Tuesday, June 3, 2008

Tier 2 Regional Rotate APRS Servers

News from Tier 2 HQ...


Good morning from Tier 2 headquarters in sunny southern California! I would like to take this time to outline some important changes/enhancements to the APRS Tier 2 server network. The network has been quietly growing again in the past year. We now have 44 servers online in 19 different countries, and 8 more servers are currently under sea trials. A positive benefit to this growth has been the influx of great knowledge from the different sysops that has allowed us to make many enhancements to the network as well.

Most recently, there was a thread on the APRS SIG regarding rotate addresses [again]. Most of us at Tier 2 are still firm believers that if your client software allows you to set one or more server names manually, then you should always do that before utilizing a round-robin rotate address, but we also recognize that there are software packages that do not offer that. There are also folks who will always want the simple answer, and the rotate addresses to offer a simple, if not the most effective, connection option. The down sides of round-robin DNS are well documented, even on these lists, so I wont repeat them. However, we at Tier 2 recognized early on the desire for regional association with operations. Based on some recent threads, this seems
to also be true for rotate addresses. For some time now, rotate.aprs2.net has been available as a connection option to Tier 2. This address keeps a pool of no more than 22 of the Tier 2 servers (to accommodate some router firmware that will not parse more than 22) and automatically adjusts for servers that go offline. It is a fairly effective setup, but some clients have responded that they do not understand why their UI-View program running in Tuscaloosa is connected
to the APRS server in Thailand. While internet routing vs. political boundaries is an interesting study, suffice it to say that most clients will want to connect to something that makes regional sense. So for the past five months, our sysops have been working on and testing a regional rotate address system for Tier 2 that addresses many of these issues.

Based on the packet radio network routing names of several years past, we have broken down the world into five server regions, and have assigned servers to those five addresses in those regions. Again, based on the packet radio routing model, we have created the following five regional rotate addresses:

Information about which server is in which region, along with a map of the five server regions, can be found right on the Tier 2 home page http://www.aprs2.net/ There were two debates that ran for a long time in developing this scheme. First, there are often political questions when assigning various countries of the world to a region - most notably is the question of where Europe and Asia are separated. I can assure you that there was no political or nationalistic malice in choosing where servers were placed! Simple logic was employed. Secondly, it had been requested that we try to adhere to strict internet routing - i.e. have the client connect to the server that was closest in IP terms. Unfortunately, while that make very good technical sense, there really is no way to effectively trace and catalog the routes from each potential client to each of the servers. At any rate, this setup seems to be working well, and so it is time to roll it out. Again, I still believe you should be trying to use actual server addresses whenever possible, but if you are looking for a regional rotate address that makes more sense to you, you now have it!

We always welcome comments and suggestions. We serve the APRS-IS's 30,000 plus clients with an average of 1,850 at any given time. This is your network and we are happy to be the maintenance crew for it. Thanks again, and enjoy!

73, on behalf of the Tier 2 team.
Phil Pacier - AD6NH
Tier 2 Network Coordinator


No comments: