Failback to a primary communications adapter
Methods, systems, and program products are provided for failback to a primary communications adapter. Embodiments of the present invention include receiving, in a driver for a primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter; determining that the primary communications adapter is capable of receiving packets; setting the backup communications adapter to idle; and activating the primary communications adapter. In typical embodiments, the primary communications adapter includes a plurality of linked communications adapters comprising an EtherChannel pseudo-adapter.
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1. Field of the Invention
The field of the invention is data processing, or, more specifically, methods, systems, and products for failback to a primary communications adapter.
2. Description of Related Art
EtherChannel is a link aggregation technology that allows several Ethernet adapters to be aggregated together to form a single pseudo-Ethernet adapter having increased bandwidth and fault-tolerance. All the aggregated adapters in the EtherChannel are typically given the same link layer address and are treated by remote systems as a single adapter. One benefit of EtherChannel is that the aggregated adapters have the network bandwidth of all of their adapters in a single network presence. If a single adapter fails, network traffic is automatically sent on the next available adapter in the EtherChannel without disruption to existing user connections.
Although failure of the EtherChannel is less likely than the failure of a single Ethernet adapter, failure of the EtherChannel does occur. To provide failover protection for the EtherChannel, typically a backup Ethernet adapter remains idle until all the primary adapters in the EtherChannel fail. When the primary adapters in the EtherChannel fail, the backup adapter is activated and administers all Ethernet traffic until at least one of the primary adapters recovers. When at least one of the primary adapters recovers, the primary channel is again available for all traffic and the backup adapter is reset to its idle state.
It is desirable to return Ethernet traffic across the primary EtherChannel as soon as the primary EtherChannel recovers, because the EtherChannel has more bandwidth than the backup adapter. Conventional EtherChannel drivers provide automatic failover to a backup adapter and dynamic reconfiguration of the primary EtherChannel. Dynamic reconfiguration of the primary EthernetChannel typically includes re-establishing electrical connectivity in the physical layer Ethernet adapter and initializing the ports connecting LAN segments in the link layer. When electrical connectivity to the adapter is established the adapter sends a ‘link up event’ to the EtherChannel driver. Although there is electrical connectivity to the physical layer Ethernet adapter, the Ethernet adapter is not capable of sending packets until a dynamic reconfiguration process initializes the ports connecting segments in the LAN, thereby allowing packets received through the adapter to be forwarded in the LAN. Failback to the primary EtherChannel before the primary adapters are capable of sending packets results in lost packet traffic. There is therefore a need for improved failback to a primary communications adapter.
SUMMARY OF THE INVENTIONMethods, systems, and program products are provided for failback to a primary communications adapter. Embodiments of the present invention include receiving, in a driver for a primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter; determining that the primary communications adapter is capable of receiving packets; setting the backup communications adapter to idle; and activating the primary communications adapter. In typical embodiments, the primary communications adapter includes a plurality of linked communications adapters comprising an EtherChannel pseudo-adapter.
In many embodiments, determining that the primary communications adapter is capable of receiving packets is carried out by sending a packet from the backup communications adapter to the primary communications adapter and receiving the packet in the primary communications adapter. In some embodiments, sending a packet from the backup communications adapter to the primary communications adapter includes broadcasting an ARP packet to all link layer addresses on a LAN. In some embodiments, determining that the primary communications adapter is capable of receiving packets is carried out by predetermining a period of time to initialize the ports connecting segments of a LAN.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described to a large extent in this specification in terms of methods for failback to a primary communications adapter. Persons skilled in the art, however, will recognize that any computer system that includes suitable programming means for operating in accordance with the disclosed methods also falls well within the scope of the present invention. Suitable programming means include any means for directing a computer system to execute the steps of the method of the invention, including for example, systems comprised of processing units and arithmetic-logic circuits coupled to computer memory, which systems have the capability of storing in computer memory, which computer memory includes electronic circuits configured to store data and program instructions, programmed steps of the method of the invention for execution by a processing unit.
The invention also may be embodied in a computer program product, such as a diskette or other recording medium, for use with any suitable data processing system. Embodiments of a computer program product may be implemented by use of any recording medium for machine-readable information, including magnetic media, optical media, or other suitable media. Persons skilled in the art will immediately recognize that any computer system having suitable programming means will be capable of executing the steps of the method of the invention as embodied in a program product. Persons skilled in the art will recognize immediately that, although most of the exemplary embodiments described in this specification are oriented to software installed and executing on computer hardware, nevertheless, alternative embodiments implemented as firmware or as hardware are well within the scope of the present invention.
Failback to a Primarily Communications Adapter Exemplary methods, systems, and products for failback to a primary communications adapter are now explained with reference to the accompanying drawings, beginning with
In the example of
Each device in the example of
The communications adapters installed in the devices of
Each device in the example of
The arrangement of servers and other devices making up the architecture illustrated in
For further explanation,
Because each link layer address is unique to a device on a LAN, the link layer protocol (206) operates generally by circulating all messages packets on a LAN to each device connected to the LAN. Each packet includes a destination link layer address. Each device is then responsible for examining each packet, and discarding those not addressed to the device, and passing those that are addressed to the device up the protocol stack for further handling.
The stack of
Data communications (212) in such a stack model is viewed as occurring layer by layer between devices, in this example, between devices (102, 104). That is, data communication between the devices in the physical layer is viewed as occurring only in the physical layer, communication in the link layer is viewed as occurring horizontally between the devices only in the link layer, and so on.
