Using the Gateway for Data
and Firewall Access Control
Chapter 10 enumerated several arguments for and against using the same branch
office gateway for both voice and data processing. For cost reasons, we’ll presume
that only one gateway is possible no matter what. If we look back to Figure 11.1,
the presumption can easily be made that if Site C had 25 users, then the composite
voice and data demands upon the gateway would be truly awesome. So, a
single router solution to provide that volume of power would be the Cisco 2651,
since this unit is capable of supporting LAN,WAN, and voice I/O cards in one
gateway.While the 175x series gateway can easily handle 25 users, it does not
have the port expandability of the 2600 class gateway. But, to really isolate the
data and voice functions, you could instead purchase a much cheaper Cisco 1601
(R6) to handle the Frame Relay data-only connection, and a separate Cisco 175x
(R7) to handle the external off-net calls plus the voice overhead.The overall cost
of these two gateways is nearly equal to the single 2651, and accomplishes the job
of task separation. Only one extra gateway needs to be added to help manage the
network. Figure 11.7 shows this new configuration.