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Summary: Use Rate-Limiting to Alleviate Link Saturation

Here’s the scenario: you have a remote branch office in Miami that has been running smoothly for months. Today you are getting complaints from the site that relate to phone calls dropping, email and network connectivity being intermittent. Management is pushing your team to get it fixed.

You start by looking closely at the WAN circuit going into the site. You use a program that Cisco introduced called NetFlow. By using this program you are able to determine that the WAN link is being saturated by a particular server to server file transfer. You need a quick fix to this issue. You could go with QoS but that could take some time and input from the site to gather statistics on the critical traffic. Instead you decide to utilize Rate-Limiting on the WAN interface.

Tags: #CiscoChampion, #CiscoEnterprise, #NetworkEngineer

Read the full article here.

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#CiscoChampion Radio S2|Ep 5. VersaStack

CiscoChampion2015200PX#CiscoChampion Radio is a podcast series by Cisco Champions as technologists. Today we’ll be talking with Cisco Technical Marketing Engineers Jeffrey Fultz and Shiva Shastri about Cisco VersaStack. Our Cisco Champion guest host is Enda Cahill.

Listen to the Podcast.

Learn about the Cisco Champions Program HERE.
See a list of all #CiscoChampion Radio podcasts HERE.

Cisco SMEs
Jeffrey Fultz, Cisco Technical Marketing Engineer
Shiva Shastri, Cisco Technical Marketing Engineer

Cisco Champion Guest Hosts
Enda Cahill, @Saineolai, Technical Director

Highlights
What is VersaStack?
VersaStack and UCS Director
What makes the VersaStack different?
Why the name VersaStack?
VersaStack and storage Read More »

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Cisco UCS Mini – a deep dive

In September 2014, Cisco launched the UCS Mini for what they dubbed “Edge-Scale Computing”. The UCS Mini offering is a stripped down version of the classic UCS system with Fabric Interconnects. To learn about classic UCS, click here.

In this post I will go into some details about the UCS Mini that I’ve learned over the past few months. The information here will assume you have the basic knowledge about what the UCS Mini is and what components are involved. If you need a refresher, I’ve written up a small introduction here.

Let’s dive in.

Fabric Interconnect

The UCS FI 6324 is the same size as the UCS I/O Modules (IOM 2208XP, 2204XP, etc) and fits in the back IOM slot of the UCS Chassis 5108 (version 2).

ucs-fi-6324-breakdown Read More »

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#CiscoChampion Radio S2|Ep 4. VIRL

CiscoChampion2015200PX#CiscoChampion Radio is a podcast series by Cisco Champions as technologists. Today we’ll be talking with Cisco Distinguished Engineer Joel Obstfeld about VIRL. Our Cisco Champion guest hosts are Brad Haynes and Scott Morris.

Listen to the Podcast.

Learn about the Cisco Champions Program HERE.
See a list of all #CiscoChampion Radio podcasts HERE.

Cisco SMEs
Joel Obstfeld, Cisco Distinguished Engineer

Cisco Champion Guest Hosts
Brad Haynes, @GK_bradhaynes, Client Solutions Specialist
Scott Morris, @ScottMorrisCCIE, Senior Instructor

Highlights
What is VIRL
VIRL Wow features
VIRL and CML
Who will benefit from VIRL
Deployment scenarios

Resources
http://virl.cisco.com/

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Defending Your Console

A new problem has arisen in CCNA class: We have a lab that asks the students to enable a debug command; the debug overruns the console buffer to the extent that commands cannot be entered, and this goes on for more than an hour!

In my 15 years of teaching CCNA classes, we have always taught the dangers of using debug commands on production equipment. To demonstrate this, we would have the students run the debug ip packet command, let it run for 30 seconds, and then turn it off. Of course, turning off the debug is challenging, so we would teach the trick of turning the debug off before we would turn it on: adding the undebug all command to our command history buffer.

Running this test on the 2500 series and 2600 series routers would usually cause a crash and a forced reboot. After we changed the lab equipment to the newer ISR 2800 series, the same demonstration no longer resulted in a router crash; however, it introduced a new problem: loss of control of the command line.

The sheer amount of debug messages would cause the command line to be unusable. The debug messages continued to overrun the console buffer for over an hour before we would finally run out of patience and power cycle the router. In a lab scenario, this causes the students to take an excessive amount of time to finish their lab, and for people studying for certifications, it wastes precious study time. A better way to manage debugs is needed. We would like to see the debug messages (they can be very helpful in both troubleshooting and understanding how protocols function), but we would also like to retain control of the command line. Read More »

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