Checking Faulty Cables

I recently had to work with a 3rd part to diagnose a link between our devices and came across this handy command. The link in question was a pretty hefty (75m-ish) UTP cable run between a Cisco and HP switch. I have visibility of the Cisco switch, into the structured cabling into the patch panel, and the 3rd parties cable. Unfortunately I didn’t have a DC Operations tech with access to a Fluke, or the ability to interpret the output of a Fluke, but they did have a laptop with a 100Mbps NIC (this becomes important later on).

So I started by running the diagnostic on the production connection. It’s not working, so I don’t have to worry about taking stuff down. This gives me the following:

test cable-diagnostics tdr interface gi7/21
TDR test started on interface Gi7/21
A TDR test can take a few seconds to run on an interface
Use 'show cable-diagnostics tdr' to read the TDR results.

switchA#show cable-diagnostics tdr interface gi7/21

TDR test last run on: July 09 10:30:20
Interface Speed Pair Cable length Distance to fault Channel Pair status
——— —– —- ——————- ——————- ——- ————
Gi7/21 auto 1-2 77 +/- 6 m N/A Invalid Continue reading

The Upload: Your tech news briefing for Tuesday, July 14

As partner conference kicks off, Microsoft details Win10 launch plans and moreWith Windows 10 set to roll out in just two weeks, Microsoft on Monday shed some light on the marketing support it will put behind the launch: a worldwide, year-long “upgrade your world” ad campaign. And at its annual Worldwide Partner Conference that started in Orlando, Microsoft rolled out a new analytics tool that aims to democratize access to big data using the Cortana voice interface, as well as Project Gigjam, which can pull data from multiple applications into a shared workspace.To read this article in full or to leave a comment, please click here

The Upload: Your tech news briefing for Tuesday, July 14

As partner conference kicks off, Microsoft details Win10 launch plans and moreWith Windows 10 set to roll out in just two weeks, Microsoft on Monday shed some light on the marketing support it will put behind the launch: a worldwide, year-long “upgrade your world” ad campaign. And at its annual Worldwide Partner Conference that started in Orlando, Microsoft rolled out a new analytics tool that aims to democratize access to big data using the Cortana voice interface, as well as Project Gigjam, which can pull data from multiple applications into a shared workspace.To read this article in full or to leave a comment, please click here

IPv6 Multicast

These are my notes for IPv6 multicast for the CCDE exam. Overview

  • Prefix FF::/8 reserved for multicast
  • Multicast Listener Discovery (MLD) replaces IGMP
    • MLD is part of ICMPv6
    • MLDv1 equivalent to IGMPv2
    • MLDv2 equivalent to IGMPv3
  • ASM, SSM and Bidir supported
  • PIM identified by IPv6 next header 103
  • BSR and static RP supported
  • No support for MSDP
    • Anycast supported through PIM, defined in RFC4610
  • Any Source Multicast (ASM)
    • PIM-SM, PIM-BiDir
    • Default for generic multicast and unicast prefix-based multicast
    • Starts with FF3x::/12
  • Source Specific Multicast (SSM)
    • PIM-SSM
    • FF3X::/32 is allocated for SSM by IANA
    • Currently prefix and plen is zero so FF3X::/96 is useable for SSM
  • Embedded RP groups
    • PIM-SM, PIM-BIDir
    • Starts with FF70::/12

IPv6 Multicast Addressing

IPv6 multicast address format includes variable bits to define what type of address it is and what the scope is of the multicast group. The scope can be:

1 – Node

2 – Link

3 – Subnet

4 – Admin

5 – Site

8 – Organization

E – Global

The flags define if embedded RP is used, if the address is based on unicast and if the address is IANA assigned or not (temporary). The unicast based IPv6 multicast address allows an organization to Continue reading

9 things you didn’t know about Google’s undersea cable

Undersea cables carry virtually all transoceanic Internet data these days, replacing satellites as the preferred medium. Google and some telecom companies invested in one of them, called FASTER, that will stretch 9,000 kilometers between the U.S. and Japan and is due to go into operation next year.With six fiber-pairs in the cable, each carrying 100 wavelengths at 100 gigabits per second, it will have a peak capacity of 60 terabits per second (Tbps). That’s about 10 million times faster than a standard cable modem.Here are some facts about undersea cables and about the FASTER system in particular.To read this article in full or to leave a comment, please click here

Dual Stack Routed Access Layer With OSPF Design Guide

This is a design guide for an enterprise deployment of a dual stack, routed access layer using OSPF as the routing protocol, with a fully routed ECMP core.

Author information

Matt Love

Matt Love

Matt is a network engineer in Greenville, SC, USA. He enjoys solving complex routing, data center, and security (ish) problems, and writes about those when he can. When not at work, Matt can be found traipsing around Greenville on a road bike, or at home with his wife and two study-preventing kids.
TwitterLinkedIn

The post Dual Stack Routed Access Layer With OSPF Design Guide appeared first on Packet Pushers Podcast and was written by Matt Love.

Book review: The Book of GNS3

GNS3coverNo Starch Press recently offered me a preview copy of a new book about the GNS3 network simulator, titled The Book of GNS3 written by Jason Neumann. This book covers the new version of GNS3, GNS3 1.x. Here is my review of The Book of GNS3.

The Book of GNS3 effectively serves as a user manual for GNS3. It offers detailed installation and configuration information for GNS3 1.x in one easy-to-access volume. Experienced users will find some new information in this book, especially about the new features available in GNS3 1.x. However, I think the main beneficiaries will be new or inexperienced users of GNS3.

