jitter from the end-server [closed]

Is there anyway to monitor a latency and jitter from SLA Router to EndClient(Linux Server). I have tried to use IP SLA with UDP Jitter but it didn't work. Diagram SLA-Router -------> Linux ...
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1answer
2k views

Is RTT the same as round-trip propagation time?

As far as I know: (1) Latency (τ) = transmission delay + propagation delay + queuing delay + processing delay (2) Round-trip time (RTT) is two times the latency (assuming the same latency both ways) ...
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3answers
4k views

Why can insufficient bandwidth reduce latency?

In this article, it is stated that latency does not affect bandwidth, but insufficient bandwidth can reduce latency. Can someone explain me the latter part of the statement? How would insufficient ...
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1answer
2k views

What is the latency of IP over Infiniband compare with 10Gbps fibre network?

What is the latency of IP over Infiniband compare with 10Gbps fibre network? 10Gbps network is something like a Solarflare low latency NIC card. How well does IP over IB perform not just throughput ...
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1answer
3k views

What is the value of EstimatedRTT at first time?

Although this question might be marked as duplicated! I'm asking again because other question's answers like this couldn't help me. So please consider the case and don't mark it as duplicate and ...
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2answers
411 views

Dynamically generate OSPF/BGP routes based on Internet latency

Scenario Three Offices with 2 ISPs each - utilizing static routing to the ISP. Each office has a VPN and leased point-to-point circuits connecting the offices in a ring. A VPN is also connecting the ...
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8answers
284 views

What are the concerns other than latency for network tuning?

Everywhere I keep finding "to achieve low latency" or "latency is of concern", do this! So, I don't really get what are the other concerns other than latency. I mean who doesn't want low latency? Or ...
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3answers
430 views

How can I determinte the reason of server-to-server latency in my network? [closed]

We have a proplem with server-to-server latency. How can I determine the reason for it? These servers are connected to different Cisco switches. Althought the reason for this problem might not be ...
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1answer
789 views

Using the value of RTT to estimate the latency

Generally speaking, we can calculate the packet delivery time using this formula, Wikipedia: Latency = Transmission delay + Propagation delay + queuing delay + processing delay My question is: Is it ...
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1answer
445 views

Latency of AOC vs passive DAC

Long time ago I heard from friend that on really short distance using optical links makes no much sense because comparing to passive connection optical interfaces introduce another layer of hardware ...
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3answers
3k views

How to measure the firewall latency?

I want to make a lab experiment to measure the firewall (a hardware) latency. This firewall can do Deep Packet Inspection (DPI) on some industrial protocols (you can consider as TCP payload inspection)...
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2answers
15k views

How to find out TCP/UDP latency of your network?

Many people often suggest you to use ping command to find out your network latency. But it is false and a myth you often find in articles on Internet. ICMP ping was never designed to find out latency ...
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728 views

Measure latency and other statistics by comparing PCAPs

I need to measure certain statistics, such as latency, packet delay, and jitter. Would it be possible to measure these statistics between 2 nodes by sniffing traffic on both ends and then comparing ...
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2answers
165 views

Cisco VLAN configurations with WAP - Poor performance

We've recently applied a new modification to our network config. Separating two SSIDs into a guest \ corporate split config. All of the VLAN and DHCP scopes are functioning in the way it was designed ...
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2answers
5k views

What's the difference among bandwidth, ping, ping rate and latency?

All these terms are quite related but I couldn't understand when to use which. I often hear that some networks have low bandwidth and high ping rate for online gaming. I thought they might be ...
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1answer
2k views

IPTV Cisco configuration for C2960

I have attached a network diagram explaining IPTV network , i have below queries to understand & configure IPTV . All ports on edge switches are configured as access ports in VLAN 101. On Core &...
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1answer
67 views

Setting policy on a Steelhead Mobile Controller (SMC) for “Latency-based location awareness”

When setting policy on an SMC with reference to Location Awareness - > Latency-based location awareness -> Optimize over adapters specified below if latency to SteelHead is more than: <#> ms: ...
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2answers
721 views

On a Layer 3 switch, what part does the CPU play in forwarding packets?

I am a Systems Administrator at a small firm. We are latency sensitive. When forwarding packets, what protocols use the CPU and which use the ASICs? We have mostly Arista 7124's (for the most latency ...
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1answer
467 views

Website not loading/very slow only on a client's netwok [closed]

I really need some help to explain following two scenarios as I only have little network troubleshooting skills. I am supposed to go to these clients and give a valid reason for these issues. The ...
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2answers
4k views

Switch Buffer Sizing

What is the relationship between a switches buffer size and the effect it has on latency? I am aware of the bufferbloat issue and understand that buffers that are too large in networks of slower BW (i....
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2answers
157 views

Random latency on a wireless LAN

I'm facing a weird situation. Office LAN configuration is : A Netgear router as the main router An Ubuntu PC with UniFi controller software 10 UniFi APs At anytime, the latency between a computer ...
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1answer
222 views

How much influence does multicast and IPv6 have on latency?

I am looking for a fast and a diverse library for my game engine network. I have searched for a while, and I decided to use a simple one because of being fast to understand. I saw there are better ...
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1answer
163 views

Estimating latency via distance and betweenness

I want to compute the relationship between delay (latency) with distance and betweenness. More specifically, if I know (let's assume) that the distance and betweenness values for two different ...
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2answers
194 views

Transmission Rate in terms of distance

If the transmission rate of a physical link, such as ethernet cable, between a sender and receiver is set to be 100Mbps, does it imply that the receiver will receive 100Mb of data in each second? What ...