Internet-based telephone services are growing in popularity, but they're also creating a growing problem with 911 service.
The problem comes when people fail to keep their current and correct addresses updated with their providers. Those who use the service are required to give that information to 911 services.
Dave Politis of Politis and Associates, and a columnist with utahtechwatch.com, says imagine buying a magicJack for your home in Sandy, then taking it on a road trip to California without notifying anybody of the change.
"911 would not be able to find us. They would think we're still in Sandy. So, if we had an emergency and used our VOIP (Voice Over Internet Protocol) phone in San Diego, we'd be in trouble," Politis said.
In fact, there's a good chance you'd be calling a dispatch center back home. Politis' caution: It's your job to keep that information updated with the company.
Dispatch centers, including some in Utah, are working on ways to solve that problem. Most of Utah has what's called an enhanced 911 system, which allows dispatchers to pinpoint the location of a cell phone, but VOIP phones do pose a new challenge.
There are four key steps to deploying QoS for VoIP, and if you don't follow them all, your VoIP implementation will not live up to its full potential. There's a lot more to implementing QoS than just switching on a router feature--so take the time to plan and design the right QoS deployment for your situation. Here are the four steps we have put together along with our colleague John Bartlett.
Step 1: Classify Your Voice Traffic
First you need to select the best scheme to mark packets for priority treatment. Classification involves deciding which streams get waved through and which wait. Everybody wants their applications to receive the highest priority--but if you do that you might as well not bother doing anything. QoS is a zero-sum game involving what gets highest priority and what gets demoted. Because VoIP is real-time and is finicky, you need to give it the highest priority classification.
We recommend mechanisms that enable the network to verify endpoints because when the network can verify that the device at a IP address is a sanctioned IP phone, the router can trust the traffic priority markings that phone provides. In this way, you can protect the network from inappropriate use and the endpoint gets to determine which packets get high priority and which get only best effort support.
Before you mark packets though, we suggest that you create a plan for what traffic will use which service levels, how many service levels there will be, and what markings you will apply to each traffic class. You also need to map your priority classes across the layer 2/layer 3 boundary, and map your priority classes to your carrier's service offerings.
Step 2: Turn On Class of Service (CoS) Mechanisms
Now turn on the mechanisms in your network routers and switches that will implement priority VoIP treatment. The main CoS mechanisms are DiffServ for routed infrastructure, and IEEE 802.1p for switched infrastructure. These mechanisms are embedded into network infrastructure, just waiting to be switched on if they are not already on. You should find turning them on is easy. You can enable CoS through commands in the router and switch configuration files.
Step 3: Plan and Manage Your Bandwidth
Next, you'll need to understand, plan for, and manage your bandwidth. You will find that DiffServ and IEEE 802.1p are not full fledged QoS mechanisms. They provide different levels of service, but they don't address oversubscription. For that you need other mechanisms to ensure that you don't oversubscribe your classes of service because voice quality will suffer.
Delivering good VoIP service quality requires you to estimate the number of simultaneous calls you expect. Then you need to assess whether the available bandwidth will support projected demand, or if you need more. At this point financial reality will inevitably kick in because your budget probably won't support all the bandwidth you need everywhere. So you'll have to manage the number of users who can simultaneously access the bandwidth. In addition, you will need the same type of feedback that the public switched telephone network (PSTN) gives when there is not enough bandwidth for a call. Think of it as the VoIP equivalent to a ‘trunk busy' signal.
IP-PBXs have this function built in. They know about the network topology and they have parameters to determine how many simultaneous voice calls are allowed between locations. When the limit is reached, the IP-PBX either gives the next caller a busy signal, or routes the call to another path (like the PSTN).
Step 4: Monitor VoIP Performance
In the final step, you need to monitor performance to know if your network is providing high quality transport for voice streams and high quality voice reproduction. If there are problems, you need to know before your users get irked. Because voice has special needs, you need new types of monitoring tools--so next week we will give you a thumbnail sketch of those tools.
Skype didn't hear back from Apple soon enough about receiving approval of their WiFi based iPhone app is my guess so they went with what some would consider a bigger gun. Nokia.
Today at Mobile World Congress Skype announced that the next pre-load of Skype will be with Nokia on the Q3 release of the Nokia N97, a very hot device that Nokia first unveiled last December at Nokia World.
One of the things that was obvious is that Skype has learned a lot from their SkypePhone partner, iSkoot, and the iSkoot created client that comes pre-installed and th server that sits inside the carrier network. That intellectual capital was espoused by Josh Silverman who rattled off all kinds of stats related to the 3 customer, many of whom are Skype users, who chose to switch.
