network infrastructure basics homework please see description

You are a well-known expert in the design and security of corporate network infrastructures. As such, Z Corporation, Inc. (ZCorp) has contacted you and is requesting a proposal for a network infrastructure integration design. ZCorp is a global financial institution that intends to add Internet Protocol version 6 (IPv6) to its existing network. The headquarters of ZCorp is in Denver, CO and it also has main offices in Sydney, Australia, Vienna, Austria, Tokyo, Japan, and Rio de Janeiro, Brazil. Local routers are providing network services such as Dynamic Host Configuration Protocol (DHCP), network address translation (NAT), and Domain Name System (DNS). It is using Enhanced Interior Gateway Routing Protocol (EIGRP) as its interior gateway protocol and Exterior Gateway Protocol (EGP) as its exterior gateway protocol. Its wide area network (WAN) involves multiple T3 connections and the use of Asynchronous Transfer Mode (ATM). It is unclear to the ZCorp information technology (IT) staff whether they should replace Internet Protocol version 4 (IPv4) with IPv6 or use both versions of IP (dual-stack operation).