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Questions tagged [bandwidth]

For questions about bandwidth where bandwidth is the amount of data that can be carried from one point to another in a given time period (usually a second). This tag is suitable when your question is about network congestion, speed, throughput and of course low bandwidth problems.

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35
votes
5answers
9k views

Why are Ethernet Standards written in the form of 10/100/1000? Why not just 1000?

I always have seen Ethernet Standards written in the form "low value/middle value/max value", and always wondered why. Won't a router just reproduce a lower speeds anything below its maximum if it's ...
23
votes
4answers
10k views

Does physical distance affect download speed?

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 ...
11
votes
2answers
22k views

Trying to find out exact TCP overhead cost

Corresponding this topic: https://stackoverflow.com/questions/3613989/what-of-traffic-is-network-overhead-on-top-of-http-s-requests The maximum segment size (which does not include the TCP or IP ...
11
votes
1answer
8k views

Traffic generation from Cisco IOS device to prove WAN circuit

In essence I want to know if there is any way that we can use extended ping or any other command variants to prove to the customer that that the circuit is able to achieve the minimum CIR. The CE ...
10
votes
3answers
19k views

What is the relationship between the bandwith on a wire and the frequency?

I am trying to learn networking (currently Link - Physical Layer); this is self-study. I am very confused about one particular thing: Suppose I want to send a data on the wire something like this: ...
10
votes
3answers
4k views

Why is my UDP broadcast wireless communication capped at 1 MB/s?

I am trying to implement Network Coding over a meshed network. Therefore I need to send packets to several destinations, this is way I am using Broadcast packets. But I can not understand why this is ...
9
votes
5answers
67k views

Bandwidth vs Throughput vs Data(bit) rate

I totally understand the difference between bandwidth and throughput. While bandwidth shows the maximum amount of data can be transmitted from a sender to a receiver, throughput is the actual amount ...
9
votes
1answer
647 views

What does bandwidth (digital) really mean?

Recently I came across a new kind of NIC capable of 400Gbps (It kind of blew my mind). Does it mean it's electric circuitry is capable of serializing/deserializing (SERDES) 400G bits per second of ...
9
votes
2answers
2k views

Switch-Assisted Load Balancing w/ Fault Tolerance

While studying for Cisco and Microsoft certifications I read a lot about NIC Teaming, Etherchannels and similar stuff. I know you can do static teaming in MS Windows Server or creating a port-...
8
votes
2answers
983 views

If TCP packets are pre acknowledged, what happens if packets are dropped?

On a VSat link with 800ms RTT latency and 10mbps bandwidth, that means 1MB bandwidth-delay product (data in flight). According to this useful (but closed) Q/A, packets are injected on both sides of ...
8
votes
2answers
510 views

Determining optimal bandwidth needs for the office

We're currently using the Cisco 1921/K9 router along with SG300 L3 switch and other L2 switches in the office environment. We're hooked up to a 10M fiber line for internet but not sure if we need that ...
7
votes
4answers
2k views

Can throughput exceed the bandwidth of a network

I took an introductory course to networking this semester and I was wondering: looking at things at the layer 4 level using TCP can the throughput on the network exceed its bandwidth? According to the ...
7
votes
2answers
321 views

What determines the degree of parallelism that can occur over a network?

I'm trying to learn more about how a network (both LAN and Internet) handles traffic, and one part of this is the question of parallelism. In the documentation for Speedtest.net, in describing how ...
7
votes
1answer
271 views

Throttling among Data Centers

In general, links among data centers are shared (having shared network infrastructure). Thus, I can't detect the available bandwidth in between two data centers that may vary every while and through ...
6
votes
4answers
50k views

How can I view bandwidth use by ip/host on a Cisco router?

My company has a 100mbps Internet connection and we have recently experienced extreme slowness when using the Internet (our provider's speedtest page indicated .25 Mbps download speed). When we ...
6
votes
2answers
5k views

Cisco Router (ISR4221) Throughput - Why so slow?

