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BW Calculation

MUKUL JOSHI
Level 1
Level 1

Hi All,

How can i check the BW of a link that is newly comissioned from service provider.

Suppose i have upgraded bandwidth to 5 MB from a service provider and i want to check it using extended ping command from my router to PE end router.

What is the exact calculation (in terms of size ).....how much will be 5 MB can u please explain that calculation.

Best Regards

MJ

2 Accepted Solutions

Accepted Solutions

Hello Mukul.

you need to do a single test first to evaluate the round trip time. RTT

Roughly the bit rate of a single ping will be given by:

PING-Size * 8 bits/byte / RTT

So if you send 1000 ping of size 5000 bytes and you get an average RTT of 100 msec you can say that it counts like

5000*8 /0.1  =  400000 bps

And in this case to reach 5000000 bps you need 12 parallel sessions of extended pings with size 5000 bytes

Hope to help

Giuseppe

View solution in original post

about "so 5 MB is 5242880 bytes here right"

Note:

When used to describe Data Transfer Rate, bits/bytes are calculated as in the metric system

For example, 28.8 kilobits per second (kbps) is 28,800 bits per second

http://www.speedguide.net/articles/bits-bytes-and-bandwidth-reference-guide-115

The throughput of communications links is measured in bits per second (bit/s), kilobits per second (kbit/s), megabits per second (Mbit/s) and gigabits per second (Gbit/s). In this application, kilo, mega and giga are the standard S.I. prefixes indicating multiplication by 1,000 (kilo), 1,000,000 (mega), and 1,000,000,000 (giga).

http://en.wikipedia.org/wiki/Measuring_network_throughput

View solution in original post

16 Replies 16

Joseph W. Doherty
Hall of Fame
Hall of Fame

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Would be a "difficult" to verify 5 Mbps using pings.

What I do is use a non-TCP traffic generator.  Push, say, 6 Mbps toward the other side of the link.  See if 5 Mbps comes out.

Note - such testing can be adverse to other traffic unless you're using QoS and you can have the test traffic use only available bandwidth.  Good time to test is during a maintenance window.

Sandeep Choudhary
VIP Alumni
VIP Alumni

Hi Mukul,

Do you want to check, How much bandwidth is coming while ur provider promise for 5mb ?

Is it ??

If yes then:

Open this: http://www.speedtest.net/
Click on Begin test, it will show the DW and UP speed.

Run several speed tests, and evaluate the results. It is always a good idea to run at least three speed tests to cover any minor variations that may occur between tests. Take the average of all the tests, and compare it to the speeds that are guaranteed by your ISP to evaluate your test results.

Regards

singhaam007
Level 3
Level 3

Hi Mukul,

you can use Iperf, this is really easy . just with one command it will tell you network bandwidth.

http://www.techrepublic.com/blog/networking/use-iperf-for-quick-and-easy-network-tests/725

http://duntuk.com/how-use-install-and-use-iperf

hope this will help.

please rate if this helps.

thanks

MUKUL JOSHI
Level 1
Level 1

Hi All,

I am accessing this router remotely. I have to check the BW say a pipe of 5MB is given by SP which terminates at router gig interface.I can't take session of hosts devices to check this traffic otherwise it would be an easy task.

What i can do is send ping packets with some load and then can check this load in router's gig interface using command :-

sh int gig 0/0.

My question is how to calculate the size of those pings ? suppose i send a ping

ping source   size <1500>  repeat <1000>

Here i want to know what does size represent >> what is 1500 is it byte or bit or Kilobit or KB(byte)

Please advise

Best Regards

MJ

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

My question is how to calculate the size of those pings ? suppose i send a ping 

Here i want to know what does size represent >> what is 1500 is it byte or bit or Kilobit or KB(byte)

It's in bytes.

However, I don't recall when the size includes header's size.

Depending how exact you're trying to be, there's also framing overhead too.

Also unsure whether a Cisco ping sends every consecutive ping request physically back-to-back or whether there's a slight timing gap between requests.

Hi Joseph,

I have to open 4 to 6 remote sessions of this router and will try continous pings say about 5000 packets.

so 5 MB is 5242880 bytes here right !!

how much size should i  place i think 5000 will work ? i m not sure ....i m totally confused in this calculation?

Regards

MJ

Hello Mukul.

you need to do a single test first to evaluate the round trip time. RTT

Roughly the bit rate of a single ping will be given by:

PING-Size * 8 bits/byte / RTT

So if you send 1000 ping of size 5000 bytes and you get an average RTT of 100 msec you can say that it counts like

5000*8 /0.1  =  400000 bps

And in this case to reach 5000000 bps you need 12 parallel sessions of extended pings with size 5000 bytes

Hope to help

Giuseppe

Hi Giuseppe,

Thanks for the help.Now i got this concept.1 more question what is the max size that i can use in extended ping so as to reduce the no of session ...Is there any limit defined ?

Regards

MJ



about "so 5 MB is 5242880 bytes here right"

Note:

When used to describe Data Transfer Rate, bits/bytes are calculated as in the metric system

For example, 28.8 kilobits per second (kbps) is 28,800 bits per second

http://www.speedguide.net/articles/bits-bytes-and-bandwidth-reference-guide-115

The throughput of communications links is measured in bits per second (bit/s), kilobits per second (kbit/s), megabits per second (Mbit/s) and gigabits per second (Gbit/s). In this application, kilo, mega and giga are the standard S.I. prefixes indicating multiplication by 1,000 (kilo), 1,000,000 (mega), and 1,000,000,000 (giga).

http://en.wikipedia.org/wiki/Measuring_network_throughput

Hi Roberto,

Thanks Roberto.....Years old confusion is now clear .

Thanks for help.

Hi Mukul,

Here you are talking about 5 mbps line, can i know that existing line

is using for Internet access OR point to point connectivity ?

Secondly, what is PE Router ?

Thirdly, How to check bandwidth through Ping Load,

Plz explain with simple ping example with command

Hi Kuldeep,

It's a MPLS link to service provider.

PE ie provider edge router.

ping size .

Thanks Mukul for reply me

MUKUL JOSHI
Level 1
Level 1

Hi Giuseppe,

Thanks for the help.Now i got this concept.1 more question what is the max size that i can use in extended ping so as to reduce the no of session ...Is there any limit defined ?

Regards

MJ

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