Understanding CME Overlays with Dual-Line DNs

Normally I talk about overlays in the context of data center/SDN/cloud but today I’m going out into left field and am going to talk about voice! :-)

I freely admit that I’m a noob when it comes to Cisco voice so I’m not sure if the behavior I’m about to describe is obvious or not. It wasn’t obvious to me and I only figured it out after running into the issue for real and troubleshooting it to resolution.

The issue stems from my misunderstanding about how dual-line ephone-dns function when used in an overlay.

The Desired Behavior

Here’s the scenario: Cisco Communications Manager Express (CME) with a handful of IP phones registered to it. There’s no Communications Manager (UCM); the dial plan lives entirely within CME. PSTN connectivity is via (4) POTS lines terminated on FXO ports on the router running CME.

The desired behavior is to have incoming calls from the PSTN ring on all the IP phones simultaneously. If a second call comes in, it should ring on all the remaining phones, and so on.

The Original CME Config

Here’s what the original CME config looked like. At least, the parts of the config relevant to this blog Continue reading

10 Tips for Daily Time Management

Those in technology realize that a day of work can vary greatly and can change without warning. Additionally, many try to build elaborate project plans and organizational goals. However, what is sometimes overlooked is the importance of daily execution of tasks. Those in technology must individually address the need to stay on task each and […]

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Paul Stewart

Paul is a Network and Security Engineer, Trainer and Blogger who enjoys understanding how things really work. With nearly 15 years of experience in the technology industry, Paul has helped many organizations build, maintain and secure their networks and systems. Paul also writes technical content at PacketU.

The post 10 Tips for Daily Time Management appeared first on Packet Pushers Podcast and was written by Paul Stewart.

Understanding CME Overlays with Dual-Line DNs

Normally I talk about overlays in the context of data center/SDN/cloud but today I'm going out into left field and am going to talk about voice! :-)

I freely admit that I'm a noob when it comes to Cisco voice so I'm not sure if the behavior I'm about to describe is obvious or not. It wasn't obvious to me and I only figured it out after running into the issue for real and troubleshooting it to resolution.

The issue stems from my misunderstanding about how dual-line ephone-dns function when used in an overlay.

Show 162 – The Bourbonator Rises at #NFD6

The mostly nonsense title masks several discussions we have with many of the Networking Field Day 6 delegates around the following topics: Spirent’s new Avalanche NEXT testing platform for network transit and security platforms. What it is, what it does, and what we thought of the live demo we got. Our introduction to the ThousandEyes […]

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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 2M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks

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The post Show 162 – The Bourbonator Rises at #NFD6 appeared first on Packet Pushers Podcast and was written by Ethan Banks.

Finding a New Path (Part 2)

So –we’ve covered on of the two cases dealing with calculating a new path, and then I left you hanging for a week. What’s the second case? Let’s return to our small network for a moment to figure it out. What happens if D’s cost to reach the destination isn’t lower than E’s cost? E […]

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Russ White

Principle Engineer at Ericsson

Russ White is a Network Architect who's scribbled a basket of books, penned a plethora of patents, written a raft of RFCs, taught a trencher of classes, and done a lot of other stuff you either already know about, or don't really care about. You want numbers and letters? Okay: CCIE 2635, CCDE 2007:001, CCAr, BSIT, MSIT (Network Design & Architecture, Capella University), MACM (Biblical Literature, Shepherds Theological Seminary). Russ is a Principal Engineer in the IPOS Team at Ericsson, where he works on lots of different stuff, serves on the Routing Area Directorate at the IETF, and is a cochair of the Internet Society Advisory Council. Russ will be speaking in November at the Ericsson Technology Day. he recently published The Art of Network Architecture, is currently working on a new book in the area Continue reading

‘Dark Horse’ Networking – Private Networks for the control of Data

Next Generation Virtualization Demands for Critical Infrastructure and Public Services

Introduction

In recent decades communication technologies have realized significant advancement. These technologies now touch almost every part of our lives, sometimes in ways that we do not even realize. As this evolution has and continues to occur, many systems that have previously been treated as discrete are now networked. Examples of these systems are power grids, metro transit systems, water authorities and many other public services.

