SCSI-based storage area network having a SCSI router that routes traffic between SCSI and IP networks Number:7,437,477 from the United States Patent and Trademark Office (PTO) owispatent A system and method for accessing Storage Area Networks over an IP network. A SCSI request is generated and encapsulated in one or more IP packets. The encapsulated SCSI request is routed over an IP network and received by a storage router. The storage router extracts the SCSI request from the one or more IP packets and routes the extracted SCSI request through a virtual SCSI router to the storage area network.<H networks, between, SCSI, based, stor, 7437477.html, Patent, pto, 7437477

Title: SCSI-based storage area network having a SCSI router that routes traffic between SCSI and IP networks

Abstract: A system and method for accessing Storage Area Networks over an IP network. A SCSI request is generated and encapsulated in one or more IP packets. The encapsulated SCSI request is routed over an IP network and received by a storage router. The storage router extracts the SCSI request from the one or more IP packets and routes the extracted SCSI request through a virtual SCSI router to the storage area network.

Patent Number: 7,437,477 Issued on 10/14/2008 to Kuik, et al.

Inventors: Kuik; Timothy J. (Lino Lakes, MN), Thompson; David Patrick (Rogers, MN), Bakke; Mark A. (Maple Grove, MN), Haapala; Clayton Stuart (Minnetonka, MN), De Groote; Stephen P. (Maple Grove, MN), Johnson; Craig A. (Maple Grove, MN), Muchow; James D. (Zimmerman, MN)
Assignee: Cisco Technology, Inc. (San Jose, CA)

Appl. No.: 11/622,436

Filed: January 11, 2007

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
10128656	Jan., 2007	7165258

Current U.S. Class: 709/238 ; 719/326; 719/327

Current International Class: G06F 15/173 (20060101)

Field of Search: 719/326,327 710/11,62,72,305 370/466,467 709/238,250

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Primary Examiner: Lim; Krisna
Attorney, Agent or Firm: Schwegman, Lundberg & Woessner, P.A.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 10/128,656, filed Apr. 22, 2002, now U.S. Pat. No. 7,165,258, issued on Jan. 16, 2007, entitled "SCSI-BASED STORAGE AREA NETWORK HAVING A SCSI ROUTER THAT ROUTES TRAFFIC BETWEEN SCSI AND IP NETWORKS", which is related to the following co-pending, commonly assigned U.S. patent applications:

Application Ser. No. 10/122401, filed Apr. 11, 2002, entitled "METHOD AND APPARATUS FOR SUPPORTING COMMUNICATIONS BETWEEN NODES OPERATING IN A MASTER-SLAVE CONFIGURATION", which is a continuation of application Ser. No. 09/949,182, filed Sep. 7, 2001, entitled "METHOD AND APPARATUS FOR SUPPORTING COMMUNICATIONS BETWEEN NODES OPERATING IN A MASTER-SLAVE CONFIGURATION"; application Ser. No. 10/094,552, filed Mar. 7, 2002, entitled "METHOD AND APPARATUS FOR EXCHANGING HEARTBEAT MESSAGES AND CONFIGURATION INFORMATION BETWEEN NODES OPERATING IN A MASTER-SLAVE CONFIGURATION"; application Ser. No. 10/131,275, filed even date herewith, entitled "METHOD AND APPARATUS FOR CONFIGURING NODES AS MASTERS OR SLAVES"; application Ser. No. 10/131,274, filed even date herewith, entitled "METHOD AND APPARATUS FOR TERMINATING APPLICATIONS N A HIGH-AVAILABILITY NETWORK"; application Ser. No. 10/131,793, filed even date herewith, entitled "VIRTUAL SCSI BUS FOR SCSI-BASED STORAGE AREA NETWORK"; application Ser. No. 10/131,782, filed even date herewith, entitled "VIRTUAL MAC ADDRESS SYSTEM AND METHOD"; application Ser. No. 10/128,655, filed even date herewith, entitled "SYSTEM AND METHOD FOR CONFIGURING FIBRE-CHANNEL DEVICES"; application Ser. No. 10/131,789, filed even date herewith, now U.S. Pat. No. 6,895,461, issued on May 17, 2005, entitled "METHOD AND APPARATUS FOR ASSOCIATING AN IP ADDRESS AND INTERFACE TO A SCSI ROUTING INSTANCE"; application Ser. No. 10/128,657, filed even date herewith, entitled "METHOD AND APPARATUS FOR EXCHANGING CONFIGURATION INFORMATION BETWEEN NODES OPERATING IN A MASTER-SLAVE CONFIGURATION"; and application Ser. No. 10/128,993, filed even date herewith, now U.S. Pat. No. 7,188,194, issued on Mar. 6, 2007, entitled "SESSION-BASED TARGET/LUN MAPPING FOR A STORAGE AREA NETWORK AND ASSOCIATED METHOD", all of the above of which are hereby incorporated by reference in their entirety.

