ZyXEL MAX-306 User Guide - Page 132
ALG, Datagram Protocol, or two hours with TCP/IP Transfer Control Protocol/Internet
View all ZyXEL MAX-306 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 132 highlights
Chapter 10 The NAT Configuration Screens 1 Jane requests a file from the Real Audio server (port 7070). 2 Port 7070 is a "trigger" port and causes the WiMAX Device to record Jane's computer IP address. The WiMAX Device associates Jane's computer IP address with the "incoming" port range of 6970-7170. 3 The Real Audio server responds using a port number ranging between 6970-7170. 4 The WiMAX Device forwards the traffic to Jane's computer IP address. 5 Only Jane can connect to the Real Audio server until the connection is closed or times out. The WiMAX Device times out in three minutes with UDP (User Datagram Protocol), or two hours with TCP/IP (Transfer Control Protocol/Internet Protocol). Two points to remember about trigger ports: 1 Trigger events only happen on data that is coming from inside the WiMAX Device and going to the outside. 2 If an application needs a continuous data stream, that port (range) will be tied up so that another computer on the LAN can't trigger it. 10.5 ALG Some applications, such as SIP, cannot operate through NAT (are NAT unfriendly) because they embed IP addresses and port numbers in their packets' data payload. Some NAT routers may include a SIP Application Layer Gateway (ALG). An Application Layer Gateway (ALG) manages a specific protocol (such as SIP, H.323 or FTP) at the application layer. A SIP ALG allows SIP calls to pass through NAT by examining and translating IP addresses embedded in the data stream. 132 User's Guide