NetComm NB620W - Manual (Page 72)

NB620W Super-G Wireless Broadband Gateway User Guide YML725 Rev1
72 www.netcomm.com.au
Q: What's MX (Mail Exchanger)? And why MX?
A: The Internet email system for both machines and network connections are prone to error.
With this, a chain of email hubs into the email architecture is built. If the "primary" mail host
goes down, instead of queuing up the mails in the unreliable host on the Internet, they get sent
to the "secondary" or "backup" mail exchanger for delivery, until the primary mail server
becomes functional again. In technical terms, such service is called a Backup Mail Exchanger.
Q: What is PPPoE (PPP Over Ethernet)?
A: PPPoE is known as a dial-up DSL service. It is designed to integrate the broadband services
into the current widely deployed, easy-to-use, and low-cost dial-up-access networking
infrastructure. Thus, customer can get greater access speed without changing the operation
concept.
Q: What is MTU?
A: A maximum transmission unit (MTU) is the largest size packet or frame, specified in octets
(eight-bit bytes), that can be sent in a packet- or frame-based network such as the Internet. The
Internet's Transmission Control Protocol uses the MTU to determine the maximum size of
each packet in any transmission. Too large an MTU size may mean retransmissions if the
packet encounters a router that can't handle that large a packet. Too small an MTU size means
more header overhead and more acknowledgements that have to be sent and handled. Most
computer operating systems provide a default MTU value that is suitable for most users. In
general, Internet users should follow the advice of their Internet service provider (ISP) about
whether to change the default value and what to change it to.
Q: What to do if my USB storage stalls?
A: Please power off your NB620W gateway and then turn it on; the storage device will back to
work. This problem usually caused by unplugging the USB storage device without unloading it
first.