Patent Application
20150188821
The present invention relates to data center infrastructure, and more particularly, this invention relates to utilizing a low-latency lossless switch fabric in a data center.
Low latency is a highly desirable feature for data center switch fabric. For example, in high-frequency transactions, low latency allows applications to execute large volumes of orders, such as automated stock trades, etc., at fractions of a second. Similarly, in real-time communications, such as video feeds, telemetry, etc., delays in processing information may be detrimental to user experience or efficient control of devices relying on the video feeds and/or telemetry.
An important problem for low latency switch fabric implementations is that they do not provide deep buffering, and hence packets are lost when the fabric is congested. That is, a switch is not capable of forwarding a packet due to congestion conditions and the switch drops one or more packets, which causes a failure or significant delay of the transaction.
Existing solutions for lossless switches involve internal packet buffering. A buffered switch is configured to send all packets through a memory buffer to avoid packet loss. Unfortunately, this solution causes increases in latency because moving a packet into and then out of memory takes time, thus increasing latency for the solution. Accordingly, a better solution would be beneficial to provide a low-latency lossless switch fabric in a data center.
In one embodiment, a switch includes a processor and logic integrated with and/or executable by the processor, the logic being configured to cause the processor to receive a packet at an ingress port of the switch, forward the packet to a buffered switch when at least one congestion condition is met, where the buffered switch is configured to evaluate congestion conditions of a fabric network, and forward the packet to a low-latency switch when the at least one congestion condition is not met, where the low-latency switch includes an additional policy table provided with forwarding decisions based on the congestion conditions of the fabric network.
In another embodiment, a computer program product for providing low latency packet forwarding with guaranteed delivery includes a computer readable storage medium having computer readable program code embodied therewith. The computer readable program code includes computer readable program code configured to receive a packet at an ingress port of a switch, computer readable program code configured to forward the packet to a buffered switch downstream of the switch when at least one congestion condition is met, where the buffered switch is configured to evaluate congestion conditions of a fabric network, and computer readable program code configured to forward the packet to a low-latency switch downstream of the switch when the at least one congestion condition is not met, where the low-latency switch includes an additional policy table provided with forwarding decisions based on the congestion conditions of the fabric network.
In yet another embodiment, a switch includes a processor and logic integrated with and/or executable by the processor. The logic is configured to cause the processor to receive a packet at an ingress port of the switch, receive congestion information, determine that at least one congestion condition is met based on at least the congestion information, apply a packet forwarding policy to the packet when the at least one congestion condition is met to determine where to forward the packet, determine whether the packet forwarding policy indicates to drop the packet and drop the packet when the packet forwarding policy indicates to drop the packet, forward the packet to a buffered switch downstream of the switch according to the packet forwarding policy when the at least one congestion condition is met, wherein the buffered switch is configured to evaluate congestion conditions of a fabric network, and forward the packet to a low-latency switch according to the packet forwarding policy when the at least one congestion condition is not met, wherein the low-latency switch includes an additional policy table provided with forwarding decisions based on the congestion conditions of the fabric network.
Other aspects and embodiments of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.
The following description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.
Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless otherwise specified.
According to various embodiments described herein, a data center fabric may be configured with a combination of low-latency and buffered switches. The low-latency switches may be provided with switching processors which have additional policy tables provided with forwarding decisions based on congestion of the fabric, which may be provided to the low-latency switches using a feedback mechanism. Depending on congestion conditions in the fabric, a forwarding switch may send packets either to a low-latency or a buffered switch. Further, according to one embodiment, in order to determine which type of switch to forward the packet or to drop the packet, the forwarding switch may apply packet-forwarding policies.
One advantage of this procedure is that the fabric configuration provides the best of both worlds: it has low latency and it enables lossless communications even while the fabric is congested. Another advantage is that the fabric may be easily configured to adapt to a wide variety of data center conditions and data applications.
