Author Archives: Janine Lim

Holiday Hoopla Snowman Swap

Yesterday we finished our almost last Holiday Hoopla Snowman Swap. This was a new TWICE collaborative project and my teachers enjoyed it.

However, the snow really got in our way! The connections were supposed to be the last week in December before school was out for the holidays. The last one I have left is on its third reschedule due to snow & illness. But, none of my teachers have complained. They all comment that there’s still plenty of snow and that the VC is still appropriate!

I’ve enjoyed listening to the discussions of how much snow each school has, whether they have snow days, under what conditions they have recess inside instead of outside, etc.

We had a nice collection of creative snowmen. Here’s a few samples of the pairs:

This one was an Australian snowman! It’s hard to see in this picture, but there is a little kangaroo on his blue pants.

As you can tell, students certainly practiced their descriptive writing skills as well as the skill of following directions! This is a simple videoconference format, yet easily adaptable to many different themes. You too could swap snowmen!

Day 11: How To Dial with a Polycom Remote

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

We have covered the larger issues of setting up and optimizing the network, using gatekeepers, and how to tell people to connect with you via a firewall traversal unit. This week, we are shifting our focus on when you pick up the remote to your endpoint and dial to another site.

Most parts of dialing are straight forward. Enter the numbers and connect. Sometimes, there is a hidden button or a function that changes and it isn’t explained on the official equipment documentation. We are going to share some things that we have learned over the years.

How to Dial

  • Press each number and be sure to enter the “.” after each octet. Dialing a video conference unit is different than dialing a phone, in that you don’t add any “punctuation” in a phone number, but you must on a video conference system.
  • Access the directory, if it is set up, and dial directly from there without entering any numbers.
  • To Dial an Alias: Dial the main IP address, add ## and then the number of the extension, alias, or room number.
  • If you dial an IP address and arrive at a screen and if there is audio, listen to what it is saying to you. Codian bridges are “talky” bridges and will present you with an entry queue or auto-attendant. You can navigate this screen by using the far end camera control on your remote and the the up and down arrow keys. When you arrive at the conference where you should be, press enter.

Polycom ViewStation: Quirk

Remember, when you enter the IP address into the dialing menu, you must enter the “.” between each octet.

  • Older ViewStation remotes had no dot button. You press the red, right arrow key while in the address box. That makes the dot.
  • The call/hangup button is green and does both functions.

Polycom VSX 7000: True Love

This could possibly be our favorite video conference remote of all time.

  • Separate call/end call buttons.
  • Dot button.
  • Separate near and far camera control buttons.
  • Color-coded buttons separating the camera and call functions. (This went away in the HDX remotes.)

Polycom HDX Systems: Tip

Polycom HDX systems came with an entirely new remote design. This design was not made with classroom functionality in mind. It was created to appear attractive in a conference room environment. It takes a bit of getting used to the different shaped buttons and some of the design takes precedence over functionality, in our experience. And it takes more batteries!

If you are accustomed to the Viewstation or the VSX line, those remotes will also work with the HDX line. The color coded buttons on the old remote design were user-friendly and easy to train users on.

Resources

Your Turn

Anything we missed? Can you remember when you first began dialing? What was hard to remember?

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 10: How To Manage Numerous Units Without Losing Your Mind

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

This post is written specifically for those in K12 education who have many videoconference endpoints to support. These are some of the strategies we use to keep our sanity when supporting multiple schools with videoconferencing.

Web Access to Endpoints

If at all possible, have your the districts open up web access to the endpoints (preferably securely to only your IP address/range). With this access you can:

  • upgrade the firmware
  • remotely mute or move the camera
  • remotely place or receive a call
  • update the directory
  • check the status of the unit or the stats on the call

Management Software

All of the major vendors provide management software that can be used to oversee many units. This software usually includes the ability to:

  • Check the status of the unit – is it on etc.? (if SNMP is enabled on the endpoint)
  • Upgrade the firmware
  • Manage phone books on the endpoints
  • Report any problems with the endpoints (remote batteries are low, setting problems, network issues, etc.)

Scheduling Software

While the industry is moving away from a scheduled videoconference environment (to an ad-hoc environment), scheduled calls are still fairly common within K12 education: particularly for shared classes. Depending on the support you provide for your schools, you may find yourself scheduling calls with content providers and partner schools for your teachers. If so, software that schedules and monitors conferences is helpful. All of the major vendors, plus a few others such as Renovo, provide software for scheduling videoconferences.

