The Access
Grid is an Internet-based model for video conferencing that focuses on group-to-group
communication, using an ensemble of resources including multimedia large-format
displays, presentation and interactive environments, and interfaces to Grid
middleware and visualization environments.
The Access Grid is used for large-scale distributed meetings,
collaborative work sessions, seminars, lectures, tutorials, and training. Even though the Access Grid is concentrated
on group interactions, it also provides an access point for individual desktop
users, permitting one-to-many or one-to-one communication.
The virtual meeting space, where people come together
to collaborate in the Access Grid, is called a Virtual Venue. If
authorized, the Venue provides users with all the necessary information needed to
communicate with each other, including audio and video streams, user
capabilities, data, services, applications, and connections to other
venues.
Users connect to a Virtual Venue from their
particular environment, identified as a node,
which contains collaborative resources needed to provide high-quality user
experiences. Access Grid users can
configure nodes according to their own preference. Examples of node
configurations are a desktop using a Quick Camera or an entire room with several
microphones, cameras, and advanced display environments. Figure 1 shows one of several nodes available
at Argonne National Laboratory.
Figure 1 A Node at
The Venue Client, in Figure 2, is used to connect to
and participate in an Access Grid Virtual Venue. It displays the contents of the Virtual
Venue, connections to other venues, and an interface to configure your node
arrangement. The description below
explains the different components that represent the Venue Client.
Figure 2 Venue Client
The Address
Bar is used to connect to a venue. You are allowed to enter two different
types of addresses in the address bar, either the default venue on a venue
server (https://host:port/Venues/default) or the actual address of a specific
venue (https://host:port/Venues/unique id).
For instance, you can see in Figure 2 the Venue Client connected to
default venue on a venue server running on host “vv2.mcs.anl.gov” using port
9000. After writing the address in the
address bar, click the “Go” button to connect to the venue.
The Title Bar
gives the name of the venue you are currently connected to.
The Contents
Panel displays participants in
the venue, present data, applications, and services available to share. Users can join the venue either as a single participant
or as a node. A node is a group of
people taking part in the venue together in which all of the participants are
sharing the same collaborative capabilities, for example, watching the venue
projected on a white screen with cameras placed strategically around the room.
The Exits
Panel shows other venues linked
to this venue, connected through exits, enabling users to travel through the
venue space. Next to the door icon you
can see the name of the connected venue.
The venue description is displayed as a tool tip that shows up if the
mouse is held over the exit.
All venue participants and nodes receive the text
available in the Text Field.
You can write a short message in the Message Field and display the text by
clicking on the “Display” button.
This section describes how to use the Venue
Client. The discussion begins with
basics such as setting up certificates and gradually covers such complex issues
as managing a node.
To connect to a venue, you need a valid Grid identity
certificate (for more information about certificates, see Section 3.1). You have to request and configure your
certificate only once; the same certificate can then be used for all future
Access Grid interactions. Also, you
are allowed to use the same certificate on several machines; hence, if you
already have a certificate, you can simply export your certificate files to the
other machines.
Figure 3 Certificate Request Wizard; Step 1
Figure 4 Certificate Request Wizard; Step 2
Figure 5 Certificate Request Wizard; Step 3
If this is the first time you are using the Venue
Client, a profile dialog will appear, and you should enter your information,
which will be used to represent you in venues (see Figure 6). You are required to fill in at least your
name, but it is helpful if you enter as much information as possible. Keep in mind that you can change the profile
at any time (see “Changing Your Profile,” Section 2.4). When you are present in a venue, your profile
information will be made available for every participant in that venue (read
“Viewing Profile,” Section 2.3)
Figure 6 Profile Dialog
Note:
Location: Your physical location, for instance, Argonne
National Laboratory.
Support Information: Information on how to contact the
responsible person for this node, for example, support@mcs.anl.gov.
Home Venue: The address that will show up in the Address Bar when you start the
Venue Client.
Profile Type: Either user, a single participant, perhaps connected via laptop, or
node, representing a group of people using the same collaborative environment
Enter the venue address in the Address Bar, and then click Go
to enter the venue. Apart from venue
addresses (https://<host>:<port>/<unique
id>), you can enter the address of the default venue on a venue server
(https://<host>:<port>/Venues/default), as shown in Figure 7.
