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New Member

What is MTU size? why we define in Tunnel or Routing interface? Why not in Switching port?

IF I send 50 MB data in 10 Mbps link, rate of tranferring data is 1.28 MBps, is it a size of a data, If yes, then it means we can send only one packet in one second and that packet size is 1.28MB?


We define the Maximum

We define the Maximum Transmission Unit [MTU] on Tunnel/Routing interface so that packets greater that limit be fragmented or dropped before they are encapsulated.

Ethernet switch ports have MTU as well. Ethernet frame is data + L2 header incl. checksum and ranges from 64 bytes to 1518 bytes. GE ethernet supports jumbo packets of 9k bytes. So GE switch can support jumbo frames upto around 9,000 bytes.  If not configured to accept baby giants/jumbo even switch would drop larger frames.

Data doesn't ride on the link all alone. There are packet header overheads, inter-packet delays etc. at works. Larger the MTU, lower the overhead more the throughput. 10Mbps link can transfer 10Mega bits per seconds or 1.25 MB/sec. Also, MTU/packet size is not the only criteria for filling up the data pipe to its limits.


New Member

Hi vasanth_edw,like rais said

Hi vasanth_edw,

like rais said the MTU is not the only thing that can limit your throughput. Also TCP could limit your throughput see How is your RTT?

How many concurrent connection do you have?

I would like to offer you my help so contact me :) 


kind regards,


New Member

two concurrent connection

two concurrent connection

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