aDSL Modems

Sort of a newbie on VOIP, but read on Wikipedia (VOIP topic) that:

“However, a majority of DSL providers use only one virtual (VC) for each customer, even those with bundled VoIP service. Every Ethernet frame must be completely transmitted before another can begin. If a second VC were established, given high priority and reserved for VoIP, then a low priority data packet could be suspended in mid-transmission and a VoIP packet sent right away on the high priority VC. Then the link would pick up the low priority VC where it left off. Because ATM links are multiplexed on a cell-by-cell basis, a high priority packet would have to wait at most 53 byte times to begin transmission. There would be no need to reduce the interface MTU and accept the resulting increase in higher layer protocol overhead, and no need to abort a low priority packet and resend it later.”

Do any aDSL modems offer mulitple VCs, do they really lead to meaningful improvement in VOIP functionality, and, if either or both are true, how do I get one of these modems? ISPs seem to just dump you with whatever they’ve bulk negotiated, modem-wise.

Thanks beforehand,