Troubleshooting Cisco Network Elements with the USE Method

I want to draw some attention to a new document I’ve written titled “Troubleshooting Cisco Network Elements with the USE Method“. In it, I explain how I’ve taken a model for troubleshooting a complex system–the USE Method, by Brendan Gregg–and applied it to Cisco network devices. By applying the USE Method, a network engineer can perform methodical troubleshooting of a network element in order to determine why the NE is not performing/acting/functioning as it should.

I ask that if you’re familiar with a given Cisco network platform (or platforms), that you please contribute commands that would also fit into the USE Method! My list is just a start and I welcome contributions from others in order to make it a stronger, more valuable reference.

Please check out the guide: Troubleshooting Cisco Network Elements with the USE Method

Original article: Troubleshooting Cisco Network Elements with the USE Method

Copyright © 2017 Joel Knight . All Rights Reserved.

SDxCentral’s Top 10 Articles — July 2017

Juniper gets a new CTO from Google; Find out how Cisco's intent-based networking works.

What is IPv6 Dual stack? What does IPv6 dual stack exactly mean?

What is IPv6 dual stack ?  From some questions and comments on the website, I understand that there is a confusion about it. So, what does exactly dual stack IPv6 mean ?   IPv6 is not a luxury anymore. It is not avoidable for the Service Providers especially.   The biggest problem for the Service Providers […]

The post What is IPv6 Dual stack? What does IPv6 dual stack exactly mean? appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.

14 Storage Startups Breaking New Ground

Why ALL African Internet and Data operators should be attending AfPIF-2017

Configuring Voice VLANs

Today I am going to talk about the Voice VLAN. The Voice VLAN feature enables the VLAN to carry the voice traffic. So you have a switch with is connected to the IP Phones, it can be of Cisco Avaya or any other and is connected to the specified VLANs or you can name them Voice VLANs in your network. So when switch is connected to the IP phones, the connected switch sends the voice traffic with layer 3 IP precedence and Layer 2 class of service in short name as COS values which are set as default of value 5. That is the reason because the sound quality of an IP phone call can deteriorate if the data is unevenly sent, the switch supports quality of service (QoS) based on IEEE 802.1p CoS. 

Fig 1.1- Sample Topology- Switch and IP Phone

We can configure an access port with an attached Cisco IP Phone to use one VLAN for voice traffic and another VLAN for data traffic from a device attached to the phone. We can configure access ports on the switch to send Cisco Discovery Protocol (CDP) packets that instruct an attached phone to Continue reading

The Languages Which Almost Became CSS

This was adapted from a post which originally appeared on the Eager blog. Eager has now become the new Cloudflare Apps.

In fact, it has been a constant source of delight for me over the past year to get to continually tell hordes (literally) of people who want to – strap yourselves in, here it comes – control what their documents look like in ways that would be trivial in TeX, Microsoft Word, and every other common text processing environment: “Sorry, you’re screwed.”

— Marc Andreessen 1994

When Tim Berners-Lee announced HTML in 1991 there was no method of styling pages. How a given HTML tag was rendered was determined by the browser, often with significant input from the user’s preferences. To Continue reading

Troubleshooting Cisco Network Elements with the USE Method

Troubleshooting Cisco Network Elements with the USE Method

Getting Started: Writing Your First Playbook

Welcome to another post in our Getting Started series. Keep reading to learn how to draft a Playbook that can be run in Ansible or Ansible Tower. You can also use it along with the Module Index and the other docs to build your own Playbooks later.

What is a Playbook?

Playbooks are esentially sets of instructions (plays) that you send to run on a single target or groups of targets (hosts). Think about the instructions you get for assembling an appliance or furniture. The manufacturer includes instructions so you can put the parts together in the correct order. When followed in order, the furniture looks like what was purchased.

That's basically how a Playbook works.

The Playbook we're building will install a web server on a target RHEL/CentOS 7 host, then write an index.html file based on a template file that will reside with the final Playbook. You'll be able to take the example Playbook and additional files from this blog and test it out for yourself. While going over the example Playbook, we'll explain the modules that are used.

The author adds instructions for the modules to run, often with additional values (arguments, locations, etc. Continue reading

EVPN-VXLAN lab – basic L2 switching

My EVPN-VXLAN lab topology:

There is IP Fabric in DC1 (2 vMX and 2 vQFX), and 2 vMX_v14 to emulate CE devices. Each CE device connected to EVPN via LACP LAG ae0 (EVPN Active-Active ethernet segment on service side). vMX_old-1 also has sigle-homed interface ge-0/0/4 (just to show you the difference).
Each CE device split into two logical systems for more convenient testing of routing functionality (global device context for Vlan100 and logical-system second for Vlan200). You could also use virtual-router routing instances for that, if you prefer this way. The rest of CE config is pretty self-explanatory:

IDC: SD-WAN growth is exploding for at least the next 5 years

As network pros rely more and more on SD-WAN to streamline connections among enterprise sites, the market for this technology will balloon from $225 million in 2015 to $1.19 billion by the end of this year, according to IDC.Over the next five years, SD-WAN sales will grow at a 69% compound annual growth rate, hitting $8.05 billion in 2021, according to IDC’s Worldwide SD-WAN Forecast, 2017–2021.As businesses adopt what IDC calls “third-platform” technologies such as cloud, mobile, big data and analytics, they put increased strain on the network. As organizations look to better connect their remote and branch office employees and provide them better quality network services, SD-WAN will continue to grow.To read this article in full or to leave a comment, please click here

