Monthly Archives: April 2009

Calculating Bandwidth – VoIP

Typically when deploying VoIP in the enterprise your going to be dealing with G.711 and/or G.729 codecs.  Both of these codecs sample at 10ms intervals.  The default is to usually send packets every 20ms, however in some situations one might see this set to every 30ms.

If your doing packets every 20ms this creates about 50 packets per second.  If your set to 30ms you will be creating 33.3 packets per second.

Lets focus on G.711 for a second.  G.711 has a sample size of 80 bytes.  So if we are set to use the default voice payload freq. of 20ms and we know that samples are taken every 10ms then our G.711 voice payload will be two samples of 80bytes = 160bytes of voice in every packet.

Thats only part of the equation though, you can’t forget about headers!

You will need to know what headers your going to be dealing with such as Layer 2, Layer 3 or both combined? And possibly WAN headers also.

In a typical ethernet packet your looking at about 58 bytes of header overhead.  18 bytes of ethernet (Layer 2) and 40 bytes of IP, UDP and RTP (Layer 3).  So with your 160 bytes of voice and 58 bytes of header overhead your dealing with 218 byte packets.

In this example we are using the default 20ms voice payload freq. which we said corresponds to about 50 packets per second right?  So we take our total packet size of 218bytes x 8bits x 50 packets per seconds = 87.2 Kb/s for every voice call.

What makes us tick?

Ok so if you read this and you don’t know me personally (actually I suspect even those that do know me) may not know that I am fascinated with understanding what makes us who we are.

I think this is just another aspect of a very core component of me and who I am, which is my unquenchable thirst for knowledge.  Not just knowledge for the sake of knowledge and trying to appear smarter than I really am.  My desire is to understand things.  I love to understand everything I can about something.  It makes no difference what it is, I will want to know everything I can about it.

So why do I say all of this?  It’s not about technology this time.  Nope its about us, the human.

I am not as fascinated with the physical side of what makes us who we are as humans.  My fascination is with the behavioural side of what makes us tick.

When I was younger (teenage years and early twenties) I hated psychology.  Pretty vague statement huh? 

Let me elaborate a bit.  In high school I took a psychology class and well I hated it.  Thought it was stupid.  How could anyone believe the crap they were teaching?  How could anyone think they know what makes us tick and make the decisions we make?  And even worst than that was how could anyone tell me that I am not really my own person, that nearly every decision I make was influenced by someone or something?

Thats not exactly what they were saying in those textbooks, but its how I interpreted it.   It really upset me to hear things that implied that a lot of who I am and who I will be is very closely tied to my parents.

I mean come on, I am a teenager.  I don’t want to be associated with my parents.  I want to be independent, I want to think I am my own person.  I make the decisions that make me who I am.

Boy was I wrong!

To be continued….

CCIE Voice Lab – Version 3

Cisco has refreshed / updated the CCIE voice lab.  Listed below is the new equipment and software it will cover.

 

Lab Equipment:

  • Cisco MCS-7845 Media Convergence Servers
  • Cisco 3825 Series Integrated Services Routers (ISR)
  • Cisco 2821 Series Integrated Services Routers (ISR)
  • ISR Modules and Interface Cards

             VWIC2-1MFT-T1/E1 
             PVDM2 
             HWIC-4ESW-POE 
             NME-CUE

  • Cisco Catalyst 3750 Series Switches
  • IP Phones and Soft Clients

Software Versions

Any major software release which has been generally available for six months is eligible for testing in the CCIE Voice Lab Exam. 

  • Cisco Unified Communications Manager 7.0
  • Cisco Unified Communications Manager Express 7.0
  • Cisco Unified Contact Center Express 7.0
  • Cisco Unified Presence 7.0
  • Cisco Unity Connection 7.0
  • All routers use IOS version 12.4T Train.
  • Cisco Catalyst 3750 Series Switches uses 12.2 Main Train

Network Interfaces

  • Fast Ethernet
  • Frame Relay

Telephony Interfaces

  • T1
  • E1

 

Source:  Cisco Learning Network

Some of the major changes are:

1) Remove analog devices (such as VG248, ATA)
2) Remove CatOS (Catalyst 65xx)
3) Replace CCM with CUCM 7 (Linux Appliance)
4) Replace Unity with Unity Connection 7 (Linux Appliance)
5) Add CUPS 7 (Linux Appliance)
6) Add SIP phones

Basic topology:

ccie_voice_v3_topo

 

Source:  http://htluo.blogspot.com

Future of Cable Providers?

What does the future hold for cable providers?  I don’t know, but I do have some ideas.  I don’t claim to be an expert on any thing related to cable companies and I am not speaking for any one provider in particular.