Database of Contacts

You’ll also want to have an organizational system to keep track of the contact information for people involved in videoconferencing at each of your schools. In Berrien RESA’s schools, the support team includes the main VC coordinator, the principal, the tech coordinator, and sometimes additional staff such as the secretary or media paraprofessional. Keep up to date contact information for everyone:

  • School phone
  • Cell phone numbers
  • Emails
  • Each person’s role

If you have an issue with a school, you want to see at a glance who to contact.

It’s also a good idea to keep up regular communication with your contacts, sharing with them:

  • News and progress about the implementation of videoconferencing
  • Success stories
  • Tips and strategies for promotion
  • Reminders like turning off and securing the equipment for the summer
  • Lists of potential videoconferences to share with teachers

If you don’t have a videoconference contact in each school, you should work on it soon! Here’s what we use to encourage our schools to assign a contact:

Your Turn

  • What have you found helpful and essential in managing a lot of videoconference units? Please share in the comments!

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 9: Gatekeepers: The Good, The Bad, and The Necessary

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

Today we examine the role of gatekeepers in an H.323 video conference environment. Some people view gatekeepers as an essential part of video conferencing; others view them as an annoyance and hindrance. Here’s our collective view of how they work in the K12 curriculum videoconferencing environment.

Why Gatekeepers Are a Pain

For those used to the “old school” method of dialing a straight IP address to VC with another school, gatekeepers can be challenging and frustrating. Here are some of the ways that gatekeepers can cause problems:

  • Older gatekeepers can strip off the extension you’re trying to dial. If you are trying to dial out to someone with one of the firewall traversal systems – an alias and an IP address, sometimes the gatekeeper doesn’t know what to do with the extension. So it strips it off and your call doesn’t work. This seems to happen more often with older gatekeepers.
  • Even if your gatekeeper supports the extension dialing, you can still have problems dialing other schools that are using a gatekeeper. It may not work, or you may not be aware of the method required to call through that other type of gatekeeper.
  • The vendors will tell you to neighbor your gatekeeper with the other school’s gatekeeper, but that is problematic as well. What if you’re participating in Read Around the Planet and have 20 other schools to connect to? What a pain to neighbor to all of their gatekeepers! In addition, the process to neighbor your gatekeeper to another gatekeeper is not easy or intuitive. You’ll probably have to open a trouble ticket with your vendor just to figure out how!

Why Gatekeepers are Awesome

That said, there are some very good reasons to use a gatekeeper!

  • If your network has many videoconference units that connect to the Internet via DHCP, the gatekeeper can assist with dialing. It keeps track of which units are registered to the gatekeeper by serial number, and assigns the same alias to it, no matter where it is on the network. This makes dialing within your network very easy. Even with dialing from outside the network, the alias is consistent which makes it easy for the other site to dial no matter where the unit is inside the network.
  • If you have a limited number of public IP addresses and cannot assign one to each videoconference system, the gatekeeper can provide the public IP address, while the rest of the systems are using an alias registered with the gatekeeper.

Gatekeepers and the Global Dialing Scheme

If your school is on Internet2, you may have support to get your videoconference systems on the Global Dialing Scheme (GDS). Basically, this means your gatekeeper is neighbored into a gatekeeper tree structure used around the world for dialing within the education community. For Berrien RESA, the advantage is the ease with which we can call schools in the UK who are on the JANET network. We have also used this for dialing some schools in Minnesota and Pennsylvania. Unfortunately GDS is used more in higher education than K12. If we were able to adopt it more broadly, it would solve many of the dialing problems we keep addressing in this series.

If you want to get on GDS, here’s what you need to do:

  • First check with the Internet2 contacts in your state/area. It’s likely that you will neighbor your gatekeeper to a state gatekeeper.
  • If there isn’t a strong K12 support for Internet2 in your state, you may need to neighbor your gatekeeper to the Internet2 Commons gatekeeper.
  • If you need help neighboring your gatekeeper, you’ll need the IP address of the gatekeeper you’re neighboring with. Then call your VC tech support and they should be able to help you.