I'm looking for a new router for a new branch of hour company. I got experience with cisco L2 & L3 Switches but not that much with Routers. I was looking at the ISR4000 series, specifically the ...
6
votes
1answer
766 views

Bandwidth limit Cisco 3400 ME problem

I want to limit bandwidth (speed) of interface of Cisco 3400 ME switch. I did these: policy-map parent class class-default shape average 64000 And in gi0/2 interface I apply it: service-policy ...
6
votes
2answers
815 views

Why is internet speed called Bandwidth?

Why do we refer to our internet speeds as "bandwidth" with units of measurement like "10 Mbps"? As I understand it, Bandwidth is, as the name implies, the width of the frequency band, typically ...
6
votes
2answers
242 views

Merging multiple clients to one gigabit

Suppose I have a switch that supports Gigabit Connections and Auto Uplink. Also, suppose that I have 4 clients (A, B, C and D), each with 100Mbps NIC's connected to the Gigabit Switch such that the ...
6
votes
4answers
17k views

Tunnel interface bandwidth?

I am a little confused with the bandwidth setting on Tunnel interfaces between two Cisco devices. On each end I have Cisco routers with ten gig interfaces connected to my provider. I Have a tunnel ...
6
votes
1answer
820 views

Bandwidth calculation for protocol over different Data/Physical links

I am trying to calculate what the bandwidth utilisation for a specific protocol would be over different links. As a start, I have the utilisation for this protocol over Ethernet. E.g 70kbytes/sec, and ...
6
votes
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....
6
votes
2answers
5k views

Limit egress traffic 2960G

This is to support a user who has the requirement of simulating specific speeds for download/upload. We have configured a limit using service-policy that as successfully limiting upload speed (...
5
votes
5answers
283 views

How do two computers with different speeds communicate

This is one extremely basic and probably equally dumb question that I just couldn't ever find a definite answer to. Suppose we have 2 computers one that can transmit data at say 10 bits per second (A)...
5
votes
4answers
11k views

Cisco Router Limiting Bandwidth

I have a Cisco 2621XM connected straight to my ISP modem. I have a computer on the second interface of the router. Topology: ISP -> Modem -> Cisco Router -> Computer When I run a ...
5
votes
2answers
588 views

How does link aggregation work in reality?

I'm concerned that I'm misunderstanding how aggregators work in the scenario below: I have a project where I need 40 Gbps links between switches. My plan was to have my three switches use all four of ...
5
votes
3answers
188 views

Stupid question about bandwidth

An engineer and I were discussing that if our network has more network than actual needed would cause wasting bandwidth. For examples, if our company has only 200 devices are actually on a network, ...
5
votes
2answers
2k views

Speed benefits when switching from 1Gb copper LAN to Fiber Optic

We are trying calculate how will the network performance improve when we switch from 1Gb copper LAN to Fiber Optic. We have 5-20 people simultaneously working on a Server via the 1Gb LAN. There are ...
5
votes
2answers
862 views

Why are there 11 channels in WiFi communication instead of 3?

I'm a little confused about subdividing the WiFi radio band into 11 channels in the USA, 14 in Japan, and 13 in Europe, and to then use just 3 of them because of the overlapping problem. Why didn't ...
5
votes
2answers
233 views

Extended ACL bandwidth consumption

While preparing for CCNA exam, I found this recommendation in a book: Place extended ACLs as close as possible to the source of the packets that will be filtered. Filtering close to the source of ...
5
votes
2answers
18k views

Switch Fabric Capacity vs Forwarding Rate

What is the difference between Switch Fabric Capacity and Forwarding Rate of a switch? Also, what other types of speed or bandwidth are there for switching?
5
votes
1answer
351 views

Mechanisn for performing bandwidth accounting on Cisco routers

We're about to purchase a pair of Cisco 7201s for our edge routers, and some Juniper EX4200s for core. And I'm looking for implement bandwidth accounting for our hosted servers on this hardware (most ...
5
votes
1answer
182 views

Getting lot of unwanted broadcasts on my network

I am pretty new in Networking (noob), while I was monitoring my network using Wireshark, and I found that there is a lot of broadcasts happening all over the network, broadcast on Local network ...
5
votes
1answer
14k views

How To Limit a VLAN to a Specific Bandwidth Quota

I have a Cisco Router 1900 series and I would like to limit the bandwidth used by a subnet/subinterface. This subnet/subinterface (192.168.10.*) uses most of the bandwidth making it useless for other ...
5
votes
2answers
2k views

Cisco 3750-X Stack Bandwidth

I am currently managing a large datacenter spine-and-leaf topology. On our leafs, we use stacked 3750-X switches. I want to know how much bandwidth is currently going across the stack links (...
4
votes
7answers
985 views

Media Transfer rates......is using laser over fiber the fastest?

