I’ve recently been in quite a few meetings where the acronyms WDM and DWDM have been used. Now I know what WDM is wavelength division multiplexing, but I didn’t agree with them being swapped in and out as one is different from the other.

OK WDM is straight forward enough; Multiplexing is used To combine multiple signals (analogue or digital) for transmission over a single line or media. In the case of the media being fibre, then WDM is used whereby each signal is assigned a particular wavelength.

WDM is the optical equivalent of FDM, short for frequency division multiplexing, a multiplexing technique that uses different frequencies to combine multiple streams of data for transmission over a communications medium. FDM assigns a discrete carrier frequency to each data stream and then combines many modulated carrier frequencies for transmission. For example, television transmitters use FDM to broadcast several channels at once.

DWDM is short for Dense Wavelength Division Multiplexing, an optical technology used to increase bandwidth over existing fibre optic backbones. DWDM works by combining and transmitting multiple signals simultaneously at different wavelengths on the same fibre. In effect, one fibre is transformed into multiple virtual fibres. A key advantage to DWDM is that it’s protocol- and bit-rate-independent. DWDM-based networks can transmit data in IP, ATM, SONET /SDH, and Ethernet, and handle bit rates between 100 Mb/s and 2.5 Gb/s. Therefore, DWDM-based networks can carry different types of traffic at different speeds over an optical channel

So for networks where VoIP is requirement then from a QoS standpoint, DWDM-based networks create a lower cost way to quickly respond to customers’ bandwidth demands and protocol changes.


If you’ve been wondering where I’ve been, I’ve been helping out on a large deal (read over a billion dollars), I’m working on the contracts with 3 major telecoms providers within the UK. I’ve been working out of one of our locations in London, so have been stating over in a Moat house hotel near by.

The deal involves direct fibre connectivity, MPLS, DSL and ISDN, so there’s a few interesting technologies to connect together in there.

I’ve picked up a few new terms, so I’m gonna spend some time catching up on what exactly’s invovled.

Convergence in the wrong direction

This story from The Register is interesting or the last sentence is, “It will help counter fears that Voice over IP calls are draining revenue away from fixed-line provider

The article suggests that Telco’s are thinking that, by converging mobile with fixed line telephony, they’ll be able to protect their market share and maintain their revenue source. It’s a pretty feeble attempt to try and hang on to something that is clearly going to decrease in size. As mobile bandwidth increases and network availability grows, subscribers are going to ditch their fixed lines in droves (and now with naked DSL, there’s no need for a fixed line for internet access either). I don’t think by converging fixed and mobile will stop the consumers moving to a purely mobile position.

It’s also interesting that Orange hasn’t joined (wasn’t invited, but they are owned by France Telecom) neither has vodafone. So it’s clear it’s the companies with the fixed telephony businesses driving the group. The Mobile networks aren’t interested, as they don’t see this as a threat to them in any way shape or form. It’s also interesting the none of the Telco’s that have mobile arms are in the group either (France Telecom or Deutsche Telecom)

I think a more interesting route for them to have taken is to develop an offering that uses GSM/3G when out and about and wi-fi when at home (or near a hotspot). That’s a much more risky situation for the Telco’s though, as it would be admitting that VOIP is cheaper than traditional fixed line telephony.

Convergence is good and it’s what we want, but it’s convergence of technologies that move us forward that we want not convergence of old and new.

Where’s the Mobility

Russ Beattie has started the mother of all discussion over at his blog. He’s upto 40 comments already, that’s a number I’ve never seen before (i’m sure someone will point me at an even more commented upon post though ;-))

He’s have a dig a Silicon Valley and it’s lack of focus on thing’s mobile and some big hitters have waded in with comments, Dave Winer, Kevin Werbach etc.

BT stuffing up NHS contract

BT have today had to pay the NHS a six figure sum, for missing a couple of deadlines. Even though BT have had to stump up the cash, both sides report that everything is rosy. Yeah I bet, BT are probably steaming, this is a big contract for them and it’s in the press they’re messing up..not good PR. But if they are paying out those some in the early days, what must the penalties be like towards the critical end of the project..ouch!.

BT are under huge pressure and Talk Talk has vowed to take more customers away from them in the stronghold of the domestic market. It was also reported in yesterdays Guardian that BT had frozen it’s exec’s pay. BT has a big battle on it’s hands to hang on to the customers it’s got.

I’m sure there’ll be more good news for them in the coming weeks though.

New Treo firmware

Just running the through the process of upgrading the firmware on my Treo 600. Fingers crossed it all goes to plan, upgrading firmware is an operation that always gives me goosebumps.

If you’ve got a Treo 600 on Orange you can find the update app here

VNO cont.

Broadwatch backs up my points about the likes of the VNO’s trying to steal a march on the big hitters in the industry.

But while Muirhead is optimistic that the Nexagent approach of flexible, multisourced VPNs suits all parties, the company faces tough competition in the form of the incumbent international VPN providers, all of which have their eyes on capturing as much of the growing enterprise IT budgets for themselves.

At a recent London carrier event, Cable & Wireless plc (NYSE: CWP), Global Crossing Holdings Ltd. (Nasdaq: GLBC), MCI (Nasdaq: WCOEQ, MCWEQ), and Sprint Corp. (NYSE: FON) were all pushing their credentials as premium providers of single-sourced international VPNs.

In addition, AT&T Global Network Services, BT Global Services, Equant (NYSE: ENT; Paris: EQU), and Infonet Services Corp. (NYSE: IN) are all heavy hitters that continue to sign new VPN customers — and they’ll want to keep the lion’s share of revenues, and customer control, to themselves.

BTW Charlie Muirhead was 28 when he setup Nexagent…cripes!

Get a Grip!

I totally, agree with Robert Hamilton here (MMS to Landlines)…MMS isn’t exactly causing the cash tills to overflow. Do they seriously expect us all to go out and buy new (proably v.expensive with colour displays)fixed line phones? Most people using this technology aren’t exactly Luddites, so will probably have email where they can receive the pictures anywhere. Yes please Siemens and Alcatel, I want to buy yet another v.expensive phone and be tied to a cord to receive pictures! …er sorry for ranting but people rightly do need to get a grip.