XtendLan XL-EFM404V, User Manual

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network to a different IP address known within another network. One network is designated the inside network and
the other is the outside. Typically, a company maps its local inside network addresses to one or more global outside IP
addresses and reverse the global IP addresses of incoming packets back into local IP addresses. This ensure security
since each outgoing or incoming request must go through a translation process, that also offers the opportunity to
qualify or authenticate the request or match it to a previous request. NAT also conserves on the nu mber of global IP
addresses that a company needs and lets the company to use a single IP address of its communication in the Internet
world .
3.5. Advance
Note: The advanced functions are only for advanced users to setup advanced functions. The incorrect setting of
advanced function will affect the performance or system error, even disconnection.
3.5.1. STP
STP (Spanning-Tree Protocol) defined in the IEEE 802.1D, is a link management protocol that provides path redundancy
while preventing undesirable loops in the network. For an Ethernet network to function properly, only one active path
can exist between two stations.
Multiple active paths between stations cause loops in the network. If a loop exists in the network topology, the
potential exists for duplication of messages. When loops occur, some switches see stations appear on both sides of the
switch. This condition confuses the forwarding algorithm and allows duplicate frames to be forwarded.
To provide path redundancy, Spanning-Tree Protocol defines a tree that spans all switches in an extended network.
Spanning-Tree Protocol forces certain redundant data paths into a standby (blocked) state. If one network segment in
the Spanning-Tree Protocol becomes unreachable, or if Spanning-Tree Protocol costs change, the spanning-tree
algorithm reconfigures the spanning-tree topology and reestablishes the link by activating the standby path.
Spanning-Tree Protocol operation is transparent to end stations, which are unaware whether they are connected to a
single LAN segment or a switched LAN of multiple segments.