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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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29 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
49 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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2answers
69 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
2k 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
70 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 ...
3
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1answer
219 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
326 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
5k 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
56 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
234 views

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
307 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
310 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
840 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
2k 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 ...
3
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1answer
719 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
1k 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
253 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
217 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
300 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
479 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
271 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
2k 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
9k 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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3answers
388 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
148 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
3k 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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0answers
419 views

Packet Loss between two similar VPN sites.

I have two sites connected via VPN both using Sonicwalls (1x NSA 2600 /w HA running SonicOS Enhanced 6.1.2.3-20n, and 1x TZ205 of unknown firmware. Both sites have 100/5 mb cable connection with ...
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1answer
1k 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 &...
2
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1answer
64 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: ...
3
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2answers
531 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 ...
1
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1answer
362 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
2k 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
124 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
159 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 ...
2
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1answer
145 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
169 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 ...
4
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2answers
281 views

Network latency and network bandwidth correlation

Today I was pinging random websites, and I decided to ping a website, from which I was downloading at the speed of 2mb/s, and the ping(latency) was 10 ms. My question is, if the answer from the ...
2
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1answer
145 views

Loosely speaking, at any given moment, how much of the internet is buffered?

When we ping a major web site, we're roughly measuring the delay between our device and the geographic location of the server that the site has chosen to send us to. It really could be anywhere. but ...
4
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1answer
2k views

Basic Link Aggregation scenario with high ping latency

Resume: I'm have a really basic network cenario with some new switches that I just bought. After configuring a LAG (without LACP) between them, I started to have ping losses and high latency. I also ...
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1answer
616 views

GNS3 Latency test

So I have a small topology ( 4 AS ), and I tested it on a real environment (College Lab) with Cisco routers (2000 series). The latency from one point to another was too high when I used GNS3, the ...
3
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1answer
198 views

Latency in P2P Circuit

I have one P2P Circuit from our HQ to a secondary office. the distance between them is approx 2kms. Earlier when the Circuit was delivered at that time we were having an RTT of 3-4ms. It is a 10Mbps ...
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2answers
735 views

POST duration over https vs ping time? [on hold]

I'm trying to get a first-order evaluation of how network latency / Round Trip Time (RTT) T, as characterized by ping time, will affect the duration of consecutive sequential POST requests over an ...
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1answer
4k views

Understanding Latency and Jitter [closed]

Analyzed 2 different internet connection. Details are as: Net-1: Download Speed: 2699 kbps (337.4 KB/sec transfer rate) Upload Speed: 4737 kbps (592.1 KB/sec transfer rate) Latency: 172 ms Jitter: ...
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2answers
1k views

Difference in latency between public and internal IP addresses

Should there be a difference in latency when accessing resources by their public IP address versus their private, internal IP address? And if there is, would (mis)configuration be to blame? My ...
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1answer
1k views

When should a transparent clock or boundary clock be used when designing a network supporting clock synchronization? [closed]

When designing a network incorporating IEEE-1588 (PTP), packet-delay variation (PDV) is a significant source of timing error. Both boundary clocks (network nodes which act as a slave clock to upstream ...
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2answers
542 views

Meaning of 2 Mbps

I read this article - https://rescomp.stanford.edu/~cheshire/rants/Latency.html I have a 2 Mbps private link. This means that I can transfer at the rate of 2*10^6 bits per second ~= 250*10^3 bytes per ...
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1answer
197 views

What factors affect propagation time for wired / wifi multicast messages? [closed]

I have a newbie question on multicast delivery times. In this article on clock synchronisation they claim that the propagation time on a local network is close to zero. What is the propagation time ...
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3answers
10k views

What causes packet loss when using full bandwidth from ISP?

We have a small, local ISP that is having some networking issues and I'm trying to understand the cause to better communicate with their network guys. I work with a number of companies with different ...
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1answer
1k views

Can I somehow increase the latency / response time of a server for testing?

I am looking to make some speed performance tests. Normally our server responds within ~25 ms or so, but, I would somehow like to make it answer with delay. So basicly I would like to make some ...