Claims

What is claimed is:

1. A storage router, comprising: a management module having a management interface, wherein the management interface receives commands and wherein the management module configures the storage router as a function of the received commands; an IP network interface; a SCSI network interface capable of transferring data on a storage network running a SCSI protocol; and a SCSI router, wherein the SCSI router includes means for receiving encapsulated SCSI packets from the IP network interface, means for extracting the SCSI packet from the encapsulated SCSI packet and means for forwarding the SCSI packet to the SCSI network interface, and means for executing a discovery process to determine devices connected to the storage network; wherein the SCSI router maps physical storage devices to iSCSI targets.

2. The storage router of claim 1, wherein the management module includes a high availability interface.

3. The storage router of claim 1, wherein the management interface receives commands via the IP network interface.

4. The storage router of claim 1, wherein the SCSI network interface includes a Fibre Channel interface.

5. A storage router, comprising: a management module having a management interface, wherein the management interface receives commands and wherein the management module configures the storage router as a function of the received commands; an IP network interface; a SCSI network interface capable of transferring data on a storage network running a SCSI protocol; and a plurality of virtual SCSI routers, wherein each virtual SCSI router includes means for receiving encapsulated SCSI packets from the IP network interface, means for extracting the SCSI packet from the encapsulated SCSI packet and means for forwarding the SCSI packet to the SCSI network interface and means for executing a discovery process to determine devices connected to the storage network; wherein each virtual SCSI router maps physical storage devices to iSCSI targets.

6. The storage router of claim 5, wherein the SCSI network interface includes an iSCSI interface.

7. The storage router of claim 5, wherein the management module includes a high availability interface.

8. The storage router of claim 5, wherein the management interface receives commands via the IP network interface.

9. The storage router of claim 5, wherein the SCSI network interface includes a parallel SCSI interface.

10. A computer system capable of communicating across an IP network, comprising: a computer, wherein the computer includes a network interface capable of transferring data across the IP network; and a storage router, wherein the storage router includes: a management module having a management interface, wherein the management interface receives commands and wherein the management module configures the storage router as a function of the received commands; an IP network interface; a SCSI network interface for connecting to a storage network running a SCSI protocol; a means for executing a discovery process to determine devices connected to the storage network; and a virtual SCSI router, wherein the virtual SCSI router receives encapsulated SCSI packets from the computer via the IP network interface, extracts the SCSI packet from the encapsulated SCSI packet and forwards the SCSI packet to the SCSI network interface; wherein the virtual SCSI router maps physical storage devices to iSCSI targets.

11. The computer system of claim 10, wherein the management module includes a high availability interface.

12. The computer system of claim 10, wherein the management interface receives commands via the IP network interface.

13. The computer system of claim 10, wherein the storage router is coupled between a Gigabit Ethernet interface and a Fibre Channel interface and configured to perform as an IPv4 router.

14. A method of accessing data stored on a storage network, comprising: inserting an iSCSI driver in the protocol stack of a server; generating a SCSI request within the server and passing the SCSI request to the iSCSI driver; executing instructions in the iSCSI driver to encapsulate the SCSI request in one or more IP packets; routing the encapsulated SCSI request over an IP network; receiving the encapsulated SCSI request; extracting the SCSI request from the one or more IP packets; and routing the SCSI request through a virtual SCSI router to the storage network, wherein routing includes mapping physical storage devices to iSCSI targets.

15. The method of claim 14, wherein routing the SCSI request through a virtual router includes executing a discovery process to determine devices connected to the storage network.

