This is the bit error rate (BER) between the WAC

Routers.  It is equivalent to the packet loss rate of

5×10-4 for the packet length of 64 byte and 1×10-2

for 1518 byte.

 Performance and Functions

 Frame filters function

By using Frame filters function, the transmission data

is filtered on the WAC Router. This function reduces

the control communication frames to be transmitted,

enabling efficient use of the limited bandwidth of the

WAN.  The specified type of message and time stamps

can be transmitted among specified domains and

stations.

 Time synchronization function

Time synchronization function maintains the time

differences among the Vnet/IP domains within 5

seconds via the WAC Routers.  With an SNTP sever

installed in each Vnet/IP domain shortens this time

differences to less than 5 seconds.

 The Bandwidth Limit Function and Preferential

Forwarding of Control Communication Frames

Function

Bandwidth Limit Function suppresses the Control

Communication Frame data volume to interexchange

among the WAN within the limit of the specified

bandwidth or less.  Data overflow among the WAN

exceeding the contracted bandwidth is prevented.

When the Bandwidth Limit Function is activated, the

Preferential Forwarding of Control communication

Frames Function also becomes activated.  In case

the transmission request to exceed the bandwidth

limit occurs, the control communication frame is

transmitted by giving the priorities based on the below

table.  Even when the WAC Router abandons any data

exceeding the bandwidth limit by its Bandwidth Limit

Function; however, transmission of important control

communication frames can be protected.

 Security function

In addition to the Vnet/IP’s security function, the WAC

Router has the function to destroy packets (such data

as unused protocols and unused port numbers) which

are not used in the WAC Router to reduce vulnerability.