Figure 7 Using the Address Bar to
Connect to a Venue
To successfully connect to the venue server, you need
a valid Grid proxy certificate (for more information, read Section 3.1). If such a certificate is missing, the dialog
in Figure 8 will enable you to create a proxy.
In the Pass phrase field,
fill in the password you chose when you initially requested your
certificate. You can set details of this
Grid proxy by clicking the Proxy
Details… button. The “Proxy lifetime
(hours)” field indicates how long this proxy certificate will be valid; the
default value is 8 hours, but you may change this number. When the proxy life time expires, you will be
prompted for your password again. After
specifying the validity of the proxy, click Ok.
Figure 8 Creating a Grid Proxy
Right click on the participant or node you want to
see profile information about, and select View
Profile…, as shown in Figure 9.
Figure 9 View Profile
From the menu, choose Preferences - Edit Profile…,
as shown in Figure 10. When the
Profile Dialog appears, edit the appropriate fields, and then click Ok.
Figure 10 Editing a Profile from the
Menu
Enter text in the Message Field, and click Display.
The text will show up in the Text Field
for all participants in the venue; see Figure 11.
Figure 11 Text Chat
To save text that has been
posted in the Text Field, go to the Venue menu and select Save Text. In the dialog, enter the file location where
you want to save the text, and click Ok.
The My Venues
menu option helps you to save and get easy access to venues you are visiting
often. You can set and go to your home
venue, and you can also add a list of venue names that, when clicked on,
connects to associated venue. This
functionality is available to avoid your having to remember and type long
addresses for venues you are visiting frequently, much like the “bookmark”
feature in most Web browsers.
The address to your home venue will always appear in
the Address Bar when you first start
the Venue Client. You can change this
setting by selecting Set as Home Venue
from the My Venues menu; the venue
you are currently connected to will then be your home venue. You can also change your home venue from your
profile; see “Changing Your Profile” in Section 2.4.
To connect
to your home venue, select Go to Home Venue from the My Venues
menu.
First, go to the menu and click on My Venues - Add Current Venue. The dialog in Figure 12 opens with the
current venue’s name filled in automatically.
You can change the name to whatever you want and then click Ok.
The name will be added to the list found under the My Venues menu option. When
you select a name in the list, the Venue Client will try to connect to the
associated venue.
Figure 12 Associate a Venue Address with a Name
Go to My Venues - Edit in the menu bar, and right click the venue you
want to delete. Select Remove Venue and then click Ok.
Go to My
Venues - Edit in the menu bar, and right click the venue you want to
rename. Select Rename, fill in the new name, and then press Ok.
To the left side of the Venue Client is the Exits
Panel, containing a list of names of other venues. If you place the mouse over one of the exits,
the description of the venue shows up as a tool tip. You can see the description of the Test Room
in Figure 13. If you click the left mouse
button on one of the exits, you will leave the venue you are currently
connected to and enter the other venue.
Figure 13 Navigating
The Venue Client allows you to share data among users
of the venue. Files can either belong to
the venue or be user specific. The user
may carry around personal data when walking between venues. Files belonging to a participant or node will
therefore stay in the venue for as long as its owner is present. Venue data, however, always stays in the
venue until deleted. Personal user data is placed under the participant or node
that owns the file, while venue data is found under the “Data” heading in the
Contents Panel. VenueClient.py, in Figure 14, is one example of a personal file
belonging to Ivan’s Office, and hallo.txt is owned by the venue.
Figure 14 Venue and Personal Data as Displayed in the Venue Client
Right click on the Data heading, and choose Add….
Or, from the menu, go to Venue-Add
Data…. A file browse dialog will show up from which you can pick the file
you wish to add to the venue. Then press
the Ok button.
Right click on your profile under the Participant heading, and choose the
option Add Personal Data. A file browse dialog will show up from which
you can pick the file you wish to add to your personal files. Click the Ok button. Observe that
personal data will be shown under your profile and not under the Data heading, illustrated in Figure
14.
Right click on the data item, personal or venue
specific, and choose Delete. A
dialog will ask whether you really want to remove the selected data. Click Ok
to confirm.
Right click on the data item and choose Open….
If the file type is associated with an application, the data will be
opened directly using that program.
Otherwise you will be prompted for a program to associate with and handle
the file.
Right click on the data item, and choose Properties…. A dialog will be opened
showing the file name, the distinguished name of its owner, and file size.
