The value of Connectors in the workplace

In Malcolm Gladwell’s book The Tipping Point [affiliate link] the author identifies key roles that individuals play in spreading knowledge and ideas. Gladwell outlines two key roles, the maven and the connector. The maven is a person who accumulates subject matter expertise and is willing to distribute that knowledge on request. Think of a maven […]

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John Harrington

John is an experienced data center engineer with a background in mobile telecoms. He works as a network test engineer for a large cloud service provider, and is gradually accepting that he's a nerd. He blogs about network technology and careers at theNetworkSherpa.com. You can reach him on twitter at: @networksherpa

The post The value of Connectors in the workplace appeared first on Packet Pushers Podcast and was written by John Harrington.

Ageism and your career in I.T.

I recently decided to commit to my current company.  I don’t mean work harder or focus more, though that’s implicit.  I mean to consider being a “lifer.”  For an independent personality like myself that’s a pretty tall leap.  One of the reasons I got my CCIE was to avoid ever being the guy sweating when […]

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Keith Tokash

Keith Tokash

Keith Tokash, CCIE (R&S) #21236, began his career in 1999, and has spent the last decade running around large content and small ISP networks. He spends his spare time with his newborn son, on the mat at the local Jiu-Jitsu gym, and trying to keep his fat yap shut.

The post Ageism and your career in I.T. appeared first on Packet Pushers Podcast and was written by Keith Tokash.

Software Defined Data Centres and the blending of cultures

As some of you may know, I have spent a fair amount of my time in the last few years designing and improving multi-tennant hosting environments. Each revision attempts to learn from the mistakes of the previous iterations, as well as bundle in new features and “advancements” from each of the different vendors in the stack.

New offerings on the storage fronts, developments in the server space in the form of the boom of virtualisation, and the simple existence of the network amongst the fact that none of these technologies changed the existing/fundamental laws of networking.

Software-Defined Networking has sprung up as a way of providing both advancements in our current architectures and providing agility in changes needed in the future, but what is truly needed is a true abstraction of the entire data centre model that encompassed all of compute, storage, security and networking. The ability to define all of the requirements of your existing data centre and have them deployed and rolled out across which ever stack you are using (Private / Public / Hybrid / Tomorrows Favourite buzz.), in a consistent and definable manner.

Merging the requirements of each of the existing silos and describing Continue reading

AdaptingIT: Why I Started a Podcast Featuring Women in Tech

As a systems admin a few years back I decided that I needed to figure out a way to understand networking.  I could do basic things, but how do you figure out what you don’t know?  That’s when I started listening to podcasts.  The first podcast I came across was Packet Pushers and I haven’t […]

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Lauren Malhoit

Lauren Malhoit

The post AdaptingIT: Why I Started a Podcast Featuring Women in Tech appeared first on Packet Pushers Podcast and was written by Lauren Malhoit.

When it’s OK to say “No”

A lot of us struggle in our careers when it comes to accepting or declining work, whether it be voluntary or voluntoldary. Especially the individuals in our field that strive to succeed. We see it as another opportunity to stand up to the plate and knock one out of the park. The problem, however, is that […]

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Edward Henry

Edward Henry is currently employed with a regional optical network concentrating on Research and Education within the communities of Connecticut. Along with his day job, Edward is an avid techy and has been working toward advancing his career with all things nerdy. Also follow Ed on Twitter : @NetworkN3rd and at his personal blog : https://networkn3rd.wordpress.com

The post When it’s OK to say “No” appeared first on Packet Pushers Podcast and was written by Edward Henry.

Cisco UCS vNIC Switchport Mode

I wrote an article a while back regarding VLAN configuration when running vSphere ESXi on top of Cisco UCS. A comment pointed out that all vNICs are automatically configured as trunks. I had not heard of this before, so I got into the CLI to take a look. Here’s a VLAN configuration screen in the UCSM GUI for a sample vNIC: Check out the running configuration for this vNIC on the underlying NX-OS CLI.

Cisco UCS vNIC Switchport Mode

I wrote an article a while back regarding VLAN configuration when running vSphere ESXi on top of Cisco UCS. A comment pointed out that all vNICs are automatically configured as trunks. I had not heard of this before, so I got into the CLI to take a look. Here’s a VLAN configuration screen in the UCSM GUI for a sample vNIC: Check out the running configuration for this vNIC on the underlying NX-OS CLI.