In one general embodiment, a system includes a switch configured for communicating with a low-latency switch and a buffered switch, the switch having a processor adapted for executing logic, logic adapted for receiving a packet at an ingress port of a switch, logic adapted for receiving congestion information, logic adapted for determining that at least one congestion condition is met based on at least the congestion information, logic adapted for applying a packet forwarding policy to the packet when the at least one congestion condition is met, logic adapted for forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and logic adapted for forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
In another general embodiment, a computer program product for providing low latency packet forwarding with guaranteed delivery includes a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code including computer readable program code configured for receiving a packet at an ingress port of a switch, computer readable program code configured for determining that at least one congestion condition is met, computer readable program code configured for applying a packet forwarding policy to the packet when the at least one congestion condition is met, computer readable program code configured for forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and computer readable program code configured for forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
In yet another general embodiment, a method for providing low latency packet forwarding with guaranteed delivery includes receiving a packet at an ingress port of a switch, determining that at least one congestion condition is met, applying a packet forwarding policy to the packet when the at least one congestion condition is met, forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
According to another general embodiment, a method for providing low latency packet forwarding with guaranteed delivery includes receiving a packet at an ingress port of a switch, receiving congestion information from one or more downstream switches, determining that at least one congestion condition is met based on at least the congestion information, processing the packet to determine at least one property of the packet, applying a packet forwarding policy to the packet when the at least one congestion condition is met, wherein the at least one property of the packet is used to determine if the packet satisfies the packet forwarding policy, forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as “logic,” a “circuit,” “module,” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.
Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a non-transitory computer readable storage medium. A non-transitory computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the non-transitory computer readable storage medium include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), a Blu-ray disc read-only memory (BD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a non-transitory computer readable storage medium may be any tangible medium that is capable of containing, or storing a program or application for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a non-transitory computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device, such as an electrical connection having one or more wires, an optical fibre, etc.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fibre cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on a user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer or server may be connected to the user's computer through any type of network, including a local area network (LAN), storage area network (SAN), and/or a wide area network (WAN), or the connection may be made to an external computer, for example through the Internet using an Internet Service Provider (ISP).
Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatuses (systems), and computer program products according to various embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable medium that may direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
In use, the gateway 101 serves as an entrance point from the remote networks 102 to the proximate network 108. As such, the gateway 101 may function as a router, which is capable of directing a given packet of data that arrives at the gateway 101, and a switch, which furnishes the actual path in and out of the gateway 101 for a given packet.
Further included is at least one data server 114 coupled to the proximate network 108, and which is accessible from the remote networks 102 via the gateway 101. It should be noted that the data server(s) 114 may include any type of computing device/groupware. Coupled to each data server 114 is a plurality of user devices 116. Such user devices 116 may include a desktop computer, laptop computer, handheld computer, printer, and/or any other type of logic-containing device. It should be noted that a user device 111 may also be directly coupled to any of the networks, in some embodiments.
A peripheral 120 or series of peripherals 120, e.g., facsimile machines, printers, scanners, hard disk drives, networked and/or local storage units or systems, etc., may be coupled to one or more of the networks 104, 106, 108. It should be noted that databases and/or additional components may be utilized with, or integrated into, any type of network element coupled to the networks 104, 106, 108. In the context of the present description, a network element may refer to any component of a network.
According to some approaches, methods and systems described herein may be implemented with and/or on virtual systems and/or systems which emulate one or more other systems, such as a UNIX system which emulates an IBM z/OS environment, a UNIX system which virtually hosts a MICROSOFT WINDOWS environment, a MICROSOFT WINDOWS system which emulates an IBM z/OS environment, etc. This virtualization and/or emulation may be enhanced through the use of VMWARE software, in some embodiments.
In more approaches, one or more networks 104, 106, 108, may represent a cluster of systems commonly referred to as a “cloud.” In cloud computing, shared resources, such as processing power, peripherals, software, data, servers, etc., are provided to any system in the cloud in an on-demand relationship, thereby allowing access and distribution of services across many computing systems. Cloud computing typically involves an Internet connection between the systems operating in the cloud, but other techniques of connecting the systems may also be used, as known in the art.