Vertical communication through among the protocols in the stack is viewed as occurring through application programming interfaces (“APIs”) (210) provided for that purpose. A browser, for example, operating as an application program in the application layer views its communications as coming and going directly to and from its counterpart web server on another device across the network. The browser effects its data communication by calls to a sockets API that in turn operates a transmission control protocol (“TCP”) client in the transport layer. The TCP client breaks a message into packets, gives each packet a transport layer header that includes a sequence number, and sends each packet to its counterpart on another device through an API call to the network layer. The network layer may implement, for example, the well known Internet Protocol (“IP”) which give each packet an IP header and selects a communication route through the network for each packet, and transmits each packet to its counterpart on another device by calling down through its link layer API, typically implemented as a driver API for a data communication adapter such as a network interface card or “NIC.” When receiving data communication, the process is reversed. Each layer strips off its header and passes a received packet up through the protocol stack. Upward passes above the link layer typically require operating system context switches.
As mentioned above, devices capable of failback to a primary communications adapter according to embodiments of the present invention are generally implemented as automated computing machinery. For further explanation,
The example computer (134) of
Although the exemplary communications adapters of
Also stored in RAM (168) is a communications adapter driver (152). The communications adapter driver (152) is typically a software program that controls the primary communications adapter (167) and the backup communications adapter (171). The communications adapter driver (152) is responsible for receiving and forwarding packets through the primary adapter and passing packets up the protocol stack. When the primary communications adapters (167) fail, the communications adapter driver (152) of
The exemplary communications adapter driver of
The computer (134) of
The example computer of
For further explanation,
The method of
The method of
As will occur to those of skill in the art, the period of time required to initialize ports in a LAN will vary according to many hardware factors and software factors associated with various systems on which primary adapters and backup adapters are installed, as well as specific factors associated with the primary adapters and backup adapters themselves. For further explanation therefore,
The method of
In the method of
If the primary communications adapter is capable of receiving packets, then it is advantageous to activate the primary communications adapter and return the backup adapter to idle. Continuing again with reference to
The method of
The method of
It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present invention without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present invention is limited only by the language of the following claims.
Claims
1. A method for failback to a primary communications adapter, the method comprising:
- receiving, in a driver for a primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter;
- determining that the primary communications adapter is capable of receiving packets;
- setting the backup communications adapter to idle; and
- activating the primary communications adapter.
2. The method of claim 1 wherein determining that the primary communications adapter is capable of receiving packets further comprises:
- sending a packet from the backup communications adapter to the primary communications adapter; and
- receiving the packet in the primary communications adapter.
3. The method of claim 2 wherein sending a packet from the backup communications adapter to the primary communications adapter further comprises broadcasting an ARP packet to all link layer addresses on a LAN.
4. The method of claim 1 wherein determining that the primary communications adapter is capable of receiving packets further comprises predetermining a period of time to initialize ports connecting segments of a LAN.
5. The method of claim 1 wherein the primary communications adapter further comprises a plurality of linked communications adapters.
6. The method of claim 5 wherein the plurality of linked communications adapters further comprise an EtherChannel pseudo-adapter.
7. A system for failback to a primary communications adapter, the system comprising:
- means for receiving, in a driver for a primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter;
- means for determining that the primary communications adapter is capable of receiving packets;
- means for setting the backup communications adapter to idle; and
- means for activating the primary communications adapter.
8. The system of claim 7 wherein means for determining that the primary communications adapter is capable of receiving packets further comprises:
- means for sending a packet from the backup communications adapter to the primary communications adapter; and
- means for receiving the packet in the primary communications adapter.
9. The system of claim 8 wherein means for sending a packet from the backup communications adapter to the primary communications adapter further comprises means for broadcasting an ARP packet to all link layer addresses on a LAN.
10. The system of claim 7 wherein means for determining that the primary communications adapter is capable of receiving packets further comprises means for waiting a predetermined period of time after receiving the link up event for the primary communications adapter.
11. The system of claim 7 wherein the primary communications adapter further comprises a plurality of linked communications adapters.
12. The system of claim 11 wherein the plurality of linked communications adapters further comprise an EtherChannel pseudo-adapter.
13. A computer program product for failback to a primary communications adapter, the computer program product comprising:
- a recording medium;
- means, recorded on the recording medium, for receiving, in a driver for a primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter;
- means, recorded on the recording medium, for determining that the primary communications adapter is capable of receiving packets;
- means, recorded on the recording medium, for setting the backup communications adapter to idle; and
- means, recorded on the recording medium, for activating the primary communications adapter.
14. The computer program product of claim 13 wherein means, recorded on the recording medium, for determining that the primary communications adapter is capable of receiving packets further comprises:
- means, recorded on the recording medium, for sending a packet from the backup communications adapter to the primary communications adapter; and
- means, recorded on the recording medium, for receiving the packet in the primary communications adapter.
15. The computer program product of claim 14 wherein means, recorded on the recording medium, for sending a packet from the backup communications adapter to the primary communications adapter further comprises means, recorded on the recording medium, for broadcasting an ARP packet to all link layer addresses on a LAN.
16. The computer program product of claim 13 wherein means, recorded on the recording medium, for determining that the primary communications adapter is capable of receiving packets further comprises means, recorded on the recording medium, for waiting a predetermined period of time after receiving the link up event for the primary communications adapter.
17. The computer program product of claim 13 wherein the primary communications adapter further comprises a plurality of linked communications adapters.
18. The computer program product of claim 17 wherein the plurality of linked communications adapters further comprise an EtherChannel pseudo-adapter.
Type: Application
Filed: Aug 18, 2004
Publication Date: Feb 23, 2006
Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION (ARMONK, NY)
Inventors: Vinit Jain (Austin, TX), Jorge Rafael Nogueras (Austin, TX)
Application Number: 10/920,906
International Classification: H04L 1/00 (20060101);