Method and apparatus for Ethernet data compression
A method and apparatus for Ethernet data compression enables the size of Ethernet frames to be reduced. Compression and decompression of Ethernet frames occur by the Ethernet network elements, rather than by user computers or end devices that transmit data on the Ethernet network. A new EtherType value may be used to identify the type of compressed Ethernet frames and optionally the type of mechanism used to compress the payload of Ethernet frames. The new EtherType may be inserted into a newly assembled frame ahead of the original EtherType. Alternatively, the new EtherType may replace the original EtherType and a short subheader may be used to identify the original EtherType. Out-of-band network signaling by the Ethernet control plane may also be used to determine whether frames are to be compressed and decompressed over controlled Ethernet links and tunnels, with or without use of the new EtherType.
1. An Ethernet node, comprising:
at least one processor configured:
to obtain a first Ethernet frame, the first Ethernet frame having a first Ethernet header, a first payload portion and a first frame check sequence; and
to compress the first payload portion separately from any data transmitted in any other Ethernet frame using a compression dictionary determined for the first Ethernet frame to form a compressed payload portion, the compression dictionary being created for and used only for the first Ethernet frame and for no other Ethernet frame; and
to create a second Ethernet frame comprising a second Ethernet header, a second payload portion, and a second frame check sequence, the second payload portion including the compressed payload portion and the compression dictionary, the second Ethernet frame being smaller than the first Ethernet frame; and
at least one communication network interface configured to transmit the second Ethernet frame.
2. The Ethernet node of claim 1 , wherein, when a plurality of successive frames are compressed, a respective compression dictionary is determined for each of the successive compressed frames during compression of each of the successive compressed frames.
3. The Ethernet node of claim 1 , wherein the first Ethernet header comprises a first Ethernet frame length value and the second Ethernet frame comprises a second Ethernet frame length value which is smaller than the first Ethernet frame length value.
4. The Ethernet node of claim 1 , wherein the at least one processor is configured:
to check a length of the compressed payload portion; and
to create the second Ethernet frame only when the compressed payload portion is shorter than the first payload portion.
5. The Ethernet node of claim 1 , wherein the first Ethernet header contains a first EtherType value and the second Ethernet header contains an indication of the first EtherType value.
6. The Ethernet node of claim 5 , wherein the indication of the first EtherType value is the first EtherType value positioned in the second Ethernet frame immediately after a second EtherType value.
7. The Ethernet node of claim 5 , where the indication of the first EtherType value is a sub header containing a bit field uniquely identifying the first EtherType value.
8. The Ethernet node of claim 1 , wherein the first Ethernet header contains a first EtherType value and the second Ethernet header contains a second EtherType value that replaces the first EtherType value.
9. The Ethernet node of claim 1 , wherein the at least one communication network interface and the at least one processor are configured:
to participate in out-of-band signaling with other Ethernet nodes of a communication network to determine whether an Ethernet frame should be compressed; and
to compress the Ethernet frame only when it is determined using the out-of-band signaling that the Ethernet frame should be compressed.
10. The Ethernet node of claim 1 , wherein the at least one processor is configured:
to determine whether a communication network is experiencing congestion; and
to compress the first Ethernet frame only when it is determined that the communication network is experiencing congestion.
11. The Ethernet node of claim 1 , wherein the at least one processor is configured:
to determine whether an Ethernet frame is already compressed; and
to compress the Ethernet frame only when it is determined that the Ethernet frame is not already compressed.
12. The Ethernet node of claim 1 , wherein the at least one processor is configured to obtain the first Ethernet frame by receiving the first Ethernet frame from the at least one communication network interface.
13. The Ethernet node of claim 1 , wherein:
the at least one communication network interface is configured to receive an Ethernet frame; and
the at least one processor is configured:
to determine whether the received Ethernet frame is compressed; and
when the Ethernet frame is compressed, to decompress the frame using a compression dictionary that is included in a payload portion of the received Ethernet frame.
14. The Ethernet node of claim 13 , wherein the at least one processor is configured to determine whether each of a plurality of successive Ethernet frames are compressed and decompress any compressed frames frame-by-frame, decompressing each compressed frame using a respective compression dictionary that is included in a respective payload portion of each compressed frame.
15. The Ethernet node of claim 13 , wherein the at least one processor is configured:
to determine a previous EtherType value from a compressed frame; and
to restore the previous EtherType value when the compressed frame is decompressed.
16. The Ethernet node of claim 15 , wherein the at least one processor is configured to determine the previous EtherType value from a sub header of the compressed frame.
17. The Ethernet node of claim 16 , wherein the sub header contains a bit string uniquely identifying the previous EtherType.
18. The Ethernet node of claim 13 , wherein the at least one communication interface and the at least one processor are configured to participate in Ethernet operation, administration and maintenance (OAM) signaling to collectively specify which Ethernet frames are to be compressed and decompressed.