16. The method of claim 14, wherein receiving the encapsulated SCSI request includes verifying that the encapsulated SCSI request was received at a predefined IP network interface.

17. A storage router system having a plurality of storage routers, including two or more managed storage routers, wherein each of the managed storage routers comprises: a management module having a management interface, wherein the management interface includes a high availability interface, wherein the management module receives commands via the management interface and configures the storage router as a function of the received commands; an IP network interface; a SCSI network interface capable of transferring data on a storage network running a SCSI protocol; and a SCSI router, wherein the SCSI router includes means for receiving encapsulated SCSI packets from the IP network interface, means for extracting the SCSI packet from the encapsulated SCSI packet and means for forwarding the SCSI packet to the SCSI network interface and means for executing a discovery process to determine devices connected to the storage network; wherein the high availability interface of each managed storage router is communicatively connected to the high availability interface of each of the other managed storage routers; and wherein the SCSI router maps physical storage devices to iSCSI targets.

18. The storage router system of claim 17, wherein the management module includes a high availability interface.

19. The storage router system of claim 17, wherein the management interface receives commands via the IP network interface.

20. The storage router system of claim 17, wherein the SCSI network interface includes a Fibre Channel interface.

Description

COPYRIGHT NOTICE/PERMISSION

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the drawings, the software descriptions/examples, and data as described below: Copyright .COPYRGT. 2001-2002, Cisco Systems, Inc., All Rights Reserved.

FIELD OF THE INVENTION

This invention relates generally to data storage, and more particularly to a system and method for making SCSI-based devices accessible across a network.

BACKGROUND OF THE INVENTION

As electronic business (ebusiness) grows, so does the need for better ways to share and manage large amounts of data. The amount of data storage required by today's ebusinesses is staggering. A good example of this is mail.com, which grew to 60 terabytes of storage in just 45 days.

Today almost all client access to large scale storage is accomplished by sending requests through general-purpose servers that connect an IP network (e.g., LAN or WAN) to the storage network (e.g., a Storage Area Networks (SAN)). Storage Area Networks provide access to large amounts of data storage.

SANs, however, are complex systems. A recent Enterprise Management Associates (EMA) study of 187 IT professionals stated, however, that only 20% of customers had installed SANs by the end of 1999. 46% of the respondents in that survey said they had no plans to install a SAN. The top four reasons for delaying or for deciding not to install a SAN were: high implementation costs, lack of qualified staff, technology immaturity, and lack of standards. Furthermore, although SANs typically are very good at connecting native storage resources, they are distance-limited and have no knowledge of IP and its priorities.

Often, customers outsource their storage to a SSP provider who will manage their storage needs for a predetermined fee. A typical application would use a distributed Fibre-Channel (FC) network to connect an IP network to FC devices located at either a local or a remote site. In this example, the S SP provides the entire storage infrastructure on the customers premises. While FC has numerous advantages, it lacks network management tools and is significantly higher priced than comparable Ethernet products. Most importantly, due to lack of network security, the SSP must create a separate Storage Area Network for each customer at the SSP to separate data from multiple customers.

For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a system and method for accessing SANs over an IP network in a more integrated fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a SCSI-based storage system according to the present invention;

FIG. 2 shows a hardware block diagram of one embodiment of storage router 110;

FIG. 3 is a function block diagram of an exemplary system 100 having storage router 110;

FIG. 4 is a block diagram representing the concept of storage mapping and access control;

FIG. 5 is a block diagram of internal functions of storage router 110;

FIG. 6 shows an exemplary storage-router cluster 300 showing SCSI routing;

FIG. 7 shows the headers added to the iSCSI and to the fibre-channel commands and data;

FIG. 8 is a block diagram of a SAN 100 showing naming and mapping;

FIG. 9 is a block diagram of a SAN 100 showing SCSI encapsulation;

FIG. 10 is a block diagram of a SAN 100 showing naming and mapping;

FIG. 11 shows a block diagram of a sample storage-router network 200; and

FIG. 12 illustrates a device database which could be used in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