The workstation shown in
The workstation may have resident thereon an operating system such as the MICROSOFT WINDOWS Operating System (OS), a MAC OS, a UNIX OS, etc. It will be appreciated that a preferred embodiment may also be implemented on platforms and operating systems other than those mentioned. A preferred embodiment may be written using JAVA, XML, C, and/or C++ language, or other programming languages, along with an object oriented programming methodology. Object oriented programming (OOP), which has become increasingly used to develop complex applications, may be used.
Now referring to
For physical switch implementations, each physical switch may include a switching processor 320, such as a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a microprocessor, a microcontroller, a central processing unit (CPU), or some other processor known in the art.
For virtual switch implementations, a processor of the server supporting the virtual switch may provide the switching functionality, as known in the art.
Referring again to
According to various embodiments, switch 302 has access to packet forwarding policy 314. In one approach, a physical switch may include the packet forwarding policy. In an alternative approach, a server hosting a virtual switch may comprise the packet forwarding policy. The packet forwarding policy 314 comprises criteria for forwarding packets in congestion conditions along with one or more alternative ports.
For example, the criteria may include packet priority, a destination identifier, e.g., an IP address, a media access control (MAC) address, etc., a traffic flow identifier, e.g., a combination of source and destination addresses, a packet size, a packet latency, virtual local area network (VLAN) tag(s), and/or other related parameters. The alternative port may be a physical port, logical interface, Link Aggregation (LAG) group, virtual port, etc.
In other words, one or more properties of the packet may be determined and used in the packet forwarding policy to determine if the packet satisfies the packet forwarding policy. The property of the packet may include any of the following: a packet priority, a destination application identifier, a source address, a destination address, a packet size, a VLAN identifier, and/or an acceptable latency for the packet.
Now referring to
Each of the steps of the method 400 may be performed by any suitable component of the operating environment. For example, in one embodiment, the method 400 may be partially or entirely performed by a switch in a data center fabric. Particularly, method 400 may be partially or entirely performed by a processor of a switch, with access to packet forwarding policy.
First, as shown in operation 402, a packet of incoming traffic is received (such as at a switch in the data center fabric). In operation 404, it is determined if at least one congestion condition is met. This determination may be made by a processor of a switch, in one embodiment, such as an ASIC, a microcontroller, a FPGA, etc.
In one embodiment, the at least one fabric congestion criteria may include receipt of back pressure from one or more low-latency switches downstream of the switch. In this way, if a low-latency switch is indicating congestion, traffic may be diverted from this switch until it is able to process the traffic it has already been forwarded.
According to various embodiments, the at least one congestion condition may be binary (Yes/No), multi-step, tiered, etc. That is, a multi-step condition may include various levels of congestion criteria in the fabric (e.g., high, medium, low). A tiered condition may include categories, each category including one or more forwarding procedures. For example, different types of packets may be categorized and dealt with differently in the forwarding policy. Depending on the level of congestion, a default action may be adjusted to best handle a run-time situation.
If the at least one congestion condition is not met, the packet is forwarded to a low-latency switch in operation 414. This may be a default action in some approaches as it allows traffic to proceed through the data center fabric in a most expedient manner.
If the at least one congestion condition is met, a packet forwarding policy is applied in operation 406 to determine how to forward the packet. Application of the packet forwarding policy in operation 406 involves determining relevant attributes of the packet. For example, if the policy indicates that lossless treatment is to be provided to packets with a certain priority, priority information is extracted from the packet. All other parameters of the packet, either present in the packet or calculated using an algorithm, may be extracted for future comparison and/or for other comparisons or determinations.
The packet forwarding policy may indicate dropping the packet in one or more scenarios, as shown in operation 408. For example, in one approach, if the packet does not satisfy policy criteria, the packet may be dropped, as shown in operation 412.
If the packet satisfies the packet forwarding policy and it is not dropped, the packet is forwarded to a buffered switch in operation 410. The decision whether to drop the packet or forward the packet to the buffered switch may be made based on a calculated fit between a value extracted in operation 406 and a specification in the packet forwarding policy, according to one embodiment.
Standard flow control protocols which may trigger this mechanism include 802.1Qbb—Priority Based Flow Control (PFC), 802.1az—Enhanced Transmission Selection (ETS), Quantized Congestion Notification (QCN), or any other regular flow control according to IEEE 802.3X.
