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New Member

tcp max-bandwidth-mbps , min-available-bandwidth-mbps and round-trip-time-ms

Hi


How to Calculate / Estimate / even test  the needed values for tcp max-bandwidth-mbps ,  min-available-bandwidth-mbps and round-trip-time-ms when configuring  FCIP connection between different sites

between MDS Cisco 9513 and 9216 i Switches

I have a speed upgraded to 4 times the old speed

thats for Replication

and how to test latency if possible

Kindly advise

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4 REPLIES
New Member

tcp max-bandwidth-mbps , min-available-bandwidth-mbps and round-

Sami,

To measure the RTT use the command, "ips measure-rtt interface gigabitethernet ", this will send a ping issued from the FCIP engine on the linecard to the destination IP address, which should be the other end of the FCIP tunnel.  If your RTT changes slightly due to network issues, don't worry, the MDS continuously updates the RTT in real-time.  The value is initially used for when the fcip tunnel first comes up and then the automated measurements take over.

To determining min/max bandwidth I would recommend working with your WAN team to determine what your expected bandwidth should be as they may be limiting you  or guarateeing you with QOS.  For example use the following questions with them:

What is the maximum amount of bandwith that is being allocated to FCIP traffic by the LAN/WAN? 

For the min value, asking "What is the minimum amount of bandwidth that is guarenteed by the LAN/WAN?"

You can use various methods to test the speed of the FCIP tunnels such as the MDS CLI "san-ext-tuner" or use your arrays with valid data (the luns could be full of zeroes which would give you false stats due to them being compressed). You could either fill the luns with valid data or disable compression.  Then watch the stats on the GigE ports (post compression stats) or the FCIP tunnels (pre-compression stats).

-Seth

New Member

tcp max-bandwidth-mbps , min-available-bandwidth-mbps and round-

Thanks Setmason

yes RTT 2173

i found that earlier

can you tell more about MDS CLI "san-ext-tuner"

will that tool test speed or used to set min and max  values ?

New Member

tcp max-bandwidth-mbps , min-available-bandwidth-mbps and round-

Sami,

SET is basically a load generator, like IOMeter but for FCIP traffic, it creates a virtual initator and target and generates a stream of reads or writes.  You would then use other tools to measure at various locations.  SET does provide some basic performance numbers, but I would recommend using other CLI or DCNM/DeviceManager based tools to see traffic.

-Seth

New Member

tcp max-bandwidth-mbps , min-available-bandwidth-mbps and round-

ok thanks setmason

I will look for some ways to measure and determine the best values as min and max

will check again with the network team if they can help me with alo

Regards

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