Some portions of the detailed descriptions which follow are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, terms such as "processing" or "computing" or "calculating" or "determining" or "displaying" or the like, refer to the actions and processes of a computer system, or similar computing device, to manipulate and transform data. Unless specifically stated otherwise, the data being manipulated is stored as physical (e.g., electronic) representations within computer system registers and memories, or within other information storage, transmission or display devices. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

A SCSI-based storage system is shown in FIG. 1. The Small Computer Systems Interface (SCSI) is a popular family of protocols for communicating with I/O devices, especially storage devices. In system 100 of FIG. 1, one or more servers 127, 128 access a storage network 139 via an IP network 129. A server issues a SCSI request and encapsulates the SCSI request in one or more IP packets. The encapsulated SCSI request is routed across IP network 129 to a storage router 110, where the SCSI request is extracted from the one or more IP packets. The extracted SCSI request is then routed through storage network 139 to a storage device 140. The server, therefore, can access storage device 140 as if it were directly attached to the storage device.

As is shown in FIG. 1, in one embodiment, system 100 can be viewed as performing three distinct actions for each request 101. First, SCSI requests are transported over an IP network. Second, SCSI requests are routed through storage router 110 to storage network 139. Finally, the SCSI request is transported across storage network 139 to a SCSI device 140.

Similarly, as is shown in the embodiment in FIG. 1, system 100 can be viewed as performing three distinct actions for each response. First, SCSI responses are transported from SCSI device 140 across storage network 139. Second, SCSI responses are routed through storage router 110 to IP network 129. Finally, the SCSI response is transported across IP network 129 to one of the servers 127, 128.

In one embodiment, a driver in each server 127, 128 is used to encapsulate SCSI commands into one or more IP packets. Such an embodiment is shown in FIG. 9. In the embodiment shown in FIG. 9, the driver implements the iSCSI specification. The iSCSI protocol is a transport protocol for SCSI that operates on top of TCP. It is described in "draft-ietf-ips-iSCSI-12.txt" on the Internet Engineering Task Force web site.

The iSCSI protocol aims to be fully compliant with the requirements laid out in the SCSI Architecture Model-2 (SAM2) document. The iSCSI protocol is a mapping of the SCSI remote procedure invocation model (see the SAM document) over the TCP protocol. SCSI commands are carried by iSCSI requests and SCSI responses and status are carried by iSCSI responses. iSCSI also uses the request response mechanism for iSCSI protocol mechanisms.

Returning to FIG. 9, an end user initiates a request for data from computer 132. Computer 132 sends the request via one or more IP packets 131 to server 128. Server 128 creates one or more SCSI block requests based on the file request received from computer 132, encapsulates the SCSI block requests within IP packets 133 and sends the encapsulated packets 133 across IP network 129 to storage router 110. Storage router 110 extracts the SCSI block requests and sends the requests across storage network 139 to storage device 140. In the embodiment shown, storage network 139 is a Fibre-Channel (FC) network and the SCSI block requests are sent across storage network 139 as Fibre-Channel packets 135.

One embodiment of storage router 110 is shown in FIG. 2. Storage router 110 of FIG. 2 includes a processor 170, which runs the storage router 110 software, a Gigabit Ethernet interface 106, which provides connection to IP network 129 for access by servers 127, 128 and a Fibre Channel interface 104, which provides connection to storage network 139 for access to storage devices 140.

In the embodiment shown in FIG. 2, storage router 110 also includes a High Availability (HA) interface 148, which provides a physical connection for high availability communication with another storage router 110 and management interfaces 158 and 168, which provide connections for managing storage router 110. As shown in FIG. 2, HA interface 148 includes a 10/100 Ethernet interface. HA interface 148 will be described in more detail below.

In the embodiment shown in FIG. 2, the management interfaces include an RS-232 interface 168 for local console connection and a 10/100 Ethernet interface 158 for local or network connection.

In one such embodiment, processor 170 is implemented as a 750PowerPC microprocessor 171 running at 500 MHz and having 512 KB of local L2 cache 172. Microprocessor 171 connects through bus 176 to a 64-bit, 66-MHz PCI bridge 173 that controls 128 MB to 1 GB of SDRAM 174. Bridge 173 also controls interfaces 148,158 and 168 and a PCI bus 177.

In the embodiment shown in FIG. 2, router 110 is implemented in a 1 U rack-mountable chas