Your Turn

  • Which side do you take for gatekeepers? Essential or a hindrance? Why? Please share!
  • Did we miss anything important in the discussion of gatekeepers? Please add any additional points that shed light on these issues.

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser with input from Lori Colwill. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 8: The Secret of Optimizing the Network for Video Conferencing

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

It is important to understand how H.323 traffic impacts the network and then plan for it. Organizations that do not properly go through this process are often disappointed in the quality of their connections and blame the video conference endpoint, when it is really the network. In today’s post, we’ll examine some other tips to make sure that your network is optimized for video conferencing.

Label the ports in the classroom

One easy system that will make life easier for everyone is to label the ports (Internet jacks) in the classroom so that the teacher knows which one to plug the videoconferencing system into. Schools sometimes have jacks that aren’t live, or one of them is specific for the VLAN, or one of them has the special configurations for videoconferencing.

Label the one that teachers or videoconference coordinator should use. This will reduce support calls and keep everyone happier!

Use a wired connection

A wired connection is more stable and secure than wireless. You’ll get a better quality videoconference if you use a hard-wired connection to the Internet vs. wireless. Videoconferencing is more sensitive than regular data traffic. So give the best you have so that the end users will find the quality acceptable!

If you use wireless, then configure it right!

  • If your wireless connection is configured to be used solely for videoconferencing, then lock it down to the MAC addresses of the videoconference units.
  • If your wireless connection is also used for data, secure it as tight as you can. Avoid scenarios where the other traffic can interfere with the videoconference.
  • Make sure your access points on down through to your switches are configured with the correct variables, i.e. duplexing, line speed, bandwidth restrictions or allows, etc.

Find expert assistance

Work with someone who knows about the technical aspects of videoconferencing. Your usual network support personnel may not be familiar with the intricacies of video. Get the advice of a video conference professional as well!

References

Your Turn

  • Do you agree or disagree with our tips?
  • Do you have any additional tips to share?

We invite your comments and input!

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 7: Working with Your Firewall Traversal Unit

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

Last week we discussed the two main ways to make videoconferencing work on your network. In today’s post, we look a little closer at the firewall traversal solutions.

Firewall Traversal

As a reminder, a firewall traversal box sits on the edge of the network, usually beside the firewall. Video traffic goes through the traversal box, and regular traffic goes through the firewall.

Some choices for this product include:

Benefits

The main reason to acquire a firewall traversal system is to securely pass video traffic through the firewall without reconfiguring your network.

Challenges

The main challenge of firewall traversal units is the problems it causes for receiving calls from other schools and content providers who aren’t on your network.

Working Around the Dialing Challenges

So, let’s say that your network has a firewall traversal unit and you can’t set up your videoconferencing any other way. Here are some tips for managing the dialing problems that will arise in regular use of curriculum videoconferencing. These dialing challenges are due to the necessity of receiving calls from off your network. Unfortunately some vendors and resellers continue to be stuck in the mode of thinking of a closed network, and provide advice to schools that doesn’t apply when they need to receive calls from other schools around the world.

Dial Out
First, realize that in most cases, you may need to dial out to the other site you want to connect to. Generally this isn’t a problem for connecting to content providers, most of whom are set up to receive a call to a direct IP address. However, as more schools use this method to set up videoconferencing, you may find schools you want to connect to who are also set up as dial out only; which means you may not be able to connect to them without using a bridge for you both to dial into.

Dialing Philosophies
Second, realize that Polycom and LifeSize prefer the IP##alias format; and Cisco-TANDBERG prefers the alias@IP or name@domain format. Because the standard isn’t well enough defined here, it leaves room for different implementations.

Polycom
If you have the Polycom Video Border Proxy (previously called V2IU), here are some tips:

  • Make sure it has the setting to translate the @ sign to a # sign. This will make it easier for Tandberg systems to call you.
  • If a newer Polycom system is calling you, they usually can dial the IP##alias format.
  • If a Tandberg system is calling you, have them dial the alias@IP format. (However, older Tandberg remotes do not have the @ sign easily accessible. If they are unable to use their web interface or address book for dialing, you may still have to dial out only to Tandberg sites.)
  • If a LifeSize system is calling you, they can do the IP##alias format.

If none of these work, you’ll have to call the other site or connect through a bridge.

