Summer 2007 Wireless Expansion Update
August 1, 2007
Wireless at Georgia Tech continues to see considerable
growth, with peak usage of the wireless LAWN nearly exhausting the address
space range which was allocated last year. We expect a
dramatic increase in the number of devices on the LAWN this Fall as all of
the residence halls will have wireless coverage, as well as the addition of
wifi to numerous mainstream devices like game controllers and cell phones.
We have added a new address space for wireless users: 220.127.116.11/20.
The complete list of LAWN networks will then be as follows:
We will begin using the new address space shortly before the beginning of the fall semester to accommodate the anticipated demand. This address block is not contiguous with the existing wireless block of address; however, we will be working to maintain mobility such that users can continue to roam anywhere on the LAWN without being logged out so long as their dhcp lease is renewed. Currently the lease time is set at 30 minutes, so users have an average of 15 minutes before being logged out when idle. System and network administrators who limit or enable services available to LAWN addresses should add the new range of addresses. Alternately, they could rely on the address to resolve to a DNS name of the form lawn-[IP].lawn.gatech.edu to guard against future changes of this nature should they become necessary. All OIT managed departmental firewalls have been updated with the new address range, using the locally defined policy for the LAWN for each firewall.
On a related note, users should consider disabling their wireless cards whenever they are plugged into a wired network. This will help to reduce the number of IP addresses leased (DHCP) but not in use on the LAWN. Most laptops have a button, switch, or function key sequence which quickly disables or enables the wireless card in addition to methods in the operating system.
In order to support mobility, reduce operational overhead, and increase the resiliency of the wireless network under load and failures we have introduced wireless controllers into the architecture. This process began with the installation of wireless in the Klaus building last fall, and has enjoyed great success. Most users will not see any difference in the user experience between the old and new architecture. In some cases the coverage and capacity of the network under normal conditions will improve given the adaptive features of the controller architecture. Some users who rely on layer 2 broadcast features (iTunes music sharing for example) will be impacted as the controllers suppress broadcast traffic for security and performance reasons. Over the coming weeks we will be migrating existing access points to the controller architecture; however this should be transparent as we will do this at off peak times and when no users are associated with an access point.
Last year OIT conducted a wireless site survey of all outdoor areas on the Atlanta campus. This fall we will begin to implement that survey as our budget allows. We will initially concentrate on upgrading and expanding areas of existing low quality coverage and areas using legacy equipment for coverage. Beyond that we will focus on areas that are not covered but represent high population or high impact areas. If you know of specific outdoor areas that you think we should consider for coverage or coverage improvements, please let us know.
For discussion, issues, or questions regarding this change please use the Connectivity Forum or contact the OIT wireless team: (firstname.lastname@example.org).