Appeal 2007-1063
Application 09/881,594
sessions between a Messaging Application Programming Interface (MAPI)
client, located behind a firewall and NAT, and a MAPI server (Br. 4:13-15).
Like Appellant’s invention, Thomas teaches a system and method for
communication with a client located behind a firewall and network address
translator (FF 4). Thomas teaches that the client sends an identifying
message to a node on the other side of the firewall / NAT; receiving a
response from the node, wherein the messages from the client and node
cause creation of a path through the firewall / NAT; and conducting repeated
further communication between the client behind the firewall and the node
on the other side of the firewall (FF 6).
Because Thomas teaches communication between a client behind a
firewall and NAT, and a node on the other side of the devices (FF 4),
Thomas necessarily uses similar address translation methods, because of the
presence of the known NAT (see FF 7). Thomas further teaches that this
communication may be repeatedly “initiated” by invoking a function known
as “Firewall Keep-Alive” (FF 10). In the system of Thomas, the user may
select the desired interval between initiation of communication sessions (FF
8). “Initiation” of communication at sufficiently short intervals, i.e. shorter
than the time-out in the NAT after which address translation information is
deleted, results in a device in which communication is “maintained” just as
Appellant argues. Subsequent communication “initiation” from the client
would occur before the address information in the NAT expired (see FF 7),
and thus the communications path through the firewall would never be
dropped. Appellant has presented no evidence that the thirty second interval
between sessions disclosed in Thomas (FF 10) is insufficient to “maintain”
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