I am personally very new to the cable industry, especially compared to just about everyone I have met since going to work for a provider.  However I am not new to technology and keeping up with the latest and greatest in tech trends.  One thing I have noticed over the years is the often we ‘geeks’ are lucky in that we often get a glimpse into the future without always knowing it.

What do I mean by that?  Well basically we tend to get our hands on or read about the latest technologies before they ever go mainstream.  And during this time its sort of like a glimpse into the future when you consider how few overall know about or have experience with these things.

Cable providers in general have sort of had it made in the past.  Competition was weak at best and cable for the longest time was the future.  So much has been done and so much remains to be done over that single piece of coax, but I think everyone can agree that its future is limited in the traditional sense.  How far out is a question that is highly debateable and I surely don’t want to get into.

Locally people are going to associate what I am saying with fiber, but thats not at all where I want to go with this.   Nope I am thinking a little broader in scope to be honest.  Why?  Because I am not concerned with the physical layer of things.  I know the physical layer can and will likely change over time.   And regardless of the physical layer cable providers still have to some how differentiate themselves and the services they offer.

The physical layer is not where one makes money.  Anyone can provide that.  Where you make money is in how you use that physical layer and what services are offered over it.

I think everyone can agree that the future boils down to two letters.  IP

Everything you can do over the traditional cable plant can be done over any type of physical layer as long as IP is involved.

What I find to be the most significant point about all of this is the fact that you can do this technically with no regard to whose providing the physical layer which also means you can provide your service to those outside of the typical cable providers physical plant.

The cable industry is always looking for ways to reach more homes, and always talk about “homes passed” and “RGU – revenue generating unit”. 

I am very surprised that the cable providers aren’t pushing themselves a little harder to become more of a “service provider” rather then just a “cable provider”.  Seems the focus should be on transitioning their services to be more IP based with the goal of providing the service to anyone who wishes to subscribe regardless of where or with whom the customer gets their physical connectivity with.

The cable industry more so then any other should be able to do this quickly and effectively.  Most have the backbone and pipes to provide this sort of service.  They already have the headends and MTC’s for obtaining the content from the content providers.  They have been working with and dealing with the hassle of negotiating contracts for content for years.  They typically have data engineers and experience on that side of things, including knowledge of switched digital or IPTV.  They have all these building blocks or pieces of the puzzle but they just don’t seem to be putting it together with the same end goal.

They seem to focus on doing all of this but stuck on doing it over their physical plant.  I personally think this might have a lot to do with the fact the industry is aging, including all of the experts and leadership.  What I love the most about the industry (the fact that their are so many people who have been in it longer than I have been alive) I fear is also what holds it back often.

A couple of years ago I shared with some friends my idea that I eventually blogged about as well regarding the creation of a media device that was easily configured to the individual users IP services (VoIP, Video and so on) that would not care about who provide the data pipe.  I liken it to a cross between your current cable box, Xbox or Apple TV, SIP phone and so on.  You can read a little about that here:  http://bit.ly/19WjKZ

This idea falls right into line with what I am talking about now and where I think the cable providers need to focus on heading to sooner then later. 

Here is a quick recap and what I personally think should be happening:

  1. Become an IPTV provider.  Example is to partner with someone like Microsoft where users can subscribe to an IPTV service through their XBox or PC.
  2. Become a VoIP provider.  Look at Vonage as example.  Offer a SIP service offering where anyone can signup to get a local phone number and VoIP service which could be tied to a SIP phone of SIP softphone client.
  3. Keep improving your customers data side.  DOCSIS 3 sooner than later.  Realize that this (big bandwidth) is the future and the foundation for which all things will be based on including your own service offerings (see items #1 and #2 above).
  4. Let go of these “walled gardens”.  Mr. Cable Provider, tear down this wall!  Seriously, its time to let go.  You have the potential to be so much more and your “homes passed” can become anyone with high speed internet and not just those directly connected to your plant.
  5. Push the device manufactures and the CableLabs to start working on that dream device I mentioned.  It needs to be something based on a standard (like SIP).  See my post here for more details:  http://bit.ly/19WjKZ

Sorry for the long dissertation.  I write too much I know in my poor attempt at trying to get these ideas out of my head in a way for anyone to understand.  I am not talking about anything new here or revolutionary, but as many would say this is all evolutionary.

I hope in a few years I can look back on this and know that others in the industry were way ahead of what I give them credit for and already were working on all these things.

Cox launches DOCSIS 3 in Lafayette

Not sure if others saw this yet, it just got released from what I understand.

Now I know most in the City of Lafayette aren’t going to care much
about this due to LUS fiber slowly becoming available. But some others
around the Lafayette area outside of LUS planned rollout might.

