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AirCard Smart Cradle
Application Example: Port Triggering for Internet Relay Chat
Some application servers, such as FTP and IRC servers, send replies to multiple port numbers. Using port triggering, you can tell the cradle to open more incoming ports when a particular outgoing port starts a session.
An example is Internet Relay Chat (IRC). Your computer connects to an IRC server at destination port 6667. The IRC server not only responds to your originating source port but also sends an “identify” message to your computer on port 113. Using port triggering, you can tell the cradle, “When you initiate a session with destination port 6667, you must also allow incoming traffic on port 113 to reach the originating computer.” The following sequence shows the effects of this port triggering rule:
1.
You open an IRC client program to start a chat session on your computer.
2.
Your IRC client composes a request message to an IRC server using a destination port number of 6667, the standard port number for an IRC server process. Your computer then sends this request message to your cradle.
3.
Your cradle creates an entry in its internal session table describing this communication session between your computer and the IRC server. Your cradle stores the original information, performs Network Address Translation (NAT) on the source address and port, and sends this request message through the Internet to the IRC server.
4.
Noting your port triggering rule and observing the destination port number of 6667, your cradle creates another session entry to send any incoming port 113 traffic to your computer.
5.
The IRC server sends a return message to your cradle using the NAT-assigned source port
(for example, port 33333) as the destination port and sends an “identify” message to your cradle with destination port 113.
6.
When your cradle receives the incoming message to destination port 33333, it checks its session table to see if a session is active for port number 33333. Finding an active session, the cradle restores the original address information replaced by NAT and sends this reply message to your computer.
7.
When your cradle receives the incoming message to destination port 113, it checks its session table and finds an active session for port 113 associated with your computer. The cradle replaces the message’s destination IP address with your computer’s IP address and forwards the message to your computer.
8.
When you finish your chat session, your cradle eventually senses a period of inactivity in the communications. The cradle then removes the session information from its session table and incoming traffic is no longer accepted on port numbers 33333 or 113.
Control Internet Access
43
5.
Optimize Performance
This chapter contains the following sections:
•
Optimize Internet Gaming with Upstream QoS
•
•
Improve Network Connections with Universal Plug and Play
•
Wi-Fi Multimedia Quality of Service
5
44
AirCard Smart Cradle
Optimize Internet Gaming with Upstream QoS
Upstream Quality of Service (QoS) assigns high priority to Internet traffic from your console gaming system.
Internet
High priority traffic
Best effort traffic
Figure 5. Upstream QoS assigns high priority to gaming traffic from your gaming console
Best practice is for only gamers to enable the Upstream QoS feature. If you do not game and you turn on this feature, some applications might not perform as well as usual.
To enable upstream QoS:
1.
Launch a web browser from a computer or wireless device that is connected to the
Smart Cradle.
2.
In the address field of the browser, enter http://zain.cradle or http://192.168.100.1.
A login prompt displays.
3.
Enter the cradle user name and password.
The user name is admin. The default password is password. The user name and password are case-sensitive.
The BASIC Home screen displays.
4.
Select ADVANCED > Setup > QoS Setup.
Optimize Performance
45
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