Basically the underlying message the Skype CEO shared was carriers who will work with Skype will pick up users who spend more money than the non-Skype using mobile phone customer, or at least they did with 3.
One more note. With services like Skype coming out on the new Nokias, and an already existing Skype-Boingo relationship, and an existing Boingo client already running on the N and E series phones, one doesn't have to start seeing the alignment that is going on, and its all very smart and well thought through on all of the companies parts.
The next installment of the Suzuki Electric Bike Build is up for our enjoyment. You probably remember that last time the motor was getting rebuilt.There is lots of progress being made and as usual there is a video that will take you along the process. Hopefully it will open your eyes to some creative part building techniques. Below is just a bit of the experimentation that was needed to make the custom duct that is used to cool the motor.
"Some PVC 4" sewer pipe, resin, fiber glass cloth, 1/8" hobby plywood, steel strapping, a pair of matching 12Vdc fans, and some cardboard (pop cases) to make templates. It was tricky to mold the manifold against the motor to approximate the angle of air-flow relative to the slot. It had to be done twice, because I used engine oil on the surface of the motor to act as a releasing agent. But the end result was that the resin couldn’t harden, as if the oil was a neutralizer on the catalyst. The second attempt was successful by masking the CLEAN motor surface with Duct Tape."
My daughter seems to have everything that has a Hannah Montana brand on it but I haven’t seen this photocube yet. It’s probably a good thing since after reading about this Hacked Hannah Montana Photocube I would probably have it in a bunch of pieces on my workbench.
"A 1Mb A29L800( datasheet ) flash chip and a micrcontroller hidden behind a big black blob along with the LCD, buttons, USB port and an on-off switch. With some reading on Sprite’s blog and modifyng his script a little, I was able to verify that the microcontroller was indeed a ST2205U. If you browse through main.c, a function is_photoframe checks if the controller is a ST2205U. So I inserted a printf(”Response : %s\n”,buff) to verify if the chip gave back the correct string, which it did."
The title lies a bit, this clock can keep track of all sorts of time zones and events. Sometimes having some extra hardware around looking for a purpose leads to cool gadgets. Have a look at how the Mars Clock was made. Code, schematics and everything else you need to make your own is provided.
"You are probably thinking "There are hundreds of PIC clocks on the Net - do we need yet another one?!" Well, this one is a bit different:
* It has 16 timers that can be independently paused and restarted, and can run forward or backward.
* There are 16 alarms with configurable sounds and actions.
* Timers can show Earth, Mars, Jupiter, etc. times at the same time.
* How about sidereal time, Moon phase, Jupiter’s Great Red Spot transit time, and anything periodic in general?
* Simultaneous 24-hour and Julian-time decimal display.
* All changes in configuration can be done from the device’s keyboard - no computer necessary.
* External AC power with built-in rechargeable battery, so you can take the clock around.
* High on the geekness scale."
A new type of phone directory that provides access to reverse phone number lookups offers users the ability to lookup the name associated with an unrecognized phone number.
For quite some time now, computer users have been able to use online versions of the Yellow and White Pages to look up personal and business listings, but what sets reverse cell phone searches apart from these traditional directories is the fact that they can be used to lookup phone numbers when a person does not have a mysterious caller’s name available.
These very specialized searches are not much different form a normal query performed on an internet search engine. To perform a search, a user must enter a 10-digit phone number into a reverse phone directory’s search field and press enter to retrieve a report containing the phone owner’s name and any extra available information.
The reason why reverse phone search directories are such an effective tool in the battle against unwanted and unsolicited phone calls is that they lift the veil of protection from anonymous callers so that real name and alternate contact information can be gathered immediately.
If you’ve ever tried to call back a telemarketer by dialing the phone number that appeared on your caller identification box, you have probably gotten a recording, or in some cases, the call probably didn’t even go through. By performing a reverse cell phone search on that number, users can find out who the number belongs to before answering the call.
If you have tried to contact a telemarketing firm without the necessary information before, you know how frustrating it can be to remove yourself from call lists. They always claim they will remove your information in a few days, but the calls never seem to stop coming, often times even more frequently than before. However, when you know the name of the company responsible and you have their direct line, you will likely notice a quick end to unsolicited phone calls.
If you are already listed on a Do Not Call list, the unsolicited calls you receive are considered illegal and the company responsible could be subject to large fines. In these cases, a reverse cell phone directory can play a major role in helping to screen your calls effectively.
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