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To flow or not to flow?

NetApp’s newest storage operating system, clustered Data ONTAP (cDOT), leverages a backend of Cisco Nexus switches for it’s cluster interconnect network.

When configuring the switch/cluster ports for use with cDOT, the best practice is to turn flow control off as per TR-4182. In fact, that happens to be the recommendation for normal data ports as well. Why is that? Before we get into that, let’s cover the basics…

What is flow control?

Flow control is a mechanism used to help manage the rate of data transfer between two devices. This is done to help prevent a source evice from overwhelming a destination device by sending more packets than the destination can handle. These scenarios can occur if a source device is faster than the destination device (CPU, RAM, NIC, etc). This can also happen if the source is intentionally trying to flood the destination via a malicious Denial of Service (DoS) attack.

Flow control can be enacted for send or receive packets, or both. It can be hardware or software based. It can occur at multiple layers of the OSI model

For a real world analogy to flow control, think of how dams work. A dam will be installed to control the flow of water on a river, usually to create lakes or reservoirs. Dams can be used to adjust the water flow to prevent flooding, depending on rainfall. Network flow control does pretty much the same thing – it prevents data floods. Read More »

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Customer Insight: Automotive Dealership Group saves $100,000 annually with Cisco Unified Data Center Solutions

Are you in the market for a new car in this year? Automotive retailers compete for your business in one of the most competitive industries, so reducing infrastructure and operating costs is key to selling you a car at the price you want.

Hendrick Automotive Group is the second largest privately held automotive retailer in the US, with 7,000 employees and 80 dealerships. Watch the 3:39 minute video for more information on how Hendrick is running every mission critical application on UCS, saving more than $100,000 annually, and helping the IT department become a profit center while offering superior service to both their employees and customers.

You can read the entire story here, Hendrick Automotive Group

A Better Data Center with Cisco UCS

What’s been your experience with consolidation and virtualization in your data center?  Are planning to use UCS in your data center? Join the conversation.

>> Interested in reading UCS customer success stories in your region?  Read more at Data Center Case Studies

>> Yes, Cisco UCS servers are really that good, Read Bill Shield’s blog

>> To find out more about Cisco Unified Data Center solutions,

go to: www.cisco.com/go/dc and Cisco Unified Computing Systems at www.cisco.com/go/ucs.

 

 

 

 

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