GNS3 is usually used by people who wish to emulate networks of commercial routers from vendors such as Cisco and Juniper. Understandably, Mr. Neumann spends most of the book discussing how to set up GNS3 to run commercial routers and, as much as is possible, switches.

How does this book help those who want to use open-source routers in GNS3? Read the rest of my review to find out.

Coverage of Open-Source Routing topics

While I read through this book, I looked for the parts that are relevant to my interests in Continue reading

ProxyHam conspiracy is nonsense

This DEF CON conspiracy theory is about a canceled talk about "ProxyHam", which has been canceled under mysterious circumstances. It's nonsense.

The talk was hype to begin with. You can buy a 900 MHz bridge from Ubquiti for $125 (or MicroTik device for $129) and attach it to a Raspberry Pi. How you'd do this is obvious. It's a good DEF CON talk, because it's the application that important, but the technical principles here are extremely basic.

If you look careful at the pic in the Wired story on ProxyHam, it appears they are indeed just using the Ubuiti device. Here is the pic from Wired:


And here is the pic from Ubquiti's website:


I don't know why the talk was canceled. One likely reason is that the stories (such as the one on Wired) sensationalized the thing, so maybe their employer got cold feet. Or maybe the FBI got scared and really did give them an NSL, though that's incredibly implausible.

Anyway, if DEF CON wants a talk on how to hook up a Raspberry Pi to a UbiQuiTi NanoStation LOCOM9 in order bridge WiFi, I'll happily give that talk. It's just basic TCP/IP configuration, and if you Continue reading

CIA: Julia Child and the shark repellant recipe

CIA Sometimes some of the coolest stories get lost in history. The CIA recently noted one of them – famous French food chef and author Julia Child’s critical involvement in developing a shark repellent recipe for military personnel and explosives during WWII.+More on Network World: The hot art in the CIA’s cool art collection+To read this article in full or to leave a comment, please click here

IBM, Nvidia rev HPC engines in next-gen supercomputer push

Hard on the heels of the publication of the latest Top 500 ranking of the world’s fastest supercomputers, IBM and Nvidia on Monday announced they have teamed up to launch two new supercomputer centers of excellence to develop the next generation of contenders.Created as part of IBM’s supercomputing contract with the U.S. Department of Energy, the new centers will be located at Lawrence Livermore National Laboratory and Oak Ridge National Laboratory and will focus on development of the forthcoming Summit and Sierra supercomputer systems, which are expected to be delivered in 2017. The Summit supercomputer will be housed at Oak Ridge, while the Sierra will be situated at Lawrence Livermore; both are due to become operational in 2018.To read this article in full or to leave a comment, please click here

US to begin talks on drone privacy standards

A U.S. government agency will start its third attempt to develop voluntary privacy standards for an emerging area of technology, this time with a series of meetings on drone privacy scheduled to begin Aug. 3.The U.S. National Telecommunication and Information Administration has already hosted similar discussions on mobile app privacy and facial recognition privacy but with mixed results. Privacy groups pulled out of the facial recognition discussions in June, saying the process wouldn’t lead to enough protections for consumers.To read this article in full or to leave a comment, please click here

The 10 most powerful supercomputers on Earth

The biggest supercomputers out thereThe twice-yearly top500 listing of the world’s most powerful supercomputers is out, and even if there are few surprises, the presence of a brand-new system on the top 10 is intriguing. Here’s your illustrated list of the 10 mightiest computing machines on the planet, as of June 2015.To read this article in full or to leave a comment, please click here

UK man arrested for stealing half a penny’s worth of power to charge iPhone

As ridiculous as it was when police in Georgia arrested an electric car owner for stealing five cents of electricity, it may be more ridiculous that a UK man was arrested for stealing about a 'penny's worth' of power after charging his iPhone on a train.The entire episode was "ridiculous," artist Robin Lee told the London Evening Standard. He had plugged his iPhone into the train to charge it during a trip that took about "eight or nine minutes" and was then arrested for "abstracting electricity."To read this article in full or to leave a comment, please click here

Oracle extends cloud suite to cover entire order-fulfillment process

Oracle took another step forward in its efforts to bolster its cloud offerings Monday with the launch of two new products designed to help companies conduct their entire order-fulfillment processes in the cloud.Oracle Order Management Cloud and Oracle Global Order Promising Cloud are both extensions of the company’s Supply Chain Management Cloud and aim to provide modern order-management, visibility and fulfillment capabilities.The new Order Management Cloud focuses on order capture and fulfillment with the goal of improving order handling. Among the potential benefits for users are centralized order monitoring and the ability to proactively manage order exceptions. Companies can also define, implement and maintain their own fulfillment policies without the need for technical programming tools, Oracle said.To read this article in full or to leave a comment, please click here

Interviewing for the “Ideal Candidate”: Looking for “Nerdvana” – New Packet Pushers Blog

I was going through a stock photo website the other day and came across a “formula” that was supposed to equal the “perfect job candidate”.  I chuckled a little out loud.  The person sitting next to me looked over at what was on my laptop screen. Paused. Then asked me what I look for when I’m interviewing someone.  What is my “perfect job candidate?”

perfect_job_candidate_136353023

 

 

 

 

 

 

 

…. For the rest please go to Packet Pushers

packetpushers (1)

http://packetpushers.net/interviewing-for-the-ideal-candidate-looking-for-nerdvana/

1 … 3,417 3,418 3,419 3,420 3,421 … 3,859