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scp speed is too slow

Rosa Ladeira
Level 1
Level 1

Upgrading a NX 7K.

A scp copy of SO image from a server to NX7K bootflash is very very slow.

It took more than an hour to copy 30% of n7000-s1-dk9-npe.5.2.7.bin

Does anybory have a sugestion ?



5 Replies 5

Reza Sharifi
Hall of Fame
Hall of Fame

If you or some else has access to the box, use the USB.  Copy the image from your PC to the USB and than insert it into the 7k and copy the image. This way, is really fast.


This images are usually very large (compared to normal IOS device), but It should not take that long.

Are you sure that the path from the server to the NX is good?... I mean, if you try a FTP/HTTP transfer using the same link to another service it goes faster?


Network Faculty


There are multiple things that might impact the scp transfer. Some of the things that come to mind include:

- is it possible that there are fragmentation issues. Is there perhaps some link along the path with a small MTU that is causing the network devices to fragment (and possibly reassemble) the packets?

- is it possible that along the path that traffic is being tunneled/encapsulated and de-encapsulated which would impact throughput?

- are there problems that are leading to packet drop and re-transmission of packets?

- is it possible that there are more than one path being used to transmit the data and that some packets are delivered out of order and that re-ordering of the packets is leading to re-transmission of data?

- is it possible that something is causing the server to use a small packet size? Would a larger packet size be more efficient for transmission?





I have experiences the same issue with uploading code from a linux SCP server to ASR1002 router.  It does take a long time to copy the image to the flash.  I have other linux servers sitting on the same network as the ASR router and it takes less than 20 seconds to copy a 300MB file size.  With the ASR router, it takes about 30 minutes to copy the file from the scp server to the ASR flash.

I guess it is normal

Will White
Level 1
Level 1

You can tune CoPP:

policy-map type control-plane copp-system-policy

 class copp-ssh

  ! default is 500

  police pps 2000

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