# 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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### 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 ...
155 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 ...
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 ...
856 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 ...
330 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 ...
962 views

### POST duration over https vs ping time? [closed]

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 ...
5k 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: ...
2k 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 ...
2k 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 ...
704 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 ...
236 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 ...
11k 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 ...
2k 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 ...
919 views

### Cisco C891F-K9 ISR latency?

What is the multicast routing latency of Cisco C891F-K9 ISR? Please cite references for your answer. I think it's store-forward type and isn't one of the fastest models (given its price!). I've ...
26k views

### Initial estimated round trip time in the RTT formula

I was reading about Round Trip Time (RTT) and then I came across this formula EstimatedRTT = 0.9 * PreviousEstimatedRTT + 0.1 * Sample RTT What is the value of PreviousEstimatedRTT when it is ...
7k views

### What is the difference between data rate and latency?

Both attempt to measure the speed of a network. If data rate is the thing that is commonly measure in Mbps and latency is the thing that is measured in milliseconds, what are their similarities and ...
200 views

### Troubleshooting Slowness in Stocks Trading Applications [duplicate]

Hi Fellow Network Enthusiasts! I'm having a hard time troubleshooting a Real Time Stocks Trading Application. Here are the Steps I've done so far: Apparently, this is the only Real-Time Application ...
158 views

### bandwidth vs latency - question on stuart cheshire paper

I am trying to get my grips around bandwidth and latency. I have read Stuart Cheshire's essay, however, there are a couple of paragraphs that I cannot understand. Paraphrasing: Assume we are to ...
2k views

I need to measure the latency, jitter and packet-loss per link in a network, as opposed to end-to-end, e.g. like this: s1-eth0 <--> s2-eth0 (~ 20µs avg. latency, standard derivation 10µs, 57 % ...
5k views

### Can you reduce RTT by increasing the bandwidth on a link?

Does increasing the bandwidth on a link from, let's say, 1mb to 30mb reduce the RTT? I have found one answer saying no. Can someone please explain? Also, what are the best mechanisms to reduce RTT?
19k views

### Is daisy chaining switches increasing latency?

This is a general question not related to specific hardware. If we have the following configuration of daisy chained switches: internet ---- core network ----- switch 1 ----- switch 2 ----- switch 3 -...
2k views

### How to reduce latency on ASA 5510 WAN link?

I have a Cisco ASA 5510 connecting our office via 2Mbit/s Internet. When Internet link fills up, latency to a well-connected host on Internet goes from 5-8 ms to 500-800 ms. With ping, it may look ...
2k views

### measure one-way latency/jitter/packet-loss

I'm getting increased latency and StDev due to route congestion and packet loss, but the forward and reverse paths go over distinct networks (e.g. one being init7.net, the other one being he.net), so, ...
2k views

### Cisco - MtR alternatives

I trying to establish if there is a function within IOS somewhere that can provide the same results of MTR , i know it can be run from Juniper devices / *Nix & Windows devices. Goal is to ...
4k views

### Network Latency issues with Cisco AP

This question involves network latency as opposed to bandwidth. I have a small remote office with a single Cisco 881W Integrated Services Router (Ethernet WAN). The WAN modem is an AdTran NetVanta ...
3k views

I am having the same issue on my business connection 5Mbps as in another posting on this site. As soon as any computer starts a download the latency on the first hop past our DFG provided by our ISP (...
9k views

I just had an argument with a colleague of mine and thought I'd just reach out to the experts on this. Here's the scenario. We were using a website that measures your connection's speed. We tested ...
576 views

### Ultra-Fast Querying Using UDP Packets

I am implementing a system where one device on a network queries at a very high frequency (hundreds or thousands of queries per second) through sending a small UDP packet with 8 or so bytes of data. ...
59k views

### How to find the source of increased latency?

I've got monitoring setup on several devices in our office. The ping response time to small access switches is commonly 1-4ms... As of 3AM this morning, this has sky-rocketed to 300ms on average. ...
2k views

### Do faster segments of a network mean faster flow rate or lower latency?

This is another one of those hypothetical questions. I've been trying to figure out whether or not having a faster 'segment' of a network in between host A and host B will translate into a faster flow ...
3k views

### Accurate strategy for measuring point-to-point link performance?

I have a requirement to provide an accurate means to demonstrate line performance over a flat layer2 1Gb point-to-point Ethernet circuit, approx 100 miles apart that seemingly goes through a number of ...
264 views

### How fast can information travel through various media?

I'm working on compiling some information about network latency and designing tests to help our support folks troubleshoot problems. In order to do this, I need some basic information that I don't ...
386 views

### Recording latency between a controlled startpoint and uncontrolled endpoint

This might be a very basic troubleshooting question, but it's worth asking to make sure I'm testing things the correct way and interpreting results effectively. I have a controlled start point (a ...
4k views

### What is a reasonable latency for a L2 1G leased line between 2 sites, about 420km apart?

We need a dual gigabit connection to one of our customers and for the time being one of the lines has been brought online. The connection is between our DC and the customer's HQ, it's a L2 connection. ...
35k views

### What would cause high latency anytime there is traffic on WAN?

I have a network that has been experiencing slow internet speeds. After a great deal of troubleshooting, I have determined that any streaming content/downloads will cause the latency of WAN traffic to ...