Information is starting to be released about carriers participating in the exchanges.Kaiser
The health insurance companies are starting to negotiate with hospitals to get deeper discounts on medical claims. This may be the start of the narrow network.
The narrow network could be a HMO look a like. If you purchase a policy through the Federal Exchange in Indiana, then you could be forced onto a narrow network. You may only be able to use the medical services from one particular hospital. A policy form the exchange plan may not have a traditional PPO feel to it. You will be locked in to only obtaining you medical care from place. This could be fine for routine care but what if you need a transplant?
With the tax credits available through the exchange many people will be forced to except that network because they will not be able to afford a policy outside the exchange. There will be a segment of the population that will not be happy about being restricted to where they receive their medical care. These people will have options to purchase health insurance policies outside the exchange.