A useful feature in the Access Grid is the ability to
share applications among several participants. The software includes several
applications that get installed along with the toolkit, such as the Shared
Browser for viewing the Web together and the Shared Presentation for PowerPoint
presentations. However, the Access Grid
is not limited to preinstalled applications. Developers may create and plug in
custom applications that can be made available for venue participants.
Installed applications for your Venue Client are
listed under Start Application Session
in the Venue menu; see Figure
15. To start a session, select an
application from the list. Give the
session a name and a short description before adding it to the venue. The newly created session is listed under the
Application Sessions heading in the
Venue Client.
Figure 15 Shared Application Sessions
To join an application session, right click the
correct name under the Application
Sessions heading and select Open,
as shown in Figure 16. The appropriate application will then launch and display
the current session status.
Figure 16 Application Session Menu
To stop an application session, right click the
correct name under the Application
Sessions heading, and select Delete,
as shown in Figure 16. A dialog will
appear to check that you really want to delete the session. Click Ok
to confirm.
Right click on the session you wish to authorize, and
select Manage Roles… A frame will
display the current authorization setting for this application session. The session has a set of Roles that identifies different authorization privileges for groups
of participants. The authorization
privileges are identified as Actions.
When selecting a role from the left panel, you can see which actions are
enabled for that role in the right action panel. When a role is being expanded, participants
that are included in this role are shown. A participant may be added to several
roles and allowed to perform all actions for that set of roles. You may
add/remove roles, add/remove participants to different roles, and add/remove
actions to roles.
If you want to view those
currently participating in an application session, you may right click the
application session and select Open
Application Monitor…. In addition
to participants, the monitor displays events occurring in the session and data
being exchanged among participants, as shown in Figure 17.
Figure 17 Application Monitor
To view session properties, right click on the
application session and choose Properties…. A dialog will be opened showing the name, URL
address, MIME type, and description associated with the selected session.
In addition to sharing
applications, the Access Grid also allows users to share services.
Before adding a service to the venue, you need to
know the address where the service is located and what MIME type to associate
with the service. The MIME type helps
the Venue Client identify what type of service is being added and how to handle
it. When you have gathered this
information, right click on the Service
heading, and click Add…, or from the
main menu choose Venue-Add Service….
In the dialog, enter the name, URL address, MIME type, and description you want
to associate with the service. Then
click Ok. Figure 18 shows an example of how to add a
service that points to a Web site.
Figure 18 Adding a Service Dialog
To open a service, right click on the service you
wish to use, and select Open.
To delete a service, right click on the service you
wish to remove, and select Delete. A dialog will appear to check that you really
want to delete the service. Click Ok to confirm.
2.11.4 Viewing Service Properties
To view service properties, right click on the
service item and choose Properties…. A dialog will be opened showing the name, URL
address, MIME type, and description associated with the selected service.
Every user and service connected to the Access Grid must
have a valid certificate issued by a trusted certificate authority.
Certificates are a form of electronic identification that is superior to the
well-known and widely used password strategy.
This form of authentication aims to reduce the many problems seen with
passwords, such as poorly chosen, forgotten, or insecurely stored passwords, in
order to enable a reliable environment for collaboration. The certificate authority is responsible for
giving you a certificate.
The most common certificate is the Identity Certificate. It is used to
verify that you are who you say you are when connected to the Access Grid. However, if you are going to run a venue
server, or any kind of service, you should use a Service Certificate. This certificate does not require a pass
phrase and allows the server to stay up and running for longer periods of time.
If you want to know which certificates you have
installed, select Preferences - Manage
Certificates – Certificate Manager… from the main menu. The Certificates tab in Figure 19 shows all
your certificates. If you want to see
more details about a certificate, for instance validity, select it from the
list and click the View certificate button
to the right.
Figure 19 Certificate Manager - Certificates
If you have a certificate you want to use with the
Venue Client, you can import it from Preferences
– Manage Certificates – Certificate Manager… menu. In the Certificates
tab in Figure 19, click the Import
button to the right. The file browse dialog that opens will let you specify
location of the certificate file (usercert.pem) and
the certificate key file (userkey.pem).
If you need to use your
certificate on a different machine, you can export it to a file. In the main menu select Preferences – Manage Certificates – Certificate Manager…. Choose a certificate from the Certificates tab in Figure 19, and then
click the Export button. Enter the name of the file you want your
certificate to be saved to, and click Export
Certificate.
