How do I avoid Virtual Tributary (VT) Cross-Connect (XC) exhaustion through VT tunneling?
A. When the source VT is at least two hops away from the destination, you can use a VT tunnel to free VT-XC resources in the pass through node(s). In essence, the tunnel keeps the VT 1.5s from being demuxed from the transport Synchronous Transport Signal (STS) at each pass-through node between the source and destination. This tunnel (STS) is reused whenever another VT is created with the source and destination nodes inside the boundaries of an existing tunnel. The tunnel is available to any subsequent VTs until the transport STS is exhausted. Note: Pass-through nodes do not need XC-VT cards. They only need XC cards to perform this function. For an in-depth explanation of how the XC-VT matrix works, refer to Understanding the 15454 XC and XC-VT Switching Matrix.
