Dynamical bandwidth adjustment of a link in a data network

1. An apparatus comprising:

a first node configured to receive a plurality of data packets from a plurality of source nodes of a data network and to selectively route a first portion of the received data packets to a link via a port of the first node; and

a link-input buffer being located in the first node and being configured to store the first portion of the received data packets for transmission to the link via the port; and

wherein the first node is configured to power off hardware for transmitting received data packets to the link in response to a fill level of the link-input buffer being below a threshold;

wherein the first node is configured to selectively transmit a second portion of the data packets received therein to a second link connected to another port of the first node;

wherein a second link-input buffer is located in the first node and being configured to store the second portion of the data packets received by the first node for transmission to the second link; and

wherein the first node is configured to power off hardware for transmitting data packets to the second link in response to a fill level of the second link-input buffer being below a third threshold.

2. The apparatus of claim 1 , wherein the first node is configured to drop one or more data packets from the link-input buffer in response to a fill level of the link-input buffer being above a second threshold, the second threshold being less than an available bandwidth of the link.

3. The apparatus of claim 2 , wherein the first node is configured to drop one or more data packets from the link-input buffer with a probability that is monotonic non-decreasing with the fill level of the link-input buffer.

4. The apparatus of claim 1 , wherein the first node is configured to support transport layer operations according to Transmission Control Protocol and to operate the link-input buffer according to a RED protocol.

5. The apparatus of claim 1 , wherein the first node is configured to support transport layer operations according to Transmission Control Protocol and is configured to flow control the link based on queuing delay feedback.

6. The apparatus of claim 1 , further comprising the link, the link being a bundle of parallel physical links, each physical link having an input end-connected to a port of the first node.

7. The apparatus of claim 6 , further comprising a second node having a port connected to the link and being configured to selectively route data packets received from the link to a plurality of destination nodes of the data network and to selectively route some of the data packets received from the link to another link connected to a port of the second node; and

a third link-input buffer being located in the second node and being configured to store some data packets received by the second node for transmission to the second link; and

wherein the second node is configured to power off hardware for transmitting data packets to the second link in response to a fill level of the third link-input buffer being below a threshold.

8. A method, comprising:

receiving a plurality of data packets, by a first node, from a plurality of source nodes of a data network;

selectively routing a first portion of the received data packets to a link via a port of the first node;

storing the first portion of the received data packets in a link-input buffer being located in the first node;

powering off hardware for transmitting received data packets to the link in response to a fill level of the link-input buffer being below a threshold;

selectively transmitting a second portion of the data packets received to a second link connected to another port of the first node;

storing the second portion of the received data packets in a second link-input buffer being located in the first node; and

powering off second hardware for transmitting received data packets to the second link in response to a fill level of the second link-input buffer being below a threshold.

9. The method of claim 8 , wherein the hardware includes hardware for transmitting data from a routing node of the data network to the link, the routing node including the link-input buffer therein.

10. The method of claim 8 , wherein the hardware includes one or more physical links of a link bundle forming the link of a data network.

11. The method of claim 8 , further comprising:

dropping one or more data packets from the link-input buffer in response to determining that the link-input buffer is filled to more than a second threshold, the second threshold being less than an available bandwidth of the link.

12. The method of claim 9 , further comprising operating a portion of the data network including the routing node according to a TCP protocol and an RED protocol.