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CHAPTER 4

Technical Information




This chapter contains the following topics:

SunForum Architecture
T.120 Topology
Using SunForum Through a Network Security Mechanism
Installing and Using TrueType Fonts With SunForum
Calling Into a Multipoint Conferencing Unit
Password-Protected Conferences
Solving Color Problems
SunForum Product Support


SunForum Architecture

The SunForum architecture consists of the International Technical Communications Union (ITCU) protocol standard, T.120, which contains a series of communication and application protocols and services that provide support for real-time, multipoint data communications.

The T.120 architecture is a multilayered design, with defined protocols and service definitions between layers. The upper-level layers require the lower-level layers of the architecture to function.

The lower-level layers (T.122 through T.125) specify an application-independent mechanism for providing multipoint data communication services to any application that can use these facilities.

The upper-level layers define protocols for specific conferencing applications, such as T.127 for multipoint file transfer and T.128 for application sharing.

Applications that use these standardized protocols can coexist in the same conference with applications that use proprietary protocols. In fact, SunForum users can use a mix of standardized and non-standardized protocols.


T.120 Topology

In a conference, a hierarchy exists where the person starting the conference is at the top and those joining the conference are underneath. Where a caller is in this topology affects the conference connection of those who joined that particular caller in the conference. This is illustrated in the following figure.

In this example,

If B hangs up, all those that B called are disconnected as well, leaving A and D in the conference
If D hangs up, only D is disconnected, leaving A, B, and C in the conference
If A hangs up, the entire conference ends

FIGURE  4-1 T.120 Conference Hierarchy

The way you create a conference is to establish one system, the conference host, for conference participants to call in. A star (as in a star networking protocol) topology is created where anyone except the host can leave the conference independently. (This host can actually be a dedicated conference server machine, running a product such as DataBeam neT.120, which can support several conferences simultaneously.)


Using SunForum Through a Network Security Mechanism

If you are connected to the Internet via a network security mechanism, or firewall, (as is usual in most corporate/LAN environments), you can use SunForum to communicate with others located both inside and outside the network security mechanism. To enable full external communication,

Ensure your workstation has its default gateway set to the internal address of the network security mechanism computer.
Configure the network security mechanism to allow primary TCP connections over the following IP ports:
  - 389 (for communication with Internet Locator Servers)
  - 1503 (for T.120 data)

Note - If this is not possible with your network security mechanism, you will not be able to communicate with computers outside the network security mechanism: consult your network security mechanism vendor about upgrading to a version compatible with SunForum.
Configure the network security mechanism to map internal IP addresses to external Internet addresses.

Note - This is not possible with all network security mechanisms. If yours cannot do this, you will be able to call out from inside the network security mechanism, but you will not be able to receive incoming calls from computers outside the network security mechanism.
If you are unsure whether you are connecting to the Internet via a network security mechanism, consult your system administrator or Internet service provider.


Installing and Using TrueType Fonts With SunForum

SunForum is designed to take advantage of a TrueType font server if one is installed on your system (or accessible to your system across a local area network). Solaris 2.6 supports TrueType fonts.

With a TrueType font server installed, SunForum will have more fonts in common with PC systems, resulting in better quality output and improved performance in sharing sessions involving both UNIX and PC systems.


Calling Into a Multipoint Conferencing Unit

SunForum fully supports MCU-hosted conferences, and has been tested with Outreach ConferEase and DataBeam neT.120.

When calling an MCU, specify the address of the MCU as normal. If SunForum detects that the machine called is currently hosting more than one conference, you will be prompted to specify which conference to join. Also, see Password-Protected Conferences.


Password-Protected Conferences

You cannot create a password-protected conference with SunForum.

When you call into a conference that has been designated as password-protected, SunForum will prompt you to specify the password.

Some T.120 implementations incorrectly advertise conferences as password protected, even when no password has been specified. In this case, just click OK without specifying a password; the conference will be established as normal.


Solving Color Problems

If you experience problems with color operations (such as text highlighting) with shared PC applications, try the following:

If your X Server is running with a Static or DirectColor default visual, switch it to run with PseudoColor or GrayScale. See your X Server documentation for information on how to do this.
Close any local color-intensive X applications (such as bitmap editors and web browsers) to make more colors available for SunForum.


SunForum Product Support

If you have any problems installing or using SunForum:

Refer to the written or online documentation included with the software.
Read the rest of the online help, especially the README page, for a list of known problems with this release.
If you are unable to find an answer, contact your Sun representative and have the following information available:
  - Your system configuration (system hardware, operating system version, graphics hardware)
  - A complete description of what you were doing when the problem occurred
  - Any core file generated (check the /opt/SUNWdat directory)
  - The contents of any error log files generated (called TRC1 and/or TRC2 in the /var/opt/SUNWdat/trc directory)



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