I am trying to understand the best practice for flowcontrol in a NetApp environment. I have a NetApp filer connected to a Catalyst 6509 (WS-X6716-10GE).
NetApp provides the following direction for flowcontrol:
"For modern network equipment, especially 10GbE equipment, NetApp recommends turning off flow control and allowing congestion management to be performed higher in the network stack." (http://www.netapp.com/us/media/tr-3749.pdf page 25)
However the Catalyst 6500 best practice guide is less clear
(http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/best/practices/recommendations.html#wp1039880 section 1.10) which states:
1.10.5.2 Recommended General Port Configuration
If you have decided to drop frames at the Catalyst 6500 switch port instead of on the far-end device, configure the port to respond to pause frames:
•
If you know that the device is capable of negotiating flow control, enter this command:
Router(config-if)# flowcontrol receive •
Router(config-if)# flowcontrol receive desired
Is there any Cisco recommended configuration in these 10G environments?
One additional question, the NetApp appliance is connected to one switch, the clients are connected to a different switch. Can you tell me how PAUSE frames work in that environment? I've read the following:
PAUSE frame are sent to the globally assigned multicast address 01-80-C2-00-00-01 (hex). This multicast address has been reserved by the IEEE 802.3 standard for use in MAC Control PAUSE frames. It is also reserved in the IEEE 802.1D bridging standard as an address that will not be forward by bridges. This ensures the frame will not propagate beyond the local link segment.
Does this mean that PAUSE frames sent by the client will not be received by the NetApp appliance (assuming both switches are set to send & receive these frames)?
Thank you for the assistance.