Network Toolkit

My case full of network doodads always generates lots of questions when people see it for the first time. I don't carry dedicated iPhone chargers anymore, but Apple cube chargers forgotten behind hotel nightstands is where this started.

With this kit it is immediately apparent when something is missing, so things tend to not get left behind.

The limited space has driven me to find the best and most compact solutions to all of my problems. I'm really pleased with everything that's in here. I'm also aware that it's super nerdy.


The case itself is a Duluu Essential case for iPad. It's a nice semi-rigid clamshell type case. I've made two modifications:

  1. Removed the padded "page" between the two halves. This thing was intended to keep the stuff in the pockets on the left from scratching the iPad on the right. It also served as an iPad stand.
  2. I removed the original zipper pulls, replaced them with a repair part because the square corners of the original pulls tended to cause problems.
On the right side of the case I've installed a bit of floor padding foam (this kind of thing, but mine came from Harbor Freight Tools), Continue reading

Applications…Meet Your Network

If you’ve been following Embrane over the past several months, you know we’ve been focusing almost exclusively on differentiating our business in the SDN space by promoting the fact that we have been the only company securing and announcing a steady stream of paying, in-production customers.  As a result, we’ve been placing less emphasis on touting the advancements we’ve made on the technology side. However, since it’s our technology leadership that’s attracting our rapidly growing customer base, it’s time to show off our technology chops too. This week our SDN leadership becomes even more evident with the introduction of our new application-centric networking solutions.

(Okay, it’s not exclusively a technology announcement since we announced another new customer, Ryan Labs Asset Management. More on them in a bit.)

While most vendors started their SDN movement from the bottom up, looking at ways to add agility at the connectivity layer (a.k.a. Layer 2), Embrane continues to take a top-down approach to the network. We focus on the network services that support, enhance and secure the ever-growing number of business applications in an enterprise data center. After all, applications drive enterprises business. The newest release of the Embrane heleos Continue reading

IPv6 RA Router Advertisement and all the flags inside

How does the internet work - We know what is networking

I can say at the beginning that more and more fellows is visiting this blog. Finally networking knowledge project did succeed to get some fans from out there so I felt the need to thank you all for visiting this place. As you can see here from the blog post list I didn’t follow this movement myself these […]

IPv6 RA Router Advertisement and all the flags inside

Cisco onePK Screencast

As a follow-on to my previous article on onePK – Cisco onePK: Now I Get It – I recorded a screencast in which I talk about what a onePK-enabled network is capable of. I also demonstrate two applications which make use of onePK to gather telemetry from the network and also program the network.

  • MTU Checker – Verifies that when the MTU of an interface is changed on the CLI, that the adjoining interface MTU matches
  • Routing For Dollars – Programs the forwarding table of the routers in the network based on the cost – in terms of dollars – of the various links in the network

Please leave a comment below with any questions or feedback.

Copyright Joel Knight. All Rights Reserved.
www.packetmischief.ca

Junos and BGP FlowSpec

Introduction Recently I carried out tests in labs to evaluate the FlowSpec implementation on MX960 router with TRIO MPC cards. I used a 12.3 Junos release. Those tests have covered: - IPv4 blackholing traffic feature - IPv4 rate-limiting traffic feature...

Junos and BGP FlowSpec

Introduction Recently I carried out tests in labs to evaluate the FlowSpec implementation on MX960 router with TRIO MPC cards. I used a 12.3 Junos release. Those tests have covered: - IPv4 blackholing traffic feature - IPv4 rate-limiting traffic feature...

Show 154 – A Bit of Swamp Ass to Lift Your Day – CLUS 2013 Community Show

In this community show recorded at Cisco Live US 2013 in Orlando, Cooper Lees, Lauren Mahoit and Colin McNamara join Packet Pushers hosts Greg Ferro and Ethan Banks in a happy chat about the coming world of networking automation. We discuss the following high-level topics. Automation, orchestration and devops in the network is becoming an ever-bigger deal. We apply this in a Cisco […]

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Ethan Banks

Co-host at Packet Pushers

Ethan Banks, CCIE #20655, has been managing networks for higher ed, government, financials and high tech since 1995. Ethan co-hosts the Packet Pushers Podcast, which has seen over 3M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks
TwitterGoogle+LinkedIn

The post Show 154 – A Bit of Swamp Ass to Lift Your Day – CLUS 2013 Community Show appeared first on Packet Pushers Podcast and was written by Ethan Banks.

