Supporting local IB packet communication between separate subnets

• US 20040022257A1
• Filed: 07/30/2002
• Published: 02/05/2004
• Est. Priority Date: 07/30/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Green, Howard, Forbes, Brian, Costantino, Lino
• Granted Patent: US 7,221,676 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 41/044 comprising hierarchical management structures
• CPC Class Codes: H04L 41/046 comprising network management agents or mobile agents therefor
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/60 Router architectures
• CPC Class Codes: H04L 45/742 Route cache; Operation thereof

Abstract

A router is disclosed for supporting local-level communication between separate subnets managed by different subnet managers. The router preferably makes one or more end nodes from one subnet “visible” to the subnet manager of another subnet. The end nodes may consequently be identified by one local identifier (LID) value in one subnet, but by another LID value in a different subnet. In a preferred embodiment, the router accepts from a first subnet local IB packets directed to end nodes made visible from a second subnet, and processes the local IB packet to convert the first subnet LID values for destination and source end nodes to second subnet LID values for these end nodes.

Claims

1. A network that comprises:

a first subnet having one or more end nodes;

a second subnet having one or more end nodes, wherein end nodes in the first and second subnets each have a global identifier and an assigned local identifier; and

a router configured to process globally-routed packets traveling between the first and second subnets to determine appropriate local identifiers from global identifiers of destination end nodes,

wherein the router is further configured to process locally-routed packets traveling between the first and second subnets to determine appropriate local identifiers from local identifiers of destination end nodes.

2. A network that comprises:

a first subnet having a first subnet manager that assigns a local identifier to each end node in the first subnet, and that assigns a local identifier to a first remote end node;

a second subnet having a second subnet manager that assigns a local identifier to each end node in the second subnet, and that assigns a local identifier to a second remote end node, wherein the second subnet includes the first remote end node, and the first subnet includes the second remote end node; and

a router configured to receive locally-routed packets directed from the second remote end node to the first remote end node, wherein the router is configured to convert first subnet local identifiers of the first and second remote nodes in the local route headers to second subnet local identifiers of the first and second remote nodes before providing the locally-routed packets to the second subnet.

3. The network of claim 2, wherein the router is further configured to receive other locally-routed packets directed from the first remote node to the second remote node, and to convert second subnet local identifiers of the first and second remote nodes in the local route headers to first subnet local identifiers of the first and second remote nodes before providing the other locally-routed packets to the first subnet.

4. The network of claim 2, wherein the router is further configured to emulate one or more switches that connect the first remote node to the first subnet.

5. The network of claim 2, wherein the router is further configured to emulate one or more switches that connect a selected subset of end nodes from the second subnet to the first subnet.

6. The network of claim 2, wherein the router includes an internal subnet configured to transport Infiniband packets between the router ports based on contents of local route headers in the packets.

7. The network of claim 6, wherein a first router port connected to the first subnet determines the second subnet local identifier for the first remote end node.

8. The network of claim 7, wherein the first router port encapsulates the locally-routed packets in raw datagrams with new local route headers, and wherein the internal subnet transports the raw datagram packets to a second router port that de-encapsulates the locally-routed Infiniband packets and provides the de-encapsulated locally-routed packets to the second subnet.

9. The network of claim 8, wherein the second router port further determines the second subnet local identifier for the second remote end node before providing the de-encapsulated locally-routed packets to the second subnet.

10. The network of claim 2, further comprising:

a second router attached to the second subnet, wherein the first router is attached to the first subnet, and

wherein the second router is configured to cooperate with the first router to communicate locally-routed packets traveling between the first and second remote end nodes.

11. The network of claim 10, wherein the routers are configured to emulate one or more switches that connect the first and second remote end nodes.

12. The network of claim 2, wherein the first router is configured to encapsulate the locally-routed packets into raw datagrams after converting the first subnet local identifiers into second subnet local identifiers, and wherein the first router directs the raw datagrams to the second router, which de-encapsulates the locally-routed packets before providing the locally-routed packets to the second subnet.

13. A method of allowing local communications between Infiniband (IB) end nodes in different subnets coupled by a router, the method comprising configuring the router for:

receiving a packet from a first subnet;

determining whether the packet is a local IB packet or a global IB packet;

if the packet is a local IB packet, determining whether the packet includes a destination local identifier (LID) value assigned to an end node in a second subnet by a subnet manager in the first subnet, and if so, converting the destination LID value to a LID value assigned to said end node by a subnet manager in the second subnet.

14. The method of claim 13, further comprising configuring the router for:

encapsulating the packet in a raw datagram if the packet is a local IB packet and includes a destination LID assigned by the first subnet manager to the end node in the second subnet.

15. The method of claim 14, further comprising configuring the router for:

communicating the encapsulated packet across an IB subnet to a second router that de-encapsulates the packet before providing the packet to the second subnet.

16. The method of claim 13, wherein the router is further configured to convert a source LID value in the packet from a value assigned by the subnet manager to a source end node in the first subnet into a LID value assigned by a subnet manager in the second subnet to the source end node.

17. The method of claim 13, further comprising configuring the router for:

dropping the packet if the packet is a local IB packet and the destination LID value was not assigned by the first subnet manager to an end node in another subnet.

18. The method of claim 13, further comprising configuring the router for:

if the packet is a global IB packet, determining a new local route header with a destination LID value based on a destination GID value in the packet.

19. The method of claim 18, further comprising configuring the router for:

emulating one or more switches that connect the end node in the second subnet to the first subnet, thereby allowing the first subnet manager to assign a first subnet LID value to the end node.