While this evolution has brought on a very large benefit to both those managing and using the services, there is the rising spectre of security concerns and the precedent of documented attacks on these systems. This has brought about strong concerns about this convergence and what it portends for the future. This paper will begin by discussing these infrastructure environments that while varied have surprisingly common theories of operation and actually use the same set or class of protocols. Next we will take a look at the security issues and some of the reasons of why they exist. We will provide some insight to some of the attacks that have occurred and what impacts they have had. Then we will discuss the traditional Continue reading

RIP &#8211 Auto Summarization and Impact on Discontiguous Networks

This article discusses the solutions for quiz 15. Yes, I know, I know... it's about RIP ! But you need to be ready for anything when facing the challenges of a CCIE exam. Read along to review some things about auto-summarization (which is "on" by default).

RIP &#8211 Basic Configuration on Juniper

This article is a continuation of previous post about RIP Auto-Summarization and it's impact on discontiguous networks in Cisco networks, but this time from Juniper's perspective. Using the default auto-summary on Cisco devices can lead to routing loops in case of discontiguous networks, as shown in quiz 15.

Leading cross-functional teams: foot-in-the-door theory

When I was at Juniper, my job was basically to sell internally those ideas that were deemed so controversial or hotly contested that no one could get them through the corporate machinery. This put me in a position that I was almost always leading cross-functional teams whose members did not directly report to me. I […]

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Michael Bushong

The post Leading cross-functional teams: foot-in-the-door theory appeared first on Packet Pushers Podcast and was written by Michael Bushong.

To Kill a VTP

Ubuntu OVF images for download

Plexxi DSE: An Informal Analogy

Plexxi DSE: An Informal Analogy

Five selfish reasons to interview candidates

Lets be honest. It is hard to justify the time needed to interview people. It can be really hard to motivate yourself to interview potential new hires when project deadlines are looming. It is perfectly fair to ask yourself, “what’s in it for me?” I think there is a payoff for time spent on hiring. […]

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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 Five selfish reasons to interview candidates appeared first on Packet Pushers Podcast and was written by John Harrington.

NFD6 Preview: Solarwinds

NFD6 Preview: Solarwinds

Finding a New Path (Part 1)

In my last installment on the topic of fast convergence, I said I’d be discussing the calculation stage of fast convergence next. Orhan tried to scoop me in the comments, but that’s okay –I’m working at this through the process switched path, rather than interrupt context. In parallel with flooding information about the topology change […]

Author information

Russ White

Principle Engineer at Ericsson

Russ White is a Network Architect who's scribbled a basket of books, penned a plethora of patents, written a raft of RFCs, taught a trencher of classes, and done a lot of other stuff you either already know about, or don't really care about. You want numbers and letters? Okay: CCIE 2635, CCDE 2007:001, CCAr, BSIT, MSIT (Network Design & Architecture, Capella University), MACM (Biblical Literature, Shepherds Theological Seminary). Russ is a Principal Engineer in the IPOS Team at Ericsson, where he works on lots of different stuff, serves on the Routing Area Directorate at the IETF, and is a cochair of the Internet Society Advisory Council. Russ will be speaking in November at the Ericsson Technology Day. he recently published The Art of Network Architecture, is currently working on a new book in the area Continue reading

Show 161 – VMware NSX – Real World SDN – Sponsored

Deep diving on VMware NSX ? You bet. Download the PDF file and read along with us as we unpack how VMware NSX works with Brad Hedlund and Scott Lowe. Network Virtualization is the certainly the biggest architecture shift in our careers and probably yours.  And make no mistake, this is about networking.  Greg Ferro often says that […]

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Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at EtherealMind.com and on Twitter @etherealmind and Google Plus.

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The post Show 161 – VMware NSX – Real World SDN – Sponsored appeared first on Packet Pushers Podcast and was written by Greg Ferro.

Need more capacity: MPC4e cards are there!

Need more capacity: MPC4e cards are there!