IDC: SD-WAN growth is exploding for at least the next 5 years

As network pros rely more and more on SD-WAN to streamline connections among enterprise sites, the market for this technology will balloon from $225 million in 2015 to $1.19 billion by the end of this year, according to IDC.Over the next five years, SD-WAN sales will grow at a 69% compound annual growth rate, hitting $8.05 billion in 2021, according to IDC’s Worldwide SD-WAN Forecast, 2017–2021.As businesses adopt what IDC calls “third-platform” technologies such as cloud, mobile, big data and analytics, they put increased strain on the network. As organizations look to better connect their remote and branch office employees and provide them better quality network services, SD-WAN will continue to grow.To read this article in full or to leave a comment, please click here

Worth Reading: LinkedIn passes an IPv6 milestone

Since we enabled IPv6 on our mail servers in 2013 and then on our web site in 2014, we have seen increased growth of our external IPv6 traffic. We are currently working on enabling IPv6 on our all of our internal networks and applications in order to begin removing IPv4 internally, beginning in 2018. The external network and public services will still support IPv4 (for compatibility with legacy clients) for years to come, but we anticipate the proportion of our external traffic served over IPv6 to only increase. The community has seen tangible benefits from serving content over IPv6 compared to IPv4. We, too, see some performance improvements on IPv6. —LinkedIn Engineering Blog

The post Worth Reading: LinkedIn passes an IPv6 milestone appeared first on rule 11 reader.

Data Center Physical Realities in a Software-Defined World

Cisco’s Nexus 9516 review: About line rate

Much ink has been spilled on the topic of what constitutes true “line rate,” and in the past we’ve advocated offering traffic at, and only at, 100.00 percent of theoretical line rate to determine if frame loss exists. However, the distinction between 99.99 percent (which we used in these tests) and 100.00 percent load is not all that meaningful, especially at higher Ethernet speeds, for a couple of reasons. First, Ethernet is inherently an asynchronous technology, meaning each device (in this case, the device under test and the test instrument) uses one or more of its own free-running clocks, without synchronization. Thus, throughput measurements may just be artifacts of minor differences in the speeds of clock chips, not descriptions of a system’s fabric capacity.To read this article in full or to leave a comment, please click here

Cisco’s Nexus 9516 review: About line rate

Much ink has been spilled on the topic of what constitutes true “line rate,” and in the past we’ve advocated offering traffic at, and only at, 100.00 percent of theoretical line rate to determine if frame loss exists. However, the distinction between 99.99 percent (which we used in these tests) and 100.00 percent load is not all that meaningful, especially at higher Ethernet speeds, for a couple of reasons. First, Ethernet is inherently an asynchronous technology, meaning each device (in this case, the device under test and the test instrument) uses one or more of its own free-running clocks, without synchronization. Thus, throughput measurements may just be artifacts of minor differences in the speeds of clock chips, not descriptions of a system’s fabric capacity.To read this article in full or to leave a comment, please click here

Managing Deep Learning Development Complexity

For developers, deep learning systems are becoming more interactive and complex. From the building of more malleable datasets that can be iteratively augmented, to more dynamic models, to more continuous learning being built into neural networks, there is a greater need to manage the process from start to finish with lightweight tools.

“New training samples, human insights, and operation experiences can consistently emerge even after deployment. The ability of updating a model and tracking its changes thus becomes necessary,” says a team from Imperial College London that has developed a library to manage the iterations deep learning developers make across …

Managing Deep Learning Development Complexity was written by Nicole Hemsoth at The Next Platform.

Cisco’s Nexus 9516 review: About line rate

Much ink has been spilled on the topic of what constitutes true “line rate,” and in the past we’ve advocated offering traffic at, and only at, 100.00 percent of theoretical line rate to determine if frame loss exists. However, the distinction between 99.99 percent (which we used in these tests) and 100.00 percent load is not all that meaningful, especially at higher Ethernet speeds, for a couple of reasons. First, Ethernet is inherently an asynchronous technology, meaning each device (in this case, the device under test and the test instrument) uses one or more of its own free-running clocks, without synchronization. Thus, throughput measurements may just be artifacts of minor differences in the speeds of clock chips, not descriptions of a system’s fabric capacity.To read this article in full or to leave a comment, please click here

Cisco Nexus 9516 review: How we did it

The device under test for this project was the Cisco Nexus 9516 data center core switch/router, a 16-slot chassis equipped with 1,024 50-gigabit Ethernet interfaces and two supervisor modules. Cisco equipped the switch with its N9K-X9732C-EX line cards, each of which offers 32, 64, or 128 ports of 100-, 50-, and 25-gigabit Ethernet capacity.The traffic generator/analyzer was Spirent TestCenter equipped with its 10/25/40/50/100G MX3 modules. The Spirent instrument has a measurement precision of +/- 2.5 nanoseconds.To read this article in full or to leave a comment, please click here