My simple understanding is that one of the advantages of going to fibre (light) is that you transfer things at a lot higher rate than a standard cable using the light frequency. Adjusting the light ...
4
votes
1answer
18k views

iperf: send specific volume?

I wanted to test some different test cases. I wanted to transmit 1MB, 10MB, 100MB, ..., 1GB, ... and measure bandwith with iperf. In the manual stands that I can use a combination of -l and -n ...
4
votes
1answer
311 views

Differences between Enterprise internet connections with the same nominal bandwidth

First of all, I am new to the forum and am unsure whether this is the right place to post my question. If this is not the right place, I would appreciate you letting me know the best website to ask ...
4
votes
1answer
1k views

How does bandwidth throttling work

I'm trying to understand the basic mechanics of how throttling works. Here are two scenarios: Scenario 1: A hotel offers a fast and slow connection option to its guests. Let's say the slow plan is ...
4
votes
3answers
5k views

QoS or more bandwidth?

Being in SP field I sometimes hear folks say "we do not need QoS, just let's make sure we have enough bandwidth". This has always been bothering me, because currently we have a network without any QoS ...
4
votes
1answer
1k views

limit bandwidth on a Cisco switch port,

Our company has a 3/.5 DSL connection. On this connection we have a VPN where the execs are able to access files on the network as well as VOIP. On this connection we also have our exchange email ...
4
votes
4answers
4k views

Delays and throughput

I have the following Questions regarding Delays and throughput Is transmission rate same as Bandwidth? What is throughput and while calculating throughput why do we consider transmission delay. ...
4
votes
1answer
1k views

Rate limiting specific IP adresses on Cisco 2960S and 2960X series

We are looking into rate limiting some specific IP addresses down to 5mbit for various bandwidth reasons. Is is possible to rate limit ingress and egress traffic for specific IP addressees on the ...
4
votes
2answers
1k views

Equal WAN bandwidth for all LAN devices using Sonicwall NSA 2400/2600

I have a Sonicwall NSA 2400 (soon to replace with NSA 2600). The LAN has a widely varying number of users/devices. Some days there are 10 people onsite, some days 75-100. I want to be able to ...
3
votes
4answers
793 views

What is the difference between Ethernet types, considering bandwidth?

Different types of Ethernet (standard Ethernet, Fast Ethernet, Gigabit Ethernet) have different speed of data transfer (10 Mbit, 100 Mbit, 1 Gbit). Why is that? On the physical layer, the speed of ...
3
votes
2answers
3k views

Time Division Multiplexing and Transmission Rate

According to my textbook, with TDM, each circuit gets all of the bandwidth periodically during brief intervals of time (that is, during slots). If we have a circuit switched network where each link ...
3
votes
3answers
220 views

Bandwidth is mimimum of the path?

Assume the Internet speed is 10 MBps, NIC is GigabitEthernet, PCI bus connecting to RAM is 133 MBps, disk IO is 70 MBps, and this server simply accepts files and stores them to disk and then returns ...
3
votes
2answers
669 views

increasing bandwidth between two Cisco switches?

2 Cisco 3750 switches are connected via port 22(Trunk). First switch consists of 3 VLANs(each vlan have 7 ports such as 1-7,8-14,15-21) and 2nd switch consists of 2 VLANs. what solution can i use to ...
3
votes
1answer
124 views

In 802.11 Wi-Fi, Is it better to be on the same channel as other networks instead of being in an overlapping channel?

While being on the same channel as another network is not ideal, is it better than being on a neighboring overlapping channel because 802.11 specification has methods for dealing with co-channel ...
3
votes
2answers
402 views

Spine and Leaf architecture with LACP

In a spine and leaf architecture with Link Aggregation between spine and leaves (active-active) like this: Do we have the same active-atcive link aggregation between the leaf and the server? Is the ...