Cisco-TANDBERG
If you have the Cisco-Tandberg Border Controller, here are some tips:

  • Polycom systems can dial the IP##alias format.
  • If a Tandberg system is calling you, have them dial the alias@IP format. (However, older Tandberg remotes do not have the @ sign easily accessible. If they are unable to use their web interface or address book for dialing, you may still have to dial out only to Tandberg sites.)
  • If a LifeSize system is calling you, they can do the IP##alias format.

If none of these work, you’ll have to call the other site or meet on a bridge.

LifeSize
If you have a LifeSize unit behind the LifeSize Transit, here are some tips:

  • Polycom systems can dial in using the IP##alias format.
  • Tandberg systems can dial in using the alias@IP format.
  • LifeSize can dial in using the IP##alias format.

If none of these work, you’ll have to call the other site or meet on a bridge.

References

Your Turn

  • These notes are based on our experiences connecting to schools around the country. If you have further insight to add, please comment!

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser with input from Lori Colwill. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 6: 5 Things That Can Make Your Video Conference Look Horrible

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

VC is a good test of the health of your network. If you have poor or unacceptable video quality, then check for these things:

1. Quality of Ethernet Cable

Make sure you have a good Ethernet cable. No crinks or folds or twists. Make sure it hasn’t been run over by the cart too many times! (For the vendors reading this, yes, this is an issue in K12 schools!)

2. Hubs in the Network Path

Replace any hubs in the path of the video conference traffic. Hubs seriously deteriorate the quality of the connection. Replace them!

3. Filter Settings.

We have all experienced odd behaviors and weird symptoms of videoconferences that ended up being the fault of the filter. Make sure the filter is allowing all necessary traffic to the videoconference systems. Review this port list if needed.

4. Excessive Bandwidth Use Behaviors

One common challenge in bandwidth-starved districts is the use of streaming video tools such as Discovery Education streaming and similar services. On a full-bandwidth network, someone live streaming a video can clobber the quality of the videoconference occurring at the same time. A solution used in Berrien RESA’s service area is to turn off the ability for teachers to live-stream the videos. Instead they must order their videos to be downloaded at night.

Another unfortunate challenge in some districts is that of computer labs used by students without appropriate supervision.

  • Students playing online multi-player games
  • Downloading large software files
  • Downloading large movies
  • Downloading music collections

All these cause havoc on the bandwidth usage.

Do what it takes (technological or political solutions) to make sure that non-academic use of technology doesn’t interfere with real engaging learning experiences.

5. Conflicting Router Settings

10/100 M and Full/Half Duplex Settings
The 10/100M or Full/half duplex settings on the router need to match those settings on the endpoint. When these settings don’t match, the endpoint and the router are constantly negotiating how to communicate and therefore using up processing power and bandwidth, which causes horrible quality. There was a time a few years ago in videoconferencing where it was recommended to hard set both of them to the highest that the router could do. However, with newer routers, generally you’ll get the best success with both set to auto. Experiment to see which works best if necessary.

Timeout Limits
Review the time out limits on the router or the wireless access points. If a call drops consistently after a set amount of time, this could be a timeout limit somewhere in the network path of the videoconference. When the videoconference call starts, the two endpoints communicate on certain ports; but after that, the communication happens on the audio/video streaming ports. In some cases, the router thinks that the connection is no longer being used, so it ends the call. Check the settings!

Cohesive NAT settings
If you’re using the NAT solution, make sure the NAT settings are cohesive on the firewall / router and endpoint. We have all seen situations where the settings are good enough that calls occur, but the quality is poor. Making sure the settings are correct improves the quality. In particular, check the “fixed ports” and “firewall is H.323 compatible” settings. Experiment if necessary to see which settings work best.

References

Your Turn

  • Have you noticed any of these challenges? How did you solve them?
  • What other problems would you add to this list? Please comment!

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 5: How To Manage Your Bandwidth

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

Another key component of a quality videoconferencing is proper bandwidth management.

First Assess Your Network

  • How much bandwidth are you currently using?
  • Does it sometimes peak to your maximum?

