[c-nsp] Cisco WAAS on DICMOM image transfer - Clarifications and recommendations

[Lee]

> a. With compression enabled, this would also improve the transfer time of
> images.

Only if the images aren't already compressed & it seems like they might be:
https://en.wikipedia.org/wiki/DICOM
  Pixel data can be compressed using a variety of standards, including
JPEG, Lossless JPEG, JPEG 2000, and Run-length encoding (RLE).

Regards,
Lee


On 12/27/16, Arun Kumar <narain.arun at gmail.com> wrote:
> Hi Netpros,
>
> We have been doing a POC with one of our healthcare customers who are using
> radiation imaging using DICOM/PACS standards. We are evaluating benefits of
> WAAS with respect to this specific application. Expectations from the
> customer are two-fold:
>
> a. Reduce the transfer time of images between application and endhost
> (radiation device)
>
> b. Optimize WAN bandwidth and perform consistently with varying network
> performance (latency and packet loss)
>
> Referring to this Cisco whitepaper on this topic:
> http://www-v6.cisco.com/c/dam/en/us/td/docs/solutions/Verticals/waasapno...
> <http://www-v6.cisco.com/c/dam/en/us/td/docs/solutions/Verticals/waasapnotes.pdf>
>
> POC is conducted with various features turned on in WAAS - 1. TFO only 2.
> TFO with LZ and LZ 3. TFO with DRE-adaptive
>
> Observations are below:
>
> 1. TFO only - Could not see any benefit compared to without WAAS turn on
>
> 2. TFO and LZ - Could see benefits shown in WAAS CM (18% between original
> and optimized traffic). But there is no improvement on the transfer time.
> Also the peak bandwidth remains the same on the WAN
>
> 3. TFO, DRE adaptive and LZ - See huge benefits due caching - both on
> bandwidth savings and transfer time
>
> Since customer would not typically re-transmit the same images multiple
> times in a day, caching is not applicable to customer network.
>
> Below are the clarifications and recommendations that we seek after the
> POC:
>
> a. With compression enabled, this would also improve the transfer time of
> images. We are not seeing it though. Can this be related to compression and
> decompression time taken by vWAAS which is off-setting the end to end WAN
> latency (50ms). Or any settings to be enabled to see transfer time
> improvements?
>
> b. For TFO to be effective, do we have to increase the buffer size and
> window size?
>
> c. Any recommendations on the WAAS settings specific to DICOM image
> transfer?
>
> Thanks in advance,
>
> Arun
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