But the OverlayLinkType is defined in this draft as 
     enum { reservedOverlayLink(0), DTLS-UDP-SR(1),
             DTLS-UDP-SR-NO-ICE(3), TLS-TCP-FH-NO-ICE(4),
             (255) } OverlayLinkType;

We might need some text about the enum values maps to the ICE RFCs but I don't think change proposed here is right.