My understanding is that the first plan is $89 a month for 50down/5up.
 I know I know.. 5up, lets just say its better than what Cox has been
offering so thats a good start.  :-)   There is also a $99 charge I
believe for the cable modem, I think you have to buy it outright from
Cox.  The modem in question is a Cisco DPC3000.

I think it is now ok to share that I have been testing it for about a
month now and so far so good.  Consistently get the speeds stated.

I know this isn’t for everyone, and I don’t want to get into the
arguments of what service is better and blah blah.  However, I should
point out if you look at the rest of the cable industry that has
rolled out DOCSIS 3 you will find that the prices are WAY higher than
the $89 that they are charging here in Lafayette.

To me this is a win for the Lafayette area.  And it sort of falls
right into line with what the fiber folk wanted in some ways which was
to push the incumbents to do and offer more to the area.  So I would
think even they should be somewhat happy with this in a way.

Should be particularly good for those ‘work at home’ folk who often
have the service paid for buy the company.  The better upload is
significant when compared to any of the current Cox offerings.

Here is the official press release:

FOR IMMEDIATE RELEASE: April 1, 2009

COX CONTACTS:
Patricia Parks – Cell: (337) 254-0341 – patricia.parks@cox.com
Ann Ruble – Cell: (225) 317-1807 – ann.ruble@cox.com

GREATER LOUISIANA IS FIRST NATIONAL MARKET TO LAUNCH COX’S ULTIMATE PACKAGE

Cox’s Lafayette Parish residential customers first in Cox’s national
footprint to receive speeds up to 50 Mbps through DOCSIS ® 3.0
Technology

Cox Business customers in Lafayette Parish also see first launch of
Cox Business Internet Ultra tier

LAFAYETTE / BATON ROUGE – Cox Communications today announced that it’s
launching the Ultimate Cox High Speed Internet Package in Lafayette
Parish, Louisiana including the cities of Broussard, Carencro, Duson,
Lafayette, Scott and Youngsville. This is the first market to launch
nationally for Cox. Powered by the strength of the cable industry’s
DOCSIS 3.0 technology, Ultimate Internet offers customers some of the
fastest broadband speeds in the marketplace, with downloads up to 50
Mbps and uploads up to 5 Mbps.

“We’re proud to be the first market where Cox is offering the new
technology of DOCSIS 3.0 to our customers,” stated Jacqui Vines,
senior vice president and regional manager for Cox Greater Louisiana.
“Cox has invested over $500 million regionally in our network
operations to ensure we continue to deliver on our commitment to
meeting customer needs. Our investments – and the talents of our
technical team – positioned us for this first in the nation launch.”

DOCSIS 3.0 is a cable-exclusive technology that allows providers to
combine Internet channels in a new way to offer even faster speeds and
more robust features. While Cox’s Ultimate Internet Package is
designed with the high-end computer user in mind, Cox continues to
offer several other levels of Internet service, for everyone from the
casual e-mail user to the avid music fan who enjoys downloading the
latest hits.

“We know customers are turning to the Internet for more
bandwidth-intensive purposes, such as watching videos online,
downloading music and gaming,” stated Vines.  “Ultimate Internet helps
these customers get more out of what they’re into by doing all these
things in record time.”

Cox Business Internet Ultra, the commercial package powered by DOCSIS
3.0, is also launching to customers in Lafayette Parish. Cox Business
Internet Ultra is the premium package for business customers and
includes download speeds up to 50 Mbps, upload speeds up to 5 Mbps,
five dynamic or static IP addresses, one hosted domain name, and 10
email boxes. While Cox Business has been offering dedicated speeds up
to 100 Mbps through fiber-to-the-premises construction throughout
Greater Louisiana, the Ultra package is the first time customers will
receive speeds of 50 Mbps through Cox’s existing network.

More information about Cox High Speed Internet is available at
www.cox.com/highspeedinternet.

® DOCSIS is a registered trademark of CableLabs. Used with permission.

###

About Cox Communications
Cox is a multi-service broadband communications and entertainment
company with more than 6 million total residential and commercial
customers. The third-largest cable television company in the United
States, Cox offers an array of advanced digital video, high-speed
Internet and telephony services over its own nationwide IP network.
Cox wholly owns and operates the Travel Channel.

Cox’s regional operations in Acadiana and Baton Rouge employ over
1,200 people with an annual payroll of over $45 million. In this
region, Cox serves 311,000 customers with voice, video and data
products in the 13 parishes of Acadia, Ascension, East Baton Rouge,
East Feliciana, Iberia, Iberville, Lafayette, Livingston, St. James,
St. Martin, St. Mary, Vermilion and West Baton Rouge.  Information
about the products and services offered in the combined Louisiana
markets can be found www.cox.com/greaterlouisiana.