Network FAQ

Do we need an amateur radio ("ham") licence to communicate with the EWN?

No, but you really really ought to at least consult someone who does. SVWUX users are wireless experimenters who are pushing the limits of consumer grade devices past their original design intent in ways that demand much more understanding of electromagnetic theory. Signals in our power class can cause significant interference to industrial, scientific, or medical devices when not handled properly. So for similar reasons why yesterday's radio amateurs were trained and screened before being allowed to operate such equipment, you should consider yourself under similar responsibility to your community. That being said, a large fraction of SVWUX are also licensed hams and/or professional wireless engineers and scientists and we operate with a similar spirit - that of the enjoyment of learning, experimenting and teaching others who are interested. So, lack of knowledge should not disuade you. It should merely motivate you to do some learning first. If you would like to pursue an amateur radio license also, visit the ARRL.

The Part 15 v.s. Part 97 Question?

FCC Part 15 regulations govern low-power unlicensed device usage where Part 97 governs Amateur Radio usage. Part 15 is very limited in power (1 Watt) whereas Part 97 is almost unlimited, relatively speaking (1.5 kilowatt!) In 802.11b/g devices, channels 1 through 6 fall within the Amateur band and can be transitioned to Part 97 power levels by a licensed Amateur Radio operator. Unfortunately, Part 97 power levels bring with them a lot of restrictions on the kind of traffic that can be sent over that radio link such as commercial, governmental or institution sponsored traffic, one way broadcasts, and more. Furthermore, no encryption can be used*. More than annoying, this last item becomes a deal breaker in that no hospital, with current HIPPA data security requirements, will do any serious communications across an unsecured link. This goes for most corporations as well.

Amateur Radio rules also require all links to be under the supervision and control of licensed operators, which quickly becomes problematic when traffic is being passed to and from the internet or civil or NGO sources.

It is true that during an actual emergency these rules are waived but this is not a pragmatic approach. Any gear that we only turn on during a disaster we won't know it's broken until it's too late to fix it. We would prefer to run our network the same way at all times so that we train with the same network we will depend on. So while we may override power constraints during crisis, we must build the system now with that approach reserved as a potential bonus and not as something we will rely on.

Beyond that, it isn't clear that high wattage would be terribly necessary anyway. When links are particularly distant, radios can be configured in point-to-point mode, qualifing them for antenna gain exemptions. These high gain antennas can legally boost the ERP past 60 Watts on 2 GHz or hundreds of Watts on 5 GHz. This is more than enough for our purposes.

* WEP encryption is allowed if the key is publicized, which mostly defeats the purpose, not to mention the fact that WEP is so weak as to be esentially useless even whent the key is secret.

Do we need access to the best repeater sites?

Most large and popular repeater sites are very well located, but they are also very crowded and very noisy. We would prefer more non-traditional sites where noise is not a big problem. We think we will be able to make up for shortcomings in sight-lines so we will take that trade-off.

Will our network be operational only during disasters?

No, it will be operating at all times. If we only operate it during a disaster then we will only find out it's broken during a disaster. Then it's too late to fix it.

We want our network to operate the same way that Amateur Radio repeaters work; they are available for casual use until an emergency, when they are reserved for emergency use.

How will we keep our network from being overloaded?

We will define a number of SSID's (network names) that are available everywhere on our network. Each SSID will be associated with a different VLAN, each with different QoS and Traffic Shaping rules (priorities). For example, First Responders will have all of the bandwidth they need, NGO's will have the next priority, corporations the next, and the general public the last. See Preferential Traffic in the PendingIssues section.

Will this network be for governments only?

No. We feel strongly that disasters effect all of society and therefore all of society should be involved (at some level) in response and recovery. A major part of Silicon Valley's continued success is based on the economic resiliency of it's corporations (not to mention my retirement fund, my kid's college education funds, etc. :-). Therefore we want to provide a mechanism to help this cooperation.

Is everyone allowed to connect to the EWN?

Authentication will require knowing the security key.

Will I be able to reach the EWN from my location?

You will need to be in the line of projection of one of the EWN signals. Then, you will need sufficient antenna gain to travel the distance.

How will EWN connect to the Internet?

We can provide Internet access from any of a number of locations within and from outside Silicon Valley. Any interconnection between the EWN and the wider Internet will be able to provide Internet access to the entire EWN. Our goal is to have a number of interconnect points both inside and outside the Silicon Valley.

How will we provide redundancy and reliability in the EWN?

This is a difficult question. The common, knee-jerk reaction is to have no single-point of failure. But the complexity involved in providing a failover mechanism at every point can often be very fragile, resulting in a net loss of reliability. Our contrasting view leaves every network link as simple as possible but provides redundancy at a higher level, namely at the level of Internet Routing over many connections each utilizing different technologies.

-- Main.Andy - 23 Sep 2008