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Category Archives for "Networking"

Arduino: Using my MelodyUtils library for R2-D2 style chirps

As part of a small robotics project I've been working on this weekend (affectionately called CoBe1, there will be a follow up blog on that soon) I decided to give by robot some personality in the form a a voice, and uploaded some of my code to GitHub.

While Arduino is capable of playing music and sounds from an SD Card I wanted something a little more authentic… something similar to R2-D2's chirps from Star Wars. I had a mini 8Ohm speaker lying around and following the tutorials here it was easy to get it hooked up to my Arduino Uno and start making sounds. By adjusting the default melody and timings I got part way to achieving my R2-D2 style attitude, but notes on their own just didn't cut it. What I needed was some articulations. I got coding and whipped up a library that makes it easy to use glissando and tremolo. Want to give it a try? Grab the code on GitHub Here's a simple example sketch:

#include <pitches.h>;

void setup()
{
MelodyUtils mel(8);
mel.Glis(NOTE_C3, NOTE_C4, 5);
delay(1000);
mel.Trem(NOTE_C3,  Continue reading

Multi-Vendor OSPF Cost Calculations

While on my current kick with virtual routing, I stumbled across an interesting concept regarding OSPF, and the flexibility that vendors have in determining the best path through an OSPF network. The following topology is what I’ve been staring at for the last few days Pretty simple, right? There’s a single network (192.168.123.0/24) down inside each virtual host where the VMs are to sit. Each host has a router on it (one Cisco CSR 1000v and the other Vyatta Core 6.

Multi-Vendor OSPF Cost Calculations

While on my current kick with virtual routing, I stumbled across an interesting concept regarding OSPF, and the flexibility that vendors have in determining the best path through an OSPF network. The following topology is what I’ve been staring at for the last few days Pretty simple, right? There’s a single network (192.168.123.0/24) down inside each virtual host where the VMs are to sit. Each host has a router on it (one Cisco CSR 1000v and the other Vyatta Core 6.

HP Route Preference (Administrative Distance)

When building networks leveraging a variety of products you need to consider interoperability and configuration consistency. When leveraging HP A-Series switches in a Cisco environment considerations need to be made in regards to administrative distance (Cisco's term) or route preference (HP's term). In order to ensure that you maintain consistent behavior it is recommended that you modify one or the other and make them consistent with each other. I would recommend following Cisco's administrative preference instead of HP's route preference.

HP's default route preference



Cisco's default administrative distance


Don't get caught with unexpected routing behaviors. Have fun!

What The Heck Is F5 Networks’ TMOS?

F5 Network’s Traffic Management Operating System (TMOS) is, first and foremost and for the sake of clarity, NOT an individual operating system. It is the software foundation for all of F5’s network or traffic (not data) products; physical or virtual. TMOS almost seems to be a concept rather than a concrete thing when you first try […]

Author information

Steven Iveson

Steven Iveson

Steven Iveson, the last of four children of the seventies, was born in London and has never been too far from a shooting, bombing or riot. He's now grateful to live in a small town in East Yorkshire in the north east of England with his wife Sam and their four children.

He's worked in the IT industry for over 15 years in a variety of roles, predominantly in data centre environments. Working with switches and routers pretty much from the start he now also has a thirst for application delivery, SDN, virtualisation and related products and technologies. He's published a number of F5 Networks related books and is a regular contributor at DevCentral.

The post What The Heck Is F5 Networks’ TMOS? appeared first on Packet Pushers Podcast and was written by Steven Iveson.

Show 144 – Open EIGRP with Russ White + Cisco’s Donnie Savage

EIGRP is a distance vector routing protocol that for many years was unique to Cisco networking environments. Created and championed by Cisco, it didn’t get any traction in the standards bodies in the early days, because there were already enough interior gateway routing protocols around according to some. EIGRP just didn’t interest enough of the […]

Author information

Ethan Banks

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

The post Show 144 – Open EIGRP with Russ White + Cisco’s Donnie Savage appeared first on Packet Pushers Podcast and was written by Ethan Banks.

[Virtual Routing] Part 2 – FHRP Issues in VMware vSphere

I was working on a topology for another post regarding interoperability between the recently released Cisco Cloud Services Router (CSR 1000v) and Vyatta when I ran into an issue regarding vSphere network security policies and First Hop Redundancy Procotols (FHRP) such as VRRP. This post will serve as a precursor to that overall post, but I want to point out a key configuration piece when performing redundant gateways with a FHRP like VRRP.

[Virtual Routing] Part 2 – FHRP Issues in VMware vSphere

I was working on a topology for another post regarding interoperability between the recently released Cisco Cloud Services Router (CSR 1000v) and Vyatta when I ran into an issue regarding vSphere network security policies and First Hop Redundancy Procotols (FHRP) such as VRRP. This post will serve as a precursor to that overall post, but I want to point out a key configuration piece when performing redundant gateways with a FHRP like VRRP.

[Virtual Routing] Part 2 – FHRP Issues in VMware vSphere

I was working on a topology for another post regarding interoperability between the recently released Cisco Cloud Services Router (CSR 1000v) and Vyatta when I ran into an issue regarding vSphere network security policies and First Hop Redundancy Procotols (FHRP) such as VRRP. This post will serve as a precursor to that overall post, but I want to point out a key configuration piece when performing redundant gateways with a FHRP like VRRP.

Cisco Nexus – Port “Inactive” Status

Quick notes on the “inactive” port status seen on the Cisco Nexus platform, which was perplexing the first time I ran into it. This isn’t a new status, existing on a variety of Cisco platforms for a long time now. As it happens, I’ve just not seen it that often historically. In dealing with the […]

Author information

Ethan Banks

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

The post Cisco Nexus – Port “Inactive” Status appeared first on Packet Pushers Podcast and was written by Ethan Banks.

Packet Design Appoints Matt Sherrod as Vice President of Product Management

Company Snags Network Management Expert and Industry Veteran

SANTA CLARA, CA — April 16, 2013 — Packet Design, the leading provider of IP network route analytics software, announced today that it has hired Matt Sherrod as Vice President of Product Management. Sherrod will lead product strategy, product design and integrated partner solutions to expand the Packet Design product portfolio and deliver a best-in-class customer experience.

Sherrod has more than 25 years of networking experience. He joins Packet Design from CA Technologies where, as the Vice President of Product Management, he defined product direction and strategy for the company’s infrastructure management solutions. Over the last 10 years he has held a number of field and management positions at CA Technologies and NetQoS. Prior to joining NetQoS, Matt worked as Director of Communications for a Fortune 100 global enterprise, applying leading edge technologies to improve application delivery.

“Matt Sherrod has a deep understanding of customer needs coupled with years of experience in defining and delivering innovative network performance management products to address them,” said Scott Sherwood, CEO of Packet Design. “He is uniquely qualified to lead Packet Design’s product strategy and ensure we provide world-class management solutions for complex service provider and Continue reading

[Virtual Routing] Part 1 – CSR 1000v First Glance

As some of you have heard, the Cisco Cloud Services Router (CSR) 1000v has recently been released for download, and I quite literally pounced on it when I first heard the word. For those that haven’t heard, the CSR 1000v is essentially Cisco’s answer to the problem that has existed in datacenters for a while - that the current multi-tenancy mechanisms, especially overlays like VXLAN and yes, even NVGRE, are just not cutting it for everyone.

[Virtual Routing] Part 1 – CSR 1000v First Glance

As some of you have heard, the Cisco Cloud Services Router (CSR) 1000v has recently been released for download, and I quite literally pounced on it when I first heard the word. For those that haven’t heard, the CSR 1000v is essentially Cisco’s answer to the problem that has existed in datacenters for a while - that the current multi-tenancy mechanisms, especially overlays like VXLAN and yes, even NVGRE, are just not cutting it for everyone.

[Virtual Routing] Part 1 – CSR 1000v First Glance

As some of you have heard, the Cisco Cloud Services Router (CSR) 1000v has recently been released for download, and I quite literally pounced on it when I first heard the word. For those that haven’t heard, the CSR 1000v is essentially Cisco’s answer to the problem that has existed in datacenters for a while - that the current multi-tenancy mechanisms, especially overlays like VXLAN and yes, even NVGRE, are just not cutting it for everyone.

The Route to Null0 is OK

Back to the basics today. I have seen this pop up a few times and wanted to offer some clarification on what seems to be a cloudy issue for CCNP (and some CCIE) candidates. I’ve seen quite a few times now where engineers see a route to Null0 in a Cisco router and assume instantly that the router is “black holing” traffic.   Sometimes, a route to Null0 is inserted into the routing table when performing summarization with nearly every routing protocol in common use today.

KIClet: SDN – Pick Your Poison

I keep having to remind myself that SDN is more about solving a policy problem than a transport problem. This is why the answer to the question “Will SDN solve all of our networking problems?” is always NO. Truth be told, SDN has been around for a while (see SNMP, Perl, Netconf) in various forms, but it’s receiving a lot of attention right now because the mechanisms are starting to mature and frankly, the networking industry hasn’t really seen a lot of groundbreaking innovations lately.