From the main menu, select Preferences – Manage Certificates –
Certificate Manager…. Choose a certificate from the Certificates tab in Figure 19, and then click the Delete button. A dialog will confirm that you really want to
remove selected certificate; click Ok.
Your default certificate
will automatically be used when you run the Venue Client, and the pass phrase
entered when creating a proxy must be associated with that certificate. If you want to change a default certificate,
select from the main menu Preferences –
Manage Certificates – Certificate Manager…. Choose a certificate from the Certificates tab in Figure 19, and then
click the Set as default
button. You can determine which
certificate is the default by looking at the Validity field in the header of the certificate list; it should be
marked with a Y. The identity certificate in Figure 19 is the
default certificate for the client.
You are not
actually using your certificate for authentication. Rather, you have to create a Grid proxy
certificate, which is used for authentication without requiring you to enter
your pass phrase. Once you have
initiated the proxy with your pass phrase, you will not have to enter it again
until the proxy is invalid. However,
longer validity means less security.
To view
proxies currently running, select Preferences
– Manage Certificates – Certificate Manager… from the main menu. The Globus proxies tab in Figure 20 shows a list
of proxies and their information, including the certificate authority that
issued the certificate and how long the proxy is valid. If you want more
details, select a proxy from the list, and click the View proxy button.
Figure 20 Certificate Manager - Proxies
Select Preferences – Manage Certificates –
Certificate Manager… from the main menu. Choose a proxy from the list in
the Globus proxies tab in Figure 20, and click
the Destroy button. A dialog will confirm that you really want to
remove selected proxy; click Ok.
The certificates used by all participants in the
venue are issued by a trusted certificate authority. To find out which certificates are accepted
by your Venue Client, select from the main menu Preferences - Manage Certificates - Certificate Manager…. The Trusted CA Certificates tab lists
acknowledged certificate authorities and their validity. To view more details about
a certificate authority, select it from the list, and click the View certificate button.
A node consists of a node service, one or more
service managers, and one or more services.
One example of a node configuration, pictured in Figure 21, uses three
machines: one for video creation, one for video display, and one for audio. The services, in this case, are used to
produce and receive audio and video.
Each machine runs a service manager communicating with services on that
specific machine. The service managers
are controlled by the node service, which can run on any machine. Default services used by the Venue Client are
VIC for video and RAT for audio.
Figure 21 Example of an Access Grid node layout
If you want to start a
service manager, run AGServiceManager.py.
If you want to start a node service, run AGNodeService.py.
The Venue Client allows you to set up and configure
the resources available in your node layout.
Go to the main menu and click on My Node-Manage…;
the Node Management Window will open. To
the left side of the window you can see a list of Service Managers. A Service Manager is responsible for managing
different services present in your specific node. In Figure 22, the Service Manager is running
on zuz-10.mcs.anl.gov using port 12000.
To the right side of the Node Management window, you can see a list of
services corresponding to the selected item in the Service Manager list. The selected Service Manager is controlling
one audio service responsible for sending and receiving voice communication.
Figure 22 Node Management
If you want to add a new Service Manager, go to the
main menu and select ServiceManager -
Add…, or right click on the Service Manager and select Add…. Enter the computer on
which the service manager is running and the port it is using. When you are finished, click Ok.
If the Service Manager is located on your local computer, it is
sufficient to enter localhost as Hostname;
see Figure 23.
Figure 23 Adding a Service Manager
Select the Service Manager you want to remove, and
then click ServiceManager - Remove in the main menu, or right click
the Service Manager and select Remove.
The Service Manager should disappear from the list.
Select the Service Manager you wish to add a service
to then select from the menu Service-Add…
or right click on a Service Manager and click Add…. A window containing a
list of all available services will be displayed. Select the service to add; then click Ok.
In Figure 24 you can see three existing services to use for voice and
video communication available for Service Manager zuz-10.mcs.anl.gov:12000.
Figure 24 Adding a Service
Select from the list of services the service you wish
to start or stop. Go to the main menu
and select Services – Enable or Services-Disable, or right click on the
service and select Enable or Disable. You should now see the status field for the
service you selected change accordingly in the list.
Select the service you wish to delete from the list of
services and choose from the main menu Service
– Remove, or right click the service and select Remove.
Select the service you want to change, and choose
from the main menu Service - Configure….