In more embodiments, referring again to
Each of the steps of the method 500 may be performed by any suitable component of the operating environment. For example, in one embodiment, the method 500 may be partially or entirely performed by a switch in a data center fabric. Particularly, method 500 may be partially or entirely performed by a processor of a switch, with access to packet forwarding policy.
In operation 502, control plane congestion information is received. According to one embodiment, a switch may receive this information relevant to the fabric congestion conditions. The information may be sent from switches connected directly to the receiving switch, from a configuration terminal (or some other central repository of congestion information, such as a server), or some other external agent, as would be understood by one of skill in the art upon reading the present descriptions. According to one embodiment, switching ASICs (from various switches in the data center fabric) may derive the congestion or flow control information from standard flow control protocols and may check their transmit queue level thresholds in order to obtain the control plane congestion information to send to the switch.
In operation 504, the congestion information is processed and in operation 506, it is determined whether at least one fabric congestion criteria is met.
In one embodiment, the at least one fabric congestion criteria may include receipt of back pressure from one or more low-latency switches downstream of the switch. In this way, if a low-latency switch is indicating congestion, traffic may be diverted from this switch until it is able to process the traffic it has already been forwarded.
If the at least one criteria is met, a congestion flag is set in operation 508 and a packet forwarding policy is loaded in operation 512. After the packet forwarding policy is loaded, congestion information is continued to be monitored in operation 514. If the at least one congestion criteria is not met, the congestion flag is removed in operation 510 and congestion information is continued to be monitored in operation 514.
The processing of the congestion information in operation 504 may be implemented in a distributed manner. For example, processing of congestion information may be performed on an external device, a software entity, or some other processing facility capable of processing the congestion information. In this case, the external entity may communicate only the required portions of the congestion information to the switch.
Further, the switch may be configured to modify the congestion criteria or upload policies dynamically, depending on its internal state and available resources.
In more embodiments, referring again to
Now referring to
Each of the steps of the method 600 may be performed by any suitable component of the operating environment. For example, in one embodiment, the method 600 may be partially or entirely performed by a switch in a data center fabric. Particularly, method 600 may be partially or entirely performed by a processor of a switch, with access to packet forwarding policy.
As shown in
In operation 606, the switch determines if the determined egress port is congested. If the egress port is not congested, the packet is forwarded to the egress port for forwarding further along in the fabric.
In one embodiment, it may be determined that the egress port is congested when back pressure is received from one or more low-latency switches downstream of the egress port.
If the egress port is congested, it is further determined if the packet should be dropped in operation 608. In operation 616, the packet is dropped. If it is determined that the packet should not be dropped, in operation 610 the packet forwarding policy is applied. In operation 612, it is determined if the packet satisfies the policy. If not, the packet is dropped in operation 616.
If the packet satisfies the policy, in operation 614, the packet is forwarded to a buffered egress port, in order to account for congestion in the fabric.
In more embodiments, referring again to
For example, in one embodiment, a system may comprise a switch connected to a low-latency switch and a buffered switch. The switch may comprise a processor adapted for executing logic (such as an ASIC), logic adapted for receiving a packet at an ingress port of a switch, logic adapted for receiving congestion information, logic adapted for determining that at least one congestion condition is met based on at least the congestion information, logic adapted for applying a packet forwarding policy to the packet when the at least one congestion condition is met, logic adapted for forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and logic adapted for forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
In another example, a computer program product for providing disjoint multi-paths in a network comprises a computer readable storage medium having computer readable program code embodied therewith. The computer readable program code includes computer readable program code configured for receiving a packet at an ingress port of a switch, computer readable program code configured for determining that at least one congestion condition is met, computer readable program code configured for applying a packet forwarding policy to the packet when the at least one congestion condition is met, computer readable program code configured for forwarding the packet to a buffered switch when the packet satisfies the packet forwarding policy, and computer readable program code configured for forwarding the packet to a low-latency switch when the at least one congestion condition is not met.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of an embodiment of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13741346 | Jan 2013 | US |
| Child | 14656575 | US |
