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Using 40 Gig ports on a 8770 and am not getting flow control to work on edge ports

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TitleUsing 40 Gig ports on a 8770 and am not getting flow control to work on edge ports
As a Spine switch the 8770 is likely to be used both for ISL port distribution to all Leaf nodes but also for edge ports that are often connected to upstream routers, firewalls, and other shared data center modules such as IP storage clouds. More often we are seeing the use of 40G circuits being used as both ISL's and edge ports.

In the topology below the 8770 Spine switches are using 40G circuits as both ISL's to the Leaf 6740 switches and 40G circuits in Port-Channels to the IP storage switches as shown on the right side of the topology below:

Software Release: N/A
Fixed in Version: N/A
As shown in the NOS Release Notes from 5.0.1 forward, 40G ports on the VDX8770 blades do not honor 802.3x pause frames. This is to enable pause functionality. It is recommended to configure breakout mode, which will result into 4x10G interfaces that would support the pause functionality. Further more the 8770 blades with 40G interfaces do not honor PFC as shown in the scenario above.
Use Breakout ports to connect four 10Gig circuits to the same interface utilizing breakout SFP's. Breaking the circuits down into 10G interfaces will allow the 8770 Spine switch to properly adhere to the 802.3 pause frames as well as PFC pause frames required to signal end to end flow control.
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