You can connect to a node
service running on any machine by selecting from the main menu File-Attach
to Node. Give the host and port
information where the node service is running.
An existing Service Manager configuration can be
loaded with all services added automatically.
From the main menu select File-Load
Configuration…, and select the desired configuration from the list of
names. Then click Ok.
If you know you will use your Service Manager
configuration several times, it is a good idea to store the configuration. You can then simply load the configuration
when you want to use it, instead of adding the same services all over
again. In the main menu, go to File-Save Configuration…, specify the
name you want the configuration to be associated with, and then click Ok.
If you are having problems with multicast on your
network, you can use unicast until the problem is
fixed. This will allow you to run the
media tools even though you are not multicast enabled. From the Preferences
Menu, in the Venue Client, select Use
Unicast.
Please note that not all venues are connected to a bridge server and
will therefore not be able to provide the unicast
option.
The Venue Client provides a
way to quickly turn your video on and off. Go to the Preferences menu
and select Enable/Disable Video. If video is turned off, you will not
send or receive any video.
The Venue Client provides a
way to quickly turn your audio on and off. Go to the Preferences menu
and select Enable/Disable Audio. If audio is turned off, you can not
send or receive any audio.
Access Grid venues has a
role-based security to establish an authorization policy, determining which
participants to let in and with what authority.
Administrators can decide who are allowed to perform different actions,
such as entering the venue or adding data.
To open the authorization frame, go to the Venue menu and select Manage Roles…. The frame in Figure 25
displays current authorization setting for the venue. The venue has a set of Roles that identifies different authorization privileges for groups
of participants. The authorization
privileges are identified as Actions.
When selecting a role from the left panel, you can see which actions are
enabled for that role in the right action panel. When a role is being expanded, participants
included in the role are shown. A participant may be added to several roles and
are allowed to perform all actions for that set of roles. You may add/remove
roles, add/remove participants to different roles, and add/remove actions to
roles.
Figure 25 Authorization
In order to improve the quality of the Access Grid
software, users are encouraged to submit bug reports when experiencing
problems. Also, feature requests and improvements are very welcome and can be
submitted in the same fashion.
Ideally, bug reports are entered manually at the Bugzilla Web site (http://bugzilla.mcs.anl.gov/).
To do so, you need to set up an account with a valid email address. The Access Grid
development team will then process the bug at their earliest convenience, and
comments will get sent to the reporter.
This is the recommended way to file bug reports because they get
organized into categories and reporters will receive and may submit feedback
regarding the bug.
If you do not have time to register with Bugzilla, you can file automatic bug reports using the
Venue Client. In the Help menu
select Submit Error Report of Feature
Request. Though not necessary, you may enter an email address where we can
reach you if you are interested in providing more information regarding the
problem. The bugs will be submitted to the Bugzilla
system; however, the reporter will not receive updates, entered in Bugzilla, about the bug.
Every user and service in the Access Grid must have a
valid identity certificate issued by a trusted certificate authority.
Certificates are a form of electronic identification that is superior to the
well-known and widely used password strategy.
This form of authentication aims to reduce the many problems seen with
passwords, such as poorly chosen, forgotten, or insecurely stored passwords, in
order to enable a reliable environment for collaboration. The certificate authority is responsible for
giving you a certificate; thus, make sure you really are who you say you are.
A certificate is basically used to assure your
security when connected to the Access Grid.
The following are examples of security provided in the certificate
mechanism:
1. Deal with authentication during log in procedures
to identify who you are.
2. Authorize what resources people are allowed and
have permission to access.
3. Preserve confidentiality by just showing given
individuals’ resources and information they are supposed to see, secure
transactions, and so forth.
4. Take care of users’ integrity; for example, back
up resources when something unexpected happens.
For more information about security through
certificates, read http://www.globus.org/security/.
A distinguished name (DN) is a globally unique
identifier that represents the user as an individual. In the Access Grid, DNs
are constructed from entity name and domain information. The following is an
example of a distinguished name "/O=Grid/O=Globus/OU=mcs.anl.gov/CN=John
Doe.”
You are not actually using your certificate for authentication. Rather you have to create a Grid proxy certificate, which is used for authentication without requiring you to enter your pass phrase. Once you have initiated the proxy with your password you will not have to enter it again until the proxy is invalid. However, longer validity means less security.