In early June 2001, the University of Georgia obtained Gigabit Ethernet equipment to replace the venerable broadband network and the ailing fiber network based on asynchronous transfer mode (ATM) technology. A plan for configuring the Gigabit equipment was developed in the summer of 2001. The equipment has been installed in all of the sixteen locations where ATM core devices are located.

The benefits of migrating from the existing campus networks to Gigabit Ethernet are many. First, both the broadband and ATM networks have become increasingly unreliable (the former due to failing aged components and occasional cable cuts from construction work and the latter due to flaky equipment purchased from ATM vendors). The ATM network has also, unfortunately, become even more unreliable as buildings have been migrated to it from the broadband network. Second, the Gigabit network is designed to protect devices in one building from the unwanted traffic coming from other buildings, which is not the case with the broadband or ATM networks.

Third, each building will be capable of exchanging up to 1,000 megabits of information per second (Mbps) through the backbone (compared with 10 Mbps on the broadband and 155 Mbps on the ATM network). The Gigabit backbone itself has a 2,000 Mbps capacity, compared with 10 Mbps on the broadband and 622 Mbps on the ATM backbone. Finally, the new Gigabit network will facilitate the deployment of new applications and services such as Web acceleration, video conferencing and high-speed data transfers.

As buildings are migrated from the broadband or ATM network to the new Gigabit network, networking parameters for all three communications languages (or protocols) supported on campus will have to be changed. These communications protocols are IP (used by any device that talks on the global Internet), IPX (traditionally used in communications between Novell NetWare clients and servers), and AppleTalk (spoken among Macintosh computers and networked devices such as printers). The following sections describe the networking parameters that need to be changed for each of the above communications protocols as well as the optimal migration methods to accomplish those changes.

The order in which buildings will be migrated to Gigabit Ethernet will generally be determined by the current connection method (i.e., ATM first and the broadband second) and how prepared the building is to migrate to Gigabit Ethernet (i.e., DHCP-ready and routed buildings first). Every building has at least one domain network liaison (DNL). If there is more than one DNL per building, they will need to elect a "building DNL" to represent them. The building DNL will send a note to the UCNS Help Desk (helpdesk@uga.edu) when the building is ready to migrate to Gigabit Ethernet. UCNS Telecommunications will contact the building DNL with a proposed migration date. The building DNL will then negotiate an acceptable date between Telecommunications and other DNLs for that building. All migrations will occur during the 5:00 a.m. to 8:00 a.m. time period, unless all parties have agreed to an alternative time.

Every device that communicates on the global Internet must have a (typically unique) network parameter called an IP address. On the Athens campus of the University of Georgia these IP addresses are of the form 128.192.xxx.yyy, where xxx is referred to as the subnet number and yyy is called the host number. Each building on campus is minimally assign one subnet number (with additional subnet numbers assigned if the number of host numbers in use exceeds 250).

Internet devices also need at least two other network parameters to function properly, namely a netmask and a default gateway. Most devices connected to the broadband and ATM networks are configured with a netmask of 255.255.0.0 and a default gateway of 128.192.1.1. When a building is migrated to the Gigabit network, both the netmask and default gateway parameters will have to be changed to 255.255.255.0 and 128.192.xxx.1, where xxx corresponds to the third number in the device's IP address (i.e., the subnet number). One cannot change these parameters prior to Gigabit migration. (Note: In an effort to more efficiently use our IP space, buildings with small numbers of network devices may be assigned a partial subnet, in which case a different netmask and gateway will be required. Departments or buildings behind their own routers may also need special treatment, but the migration to Gigabit Ethernet should be straightforward.)

There are two ways to change these parameters when a building is cut over to Gigabit Ethernet. If the old network parameters are stored permanently in the device, it will cease to communicate with the Internet after the Gigabit cutover, and one will have to visit each device to change the parameters and restore communications. This will likely be necessary for servers and communications hubs, but can be extremely time consuming for most Internet devices such as personal workstations.

A far superior approach for most Internet devices (and one that will minimize downtime when cutover occurs) is to configure them ahead of time to use the Dynamic Host Configuration Protocol (DHCP). DHCP is an excellent technique for managing changes in the network parameters of Internet connected devices such as IP address, network mask, default gateway, etc. DHCP uses a server containing a database of parameters that key off the network interface card (NIC) address of the connected device. A DHCP client program running on the device requests these parameters which are delivered by the DHCP server based on the requesting device's NIC address.

If devices are already configured to use DHCP, then only changes to the netmask and default gateway parameters on the DHCP server are necessary. The devices will have to be rebooted after the cutover, however, to obtain the new parameters. If they are not configured to use DHCP, departments are encouraged to migrate their devices to the central DHCP service developed by UCNS. The document titled Central DHCP Migration Procedures describes the process of converting devices to use this service. As with any DHCP configured device, they will need to be rebooted after the building has been cut over to Gigabit Ethernet to get the new parameters.

Workstations that access file and print resources on NetWare 3.x, 4.x and possibly 5.x servers communicate with them via the IPX communications protocol. The key networking parameter called the IPX network number is given to NetWare client workstations by NetWare servers or communications routers when they boot up. On the broadband and ATM networks, IPX devices (servers, clients and routers) share the same IPX network number across one or more buildings.

When a building is converted to Gigabit Ethernet, it will have its own (new) IPX network number. To convert IPX devices to the new number, which can only be done at Gigabit cutover time, all NetWare servers and communications routers must be manually configured to use that new network number. The document titled Gigabit IPX Network Numbers by Building (**NOT AVAILABLE YET**) provides a list of the numbers which these devices must be reconfigured to use. NetWare client workstations, IPX networked laser printers, etc. then need to be rebooted after migration to Gigabit Ethernet in order for them to obtain the new IPX network number. (Note: Networked laser printers may need to be rebooted a second time to obtain the correct IPX network parameters.)

AppleTalk devices (Macintosh workstations & servers, printers and AppleTalk routers) are assigned addresses consisting of a network address (which is provided by an AppleTalk router as a number within an "AppleTalk cable range") and a dynamic node address determined by the device itself. On the broadband and ATM networks, AppleTalk devices share the same AppleTalk cable range across one or more buildings.

When a building is converted to Gigabit Ethernet, it will have its own (new) AppleTalk cable range. All AppleTalk routers on campus (NetWare servers, Linux servers running NetAtalk, Shiva Net Modems, Cayman Gatorboxes, etc.) need to be set up as "non-seed" routers prior to the cutover so they can obtain their new AppleTalk cable range (as well as AppleTalk zone lists) from the Gigabit router serving their building. All AppleTalk devices (including non-seed routers) then need to be rebooted after migration to Gigabit Ethernet in order for them to obtain the new AppleTalk cable range (and for non-seed AppleTalk routers to obtain the authoritative list of AppleTalk zone names as well).