A videoconference of 384K only uses about 400-500K; however, if your bandwidth is full and maxed out; the other traffic can clobber your videoconference so you have very poor quality. If your traffic EVER spikes to the max during school hours when you might have a videoconference, you need to put a solution in place to guarantee the quality of your videoconference. Here are three options:

VLANS

  • Described as a virtual LAN, a VLAN consists of a group of devices/hosts that communicate as if they were on the same broadcast domain, even if not on the same physical location.
  • Example: Most video networks use VLANs to keep their video traffic separate from their normal data traffic. This helps with quality and bandwidth management.

Router QoS

  • Another method is to set quality of service for videoconferencing on the parts of the network that you can control.
  • In Berrien RESA’s case, the schools get their Internet access through us. So we set QoS on their router and on our router. This guarantees the quality of the videoconference between the school and us. This was more essential in the early days of our videoconferencing when the districts had T1s to us. Now most of them are on fiber.

Packet Shaping

  • Another way to guarantee the traffic for the videoconference is by using packet shaping.
  • In Berrien RESA’s case, this is done by using Packeteer to guarantee up to 6 Meg of traffic from our network out to the world for the IP addresses of our videoconference systems and MCU. This means that if our bandwidth out is maxed out; our videoconferences will still be high quality. So far, even on super busy days of 20-30 VCs, we haven’t used more than that 6 Meg.

References

Your Turn

  • How is the health of your network bandwidth?
  • What methods do you use, prefer or recommend for bandwidth management?

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 4: Making H.323 Video Conferencing Work on a Network

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

There are two main methods for installing videoconference hardware on your network. We prefer the NAT static IP method; but we also realize that’s “old school”. Be that as it may, we’ve noticed a trend across the U.S. that some states with a strong Internet2 influence are more likely to use the static IP method.

Let’s consider in more depth the two methods for installing your videoconference system.

1. Static IP NATed Through Firewall

This method provides a public IP address that can be dialed and so the endpoint can easily place and receive calls.

To setup:

  1. First on the router (or firewall), set up a NAT (Network Address Translation) mapping an assigned static public IP address to the internal address that the endpoint will use.
  2. Then, on the endpoint, go into the LAN settings and put in the internal IP address information (DNS, internal IP, gateway, etc.). This part is very similar to how you would set up a computer on your network.
  3. Next, on the endpoint, go into the IP Network H.323 Firewall settings, and add the Public IP address. Some systems have options for autodetecting the NAT, manual defining the NAT, and H.460 Firewall Traversal, and fixed ports. You may need to experiment with these settings until you find the one that works best with your firewall. Change one setting at a time, then try to dial out to a test site and see if it will connect. (At this point, you may or may not receive video from the test site; but at least see if it will dial out.)

The endpoint needs to know the NAT information so that it can properly package the bits of data so that return traffic actually gets through!

Videoconference Traffic Ports
The final area you’ll need to set is to make sure that the firewall is allowing traffic through the right ports for videoconferencing.

First, a little history. The H.323 standard was developed without firewalls in mind. So since then, manufacturers have been challenged to develop equipment and work together to adapt the standards to work better through firewalls. This means that the way H.323 communicates on your network isn’t exactly firewall friendly. It’s helpful to know what happens when a call is set up:

  • First the two systems communicate through TCP and UDP port 1720 to set up the call. This is standard across all vendors.
  • If a gatekeeper is used, then the endpoint communicates with the gatekeeper through ports 1718 and 1719 (TCP and UDP). (More on gatekeepers in a future post.)
  • During this initial communication, the two endpoints talk to each other to share capabilities (called the caps exchange). This includes, which ports the video and audio streaming is shared through. There is a wide range of ports allowed for this streaming, and it depends on your settings (i.e. fixed ports), and the other endpoints settings, on what it will actually settle on.
  • For a full list of ports used in videoconferencing, see this list.

Bottom Line
For ports, you need to open these ports for the static IP that the videoconference system is using:

  • 1720 TCP UDP both ways
  • If you use a gatekeeper off your network, 1718 and 1719. (Janine’s schools do this; Shane & Roxanne’s don’t).
  • The fixed ports you set on the endpoint.

That’s the minimum.

In our cases, we also need to remote manage the school’s endpoints. So we also have the tech director open these ports:

  • Web access (port 80)
  • Telnet access
  • FTP access (for remotely upgrading the system)
  • SNMP (if we have the systems in a management system such as RENOVO, Tandberg Management Suite (TMS), or Polycom Converged Management Application (CMA).

