3Com Nbx 100 And Ss3 Nbx Administration Guide

Checking Connections441
Alternate
GatekeepersA zone can contain only one gatekeeper at a time, although multiple 
distinct devices can provide the gatekeeper function in a zone. Multiple 
devices that provide the RAS signaling function for the gatekeeper are 
called alternate gatekeepers. Each alternate gatekeeper appears to each 
endpoint as a distinct Gatekeeper.
To ensure system availability, redundancy, and scalability, the gatekeeper 
can provide RAS signaling function by using multiple physical or...

442APPENDIX A: CONNEXTIONS H.323 GATEWAY
Local Considerations
All voice packets that move between an NBX Business or Basic Telephone, 
Call Processor, ConneXtions gateway, and router on the LAN have a high 
priority and high quality of service. 
However, at the router and beyond, network administrators can influence 
H.323 call quality through the priority that they give to H.323 packets at 
both the internet router and at the firewall.If H.323 connections 
consistently experience significant delays, you...

Checking Connections443
■(It is normal for a first ping to fail and subsequent pings to 
succeed).
■Subsequent requests timed-out
■(Indicates some packet loss. Rerun using the “-n 100” option. The 
“request timed out” number represents the percentage of lost 
packets. These packets could have been lost in either direction.)
bDestination host not reachable
■Ping couldn’t negotiate a path to the specified address
(PC is not plugged into LAN, incorrect gateway address in route, 
or a firewall blocked the...

444APPENDIX A: CONNEXTIONS H.323 GATEWAY
In addition to the NetMeeting software, participating computers need an 
audio card with a headset (or speakers) and a microphone. The audio 
card must support full-duplex 64 Kbps transfers.
Note that it is possible for a NetMeeting connection to be unsuccessful 
and still have a successful ConneXtions installation. This can occur 
because ConneXtions restricts the range of TCP and UDP ports used but 
NetMeeting allocates its ports from a wider pool. For more...

Checking Connections445
6Install the NetMeeting files and respond to the prompts:
aSelect Open when the download is complete.
bClick Ye s to confirm installation.
cClick Ye s to acknowledge the legal agreement.
dClick OK to accept the default installation directory.
eClick OK to acknowledge successful installation.
7Open NetMeeting:
aClick Next on next two screens.
bEnter your details as required.
cClick Next on next two screens.
dClick Put a Shortcut to NetMeeting on My Desktop.
eClick Next on next two...

446APPENDIX A: CONNEXTIONS H.323 GATEWAY
■Call rings remote end and it answers, but there is no audio.
Faulty connection to a microphone, speaker or both.
Firewall is blocking audio (UDP) packets.
■Calls work in one direction, but not in the reverse direction. Place a 
call to determine which firewall is blocking TCP traffic. Once you 
determine this, it is the remote firewall that is blocking the traffic.
Placing CallsYou can place an outgoing H.323 call from an NBX system in one of 
several ways, as...

Placing Calls447
Extension Lists
You can configure H.323 ports for single-digit access (usually 8) instead of 
a specific 3-digit line extension. The single-digit access allows the NBX 
system to select an available line port when you place an external call.
Internet IP line ports and CO (central office) line ports must never be 
assigned to the same extension list because they use very different dial 
plans. Conventional practice is to use 9 for external switched network 
(PSTN) connections and 8 for...

448APPENDIX A: CONNEXTIONS H.323 GATEWAY
Speed dial numbers can be system-wide or personal. System speed dial 
numbers (700-799) apply system-wide and are programmed by the 
system administrator. Personal speed dial numbers (601 through 699) 
apply only to an individual telephone; they are programmed by its owner.
You can assign any of the first ten speed dial numbers in each type group, 
system or personal, to any Access button on a telephone.
For more information, see Chapter 6 of the NBX Telephone...

Placing Calls449
One Button AccessYou can configure an Access button on a NBX system to dial a complete 
H.323 (or switched) dial sequence. 
This procedure assumes that all buttons available for one-button access 
are configured in the first ten system (or personal) speed dial locations.
To set up one-button dials:
1In the NBX NetSet - Main Menu window, click Device Configuration.
2Click the Telephones tab or the Group Telephones tab. Select a telephone 
extension or a telephone group.
3Click Button...

450APPENDIX A: CONNEXTIONS H.323 GATEWAY
Receiving CallsConneXtions gateways route incoming calls to any available H.323 port. 
The NBX system then connects this port to the extension specified during 
port configuration. H.323 ports are configured through the NBX software 
just like line card ports. Selectable extensions are: 
■Auto Attendant (500)
■Receptionist’s telephone (usually the lowest numbered extension on 
the system, with a default of 1000 on the SuperStack 3 NBX system or 
100 on the NBX 100...