Cisco onePK Screencast

As a follow-on to my previous article on onePK — Cisco onePK: Now I Get It — I recorded a screencast in which I talk about what a onePK-enabled network is capable of. I also demonstrate two applications which make use of onePK to gather telemetry from the network and also program the network. MTU Checker - Verifies that when the MTU of an interface is changed on the CLI, that the adjoining interface MTU matches Routing For Dollars - Programs the forwarding table of the routers in the network based on the cost — in terms of dollars — of the various links in the network Please leave a comment below with any questions or feedback.

PQ Show 29 – How To Prepare for the CCDE

At Cisco Live US 2013 in Orlando, Packet Pushers co-host Ethan Banks was joined by CCDE program manager Elaine Lopes, CiscoPress author Russ White who was closely involved with the CCDE program creation, quad-CCIE & CCDE Scott Morris, and CCIE & CCDE Jeremy Filliben who instructs a CCDE bootcamp. We discuss (what else) how to […]

Author information

Ethan Banks

Co-host at Packet Pushers

Ethan Banks, CCIE #20655, has been managing networks for higher ed, government, financials and high tech since 1995. Ethan co-hosts the Packet Pushers Podcast, which has seen over 3M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks
TwitterGoogle+LinkedIn

The post PQ Show 29 – How To Prepare for the CCDE appeared first on Packet Pushers Podcast and was written by Ethan Banks.

Quality of Service (QoS) Congestion Management Notes

Of all the tools within the QoS toolset, congestion management tools, also known as queuing tools, provide the biggest impact on application service levels.  Whenever packets enter a device faster than can exit it, congestion exists and this is where queuing tools come into play.  Queuing tools are only engaged when congestion exists, otherwise packets are sent as soon as they arrive.  When congestion does exist, packets must be buffered, or queued, to mitigate dropping.

Packet markings, or lack thereof, affect queuing policies, so queuing policies are complementary and have a dependence on classification and marking policies.

Scheduling vs. Queuing

These two terms are often incorrectly used interchangeably – they are two different things.  Scheduling determines how a frame or packet exits a device. Whenever packets enter a device faster than they can exit it, as is the case with speed mismatches (ex. Gigabit Ethernet traffic heading to a WAN interface), congestion can occur.  Devices have buffers that allow the temporary storing and subsequent scheduling of these backed-up packets, and this process is called queuing.

Inbound traffic > Queuing (During congestion) > Scheduling > Outbound traffic

Quality of Service (QoS) Classification and Marking Notes

The first part of building a QoS policy is to identify the traffic that you need to treat preferentially (give better priority), or differentially.  This is accomplished via classification and marking.

  • Classification – sorts packets into different traffic types that policies can then be applied to.
  • Marking (or re-marking) – establishes a trust boundary on which scheduling tools later utilize.  The edge of the network where markings are either accepted or rejected is known as the trust-boundary.
  • Classifier tools – Inspect one or more fields in a packet to identify the type of traffic that is being carried. After being identified, it is passed to the appropriate mechanism to handle that type of traffic class.
  • Marking tools – actually write a field within the packet (or frame, cell, label) to preserve the classification decision.  By marking traffic at a trust boundary, subsequent nodes do not have to perform the same in-depth analysis to determine how to treat the packet.

Classification Tools

These tools can examine a number of criteria within layers 1, 2, 3, 4, and 7.

  • L1 – Physical interface, subinterface, PVC, port
  • L2 – MAC, 802.1Q/p CoS, VLAN, MPLS EXP, ATM Cell Continue reading

Checksum Verification

Occasionally I have to install software that is no longer available for download via the official channels. This is due to us having pretty strict standards on which IOS versions are stable and suitable for use via a bug scrub process that Cisco are party to.

I could speak to our Cisco SE and ask for the image to be provided, but it’s simpler and quicker to find a similar piece of kit on the network and FTP/SCP the image across.

I did this today, and then realised that I couldn’t rely on CCO to give me the MD5 sum for the image. A quick google tells me that I can perform a checksum on the switch using this command:

verify /md5 <file-location>:<file-name>

Location choices are:

bs: File to be verified
cns: File to be verified
flash: File to be verified
ftp: File to be verified
http: File to be verified
https: File to be verified
null: File to be verified
nvram: File to be verified
rcp: File to be verified
scp: File to be verified
system: File to be verified
tar: File to be verified
tftp: File to be verified
tmpsys: File to be verified
xmodem: File to be Continue reading

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