Can there be multiple links between nodes?

Q1:Can there be multiple links between two nodes?Like this :

Q2:I set toMaxLinks and fromMaxLinks equal to 1000, but the link between two nodes can only be connected once.

var gnTemplate =
g_(go.Node, "Auto",   
    { selectionAdorned: true,
      resizable: true,
      //layoutConditions: go.Part.LayoutStandard & ~go.Part.LayoutNodeSized,
      portId: "1",
      fromLinkable: true,
      toLinkable: true
      //fromSpot: go.Spot.AllSides,
      //toSpot: go.Spot.AllSides 
      new go.Binding("angle","angle").makeTwoWay(), 
      new go.Binding("category","category").makeTwoWay(), 
      new go.Binding("location","loc",go.Point.parse).makeTwoWay(go.Point.stringify), 
      new go.Binding("desiredSize","desiredSize",go.Size.parse).makeTwoWay(go.Size.stringify),

      g_(go.Shape, "Rectangle",
      { fill: null, stroke: "#ff0000", strokeWidth: 3 ,minSize: new go.Size(100, 100)}),
          alignment: go.Spot.Center,
          //margin: new go.Margin(0, 14, 0, 2),  
          font: "bold 16px sans-serif"
        new go.Binding("alignment").makeTwoWay(), 
        new go.Binding("font","font"), 
        new go.Binding("stroke","color"), 
        new go.Binding("text","text").makeTwoWay()

Yes. The links that a user can draw are controlled by linking validation properties, as discussed in GoJS Validation -- Northwoods Software.

This covers your case specifically: GoJS Validation -- Northwoods Software