The “five nines of reliability” is a term that you’ve likely heard if you’ve been in systems management for any length of time.  The promise of “five nines” is that the system will have a 99.999% uptime over a given period of time, usually a year.

But how much downtime does this leave me in a year?   Check out this useful chart below:

As you can see, 99.999% uptime annually leaves you five minutes for complete systems outages.

Another commonly used metric for measuring availability is Defects Per Million (DPM). While measuring the probability of failure of a network and establishing the service-level agreement (SLA) that a specific design can achieve is a useful tool, DPM takes a different approach. It measures the impact of defects on the service from the end user’s perspective. It is often a better metric for determining the availability of the network because it better reflects the user experience relative to event effects.

Click here to read more about DPM

NetworkWorld.com came out with a great article on the Cisco UCS platform.  If you’re not familiar with Cisco’s bid on the data center and server virtualization space, this is a must read.

I’m becoming increasingly convinced that Cisco UCS product line is going to change the way we view server virtualization.  It’s innovative and brings a tear to this “tech head.”

Integrated server blades, networking and management make UCS a strong contender for fast-growing data centers in this exclusive Network World test.

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Today, I’ve been working on a design document for a customer in Minneapolis.  For this project, we’re rolling out the full Cisco UC 8.6 “iron fist”: CUCM, CUC, CUPS, CER, and CUEAC.

I wanted to define the phone firmware versions for CUCM 8.6(2a), but forgot where to find it.

After 10 minutes of searching, I uncovered the firmware matrix here: Cisco Unified Communications Manager Software Compatibility Matrix.

Search for “Default Loads” (the page itself is length).  Voila.

The matrix shows you the default loads, broken out by CUCM versions. Simple post, but helpful information. Just the way we like it around here!

If you’ve ever deployed Cisco Unified Presence Server (CUPS) or read about Cisco’s CUPC or Jabber clients, you’ve likely run across the XMPP acronym.

XMPP, short for Extensible Messaging and Presence Protocol, is a term every UC (err…collaboration) engineer should become familiar with.  XMPP relates to AIM, GTalk, Lync, CUPS, and iChat (@me.com).

XMPP is maintain by the  XMPP Standards Foundation, which is an independent, nonprofit standards development organization whose primary mission is to define open protocols for presence, instant messaging, and real-time communication and collaboration on top of the IETF’s Extensible Messaging and Presence Protocol (XMPP).

Here’s a brief blurb about XMPP from their website:

The Extensible Messaging and Presence Protocol (XMPP) is an open technology for real-time communication, which powers a wide range of applications including instant messaging, presence, multi-party chat, voice and video calls, collaboration, lightweight middleware, content syndication, and generalized routing of XML data. The technology pages provide more information about the various XMPP “building blocks”. Several books about Jabber/XMPP technologies are available, as well.

The core technology behind XMPP was invented by Jeremie Miller in 1998, refined in the Jabber open-source community in 1999 and 2000, and formalized by the IETF in 2002 and 2003, resulting in publication of the XMPP RFCs in 2004 (see the history page for more details).

Although the core technology is stable, the XMPP community continues to define various XMPP extensions through an open standards process run by the XMPP Standards Foundation. There is also an active community of open-source and commercial developers, who produce a wide variety of XMPP-based software.

If you have any questions about the use or development of XMPP technologies, feel free to participate in one of the open discussion venues hosted by the XMPP Standards Foundation.