If there are concerns about security, these ports can be set to accept traffic only from our network.

Some Final Notes

  • Call a test site and make sure you can send and receive video and audio.
  • Some of our schools are set up this way, but due to restrictions on the firewall’s capabilities or on the school network policy, the units can only dial out. However, wherever possible, we try to get the units set up so they can place & receive calls to an IP address.
  • One security method is to keep the unit turned off when it is not in use.
  • In some cases, if you do not have the videoconference unit NATed, you are still able to dial out of your network to other public sites, but are not able to have other sites dial back to you.

2. Firewall Traversal Appliance

Firewall

The newer method, recommended by resellers and manufacturers, is to purchase an additional firewall traversal product. The firewall traversal box sits on the edge of the network, usually beside the firewall. In this setup, video traffic goes through the traversal box, and regular traffic goes through the firewall.

Some choices for this product include:

Generally you’ll have better luck if you buy the same vendor’s firewall traversal product as the endpoints.

Installation will be done by the reseller that sold you the equipment; so there isn’t any extra configuration needed on your end.

Dialing
So the way dialing happens with this scenario, is the person off your network calls the IP of the firewall traversal product and the extension of the endpoint. There is no public IP for the endpoint (although if someone wants your public IP, you give them the IP of the firewall traversal product plus the alias or extension.)

The challenge with dialing is that there are currently three different methods for passing the extension, and not all of the vendors support all of the methods. i.e. This is an area that isn’t really standardized yet. It’s a good place for arguments too, as you’ll hear the vendors say their way is better. But as an end user, you need to be able to call any K12 school. Period.

Advantages

  • You don’t have to configure your network as described above.

Disadvantages

  • You will guaranteed have problems with other schools calling you. Cisco-Tandberg units can’t dial into the Polycom method; (although Polycom units can dial the Cisco-Tandberg method). More on dialing in a future post.
  • Extra cost.

References

Your Turn

  • Which method was used for installing your videoconference system?
  • Do you have an opinion or preference for one of these methods? Please share!
  • If you disagree with our view here, we welcome your thoughtful (not flaming) comments.

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.

Day 3: How to Determine Public vs. Private IP Addresses

This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.

Why Do IP Addresses Matter?

IP Addresses are used in standards-based H.323 videoconferencing; not for Skype or other proprietary desktop / web based conferencing tools.

Many corporations only videoconference within their network and therefore don’t need to dial IP addresses. But in the K12 space, we are always dialing out to schools outside of our network / area. So, the way to dial other people is to use their IP address. (Usually. More on other H.323 dialing in a later posts on gatekeepers and firewall traversal units.)

To be able to receive a call from someone, you need to know your public IP address!

Public IP Addresses

A public IP (Internet Protocol) address is an number that is accessible by anyone on the internet. Public IP addresses are reserved for public access. They are used to direct traffic coming in from outside your network. IP address look like this 199.108.230.249 or 12.23.17.16 or some similar variation. Some video conference units enter the dot with a *; and others use a dot. But the number itself has dots! The correct way to refer to it is with the term dot (not period or star or asterisk).

Private IP Addresses

Private IP addresses are used only within your network. No one outside your network can dial a private IP address because they aren’t on your network. Think of it like dialing a phone extension within the school. Outsiders couldn’t get you with just that 3 or 4 digit number. They have to dial the full public number. In this case, they can look similar; the difference is what the number starts with. Private IP addresses always start with:

  • 10.x.x.x
  • 172.16.x.x
  • 192.168.x.x

Dynamic or Static?

You also need to know if your IP is dynamic or static. Dynamic IP addresses change. They can change when a computer (or videoconference system) is rebooted, or when something changes on the network. Static IP addresses are always the same number. Many videoconference systems are installed with a static IP address, as this makes it much easier for others to dial you.

What do you know about your IP address?

  • Does it always stay the same? or does it change?
  • If it changes, do you know how often it changes? What triggers the change? When and how often do you need to check if it changed?

For example, some schools use cable to access the Internet and may not invest in static IP addresses (they usually cost extra with cable). In this case, often when the equipment is turned off and on again, it picks up a new IP address. This behavior is called “dynamic”.

References

Your Turn

  • Do you know your public IP address?
  • Do you know if your address is dynamic or static?

Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.