Method and system for nesting of communications packets
View Patent ↗A serial communications architecture for communicating between hosts and data store devices. The Storage Link architecture is specially adapted to support communications between multiple hosts and storage devices via a switching network, such as a storage area network. The Storage Link architecture specifies various communications techniques that can be combined to reduce the overall cost and increase the overall performance of communications. The Storage Link architecture may provide packet ordering based on packet type, dynamic segmentation of packets, asymmetric packet ordering, packet nesting, variable-sized packet headers, and use of out-of-band symbols to transmit control information as described below in more detail. The Storage Link architecture may also specify encoding techniques to optimize transitions and to ensure DC-balance.
1. A method for transmitting packets, the method comprising:
receiving a first packet;
transmitting a portion of the received first packet;
receiving a second packet;
upon receiving the second packet,
stopping the transmitting of the first packet so that not all of the first packet has been transmitted;
transmitting a preempt indicator;
transmitting the second packet; and
upon completion of transmitting the second packet,
transmitting a continue indicator; and
transmitting the portion of the first packet that has not yet been transmitted;
wherein the packets include in-band symbols and the indicators include one or more out-of-band symbols.
2. The method of claim 1 wherein the transmitted indicators are primitives.
3. The method of claim 1 wherein the in-band symbols are transition optimized and the out-of-band symbols are not transition optimized.
4. The method of claim 1 wherein the first packet is a data packet and the second packet is a control packet.
5. The method of claim 1 wherein the first and second packets are transmitted through the same communications link.
6. The method of claim 1 wherein the transmitting of the second packet is preempted so that a third packet can be transmitted.
7. The method of claim 1 wherein the first packet includes a header that is transmitted only once.
8. A method for receiving packets, the method comprising:
receiving a first portion of symbols of a first packet;
receiving a preempt indicator indicating that a second packet of symbols is to be received;
receiving the second packet of symbols;
receiving a continue indicator indicating that a second portion of symbols of the first packet is to be received; and
receiving the second portion of symbols of the first packet;
wherein the symbols of the packets include in-band symbols and the indicators include one or more out-of-band symbols.
9. The method of claim 8 wherein the received indicators are primitives.
10. The method of claim 8 wherein the in-band symbols are transition optimized and the out-of-band symbols are not transition optimized.
11. The method of claim 8 wherein the first packet is a data packet and the second packet is a control packet.
12. The method of claim 8 wherein the first and second packets are received via the same communications link.
13. The method of claim 8 wherein the receiving of the second packet is preempted so that a third packet can be received.
14. The method of claim 8 wherein the first packet includes a header that is received only once.
15. A method for transmitting packets via a communications link, the method comprising:
transmitting a first portion of a first packet;
transmitting a preempt indicator indicating that a second packet is to be transmitted;
transmitting the second packet;
transmitting a continue indicator indicating that a second portion of the first packet is to be transmitted; and
transmitting the second portion of the first packet
wherein the first and second packets and the preempt and continue indicators are transmitted via the same communications link and wherein further the packets include in-band symbols and the indicators include one or more out-of-band symbols.
16. The method of claim 15 wherein the indicators are primitives.
17. The method of claim 15 wherein the in-band symbols are transition optimized and the out-of-band symbols are not transition optimized.
18. The method of claim 15 wherein the first packet is a data packet and the second packet is a control packet.
19. The method of claim 15 wherein the transmitting of the second packet is preempted so that a third packet can be transmitted.
20. The method of claim 15 wherein the first packet includes a header that is transmitted only once.
21. A communications device for transmitting packets via a communications link, comprising:
a transmission component that transmits a first packet; and
a preemption component that signals the transmission component to stop transmitting the first packet, transmits a preempt indicator indicating that a second packet is to be transmitted, transmits the second packet, and signals the transmission component to continue transmitting the first packet;
wherein packets include in-band symbols and the indicators include one or more out-of-band symbols.
22. The communications device of claim 21 wherein the indicators are primitives.
23. The communications device of claim 21 wherein the in-band symbols are transition optimized and the out-of-band symbols are not transition optimized.
24. The communications device of claim 21 wherein the first packet is a data packet and the second packet is a control packet.
25. The communications device of claim 21 wherein the transmitting of the second packet is preempted so that a third packet can be transmitted.
26. The communications device of claim 21 wherein the first packet includes a header that is transmitted only once.