Packet propagation and dynamic route discovery apparatus and techniques

• US 5,506,838 A
• Filed: 12/29/1994
• Issued: 04/09/1996
• Est. Priority Date: 12/29/1994
• Status: Expired due to Term

• Current Assignee: EMC Corporation (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Flanagan, Kevin L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US08/366,031
• Time in Patent Office: 467 Days
• Field of Search: 370/54, 370/60, 370/94.1, 370/94.3, 370/85.13, 370/85.14, 370/85.12, 370/85.15, 370/85.9, 370/17
• US Class Current: 370/258
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04L 45/44 Distributed routing

Abstract

A method and apparatus for propagating information, such as node status and routing information, to nodes connected to a network. Each node has at least two ports connected to at least two different data links, such as rings. An information packet is transmitted by one or more nodes to every other node connected directly to a common data link. The receiving node determines whether the packet has been previously received. If the packet has not been previously received, then the receiving node stores the information contained in the packet and modifies the packet for forwarding to other nodes directly connected to the receiving node (and indirectly connected to the transmitting node). If the packet has been previously received, then propagation of the packet is terminated. In one embodiment, nodes learn the network configuration, including the address of other nodes connected to the network and paths for routing packets to such other nodes.

Claims

1. A method for propagating a packet in an n×

m network of nodes, each node being connected to at least two interconnecting segments, comprising the steps of;

transmitting said packet from a transmitting one of said nodes to a first plurality of said nodes connected directly to a first interconnecting segment;

receiving said packet at a receiving one of said first plurality of nodes, said receiving node being further connected to a second interconnecting segment; and

forwarding said packet from said receiving node to a second plurality of nodes connected directly to said second interconnecting segment if information contained in said packet has not been previously received by said receiving node.

2. The method recited in claim 1 further comprising the step of terminating propagation of said packet if said information contained in said packet has been previously received by said receiving node.

3. The method recited in claim 1 further comprising the step of storing said information contained in said packet at said receiving node if said information has not been previously received by said receiving node.

4. The method recited in claim 1 wherein each of said interconnecting segments is a ring and wherein said method further comprises the step of connecting each of said nodes to each of said at least two rings with a QuickRing™

interface circuit.

5. The method recited in claim 1 wherein said packet contains a routing payload and said information contained in said packet includes a route from said transmitting node to said receiving node.

6. The method recited in claim 5 further comprising the step of modifying said routing payload to include said receiving node in said route prior to forwarding said packet.

7. The method recited in claim 1 wherein said packet is a node status packet and said information contained in said packet includes status of said transmitting node.

8. A method for providing nodes of a network with network configuration information, each of said nodes having at least a first port connected to a first interconnecting segment and a second port connected to a second interconnecting segment, wherein each of said nodes is directly connected to ones of said nodes which are connected to one of said first interconnecting segment and said second interconnecting segment and is indirectly connected to ones of said nodes which are not connected to one of said first interconnecting segment and said second interconnecting segment, said method comprising the steps of:

transmitting a discovery packet from a transmitting one of said nodes to said directly connected nodes, said discovery packet containing a route from said transmitting node;

receiving said discovery packet at a receiving one of said directly connected nodes; and

forwarding said discovery packet from said receiving node to said indirectly connected nodes if said route contained in said discovery packet has not been previously received by said receiving node.

9. The method recited in claim 8 further comprising the step of terminating propagation of said packet if said packet has been previously received by said receiving node.

10. The method recited in claim 8 further comprising the step of recording at said receiving node, a slot identifier indicating a slot in which said transmitting node is located, a port identifier indicating the one of said first port and second port of said transmitting node from which said discovery packet is transmitted, and said route contained in said discovery packet.

11. The method recited in claim 8 wherein each of said interconnecting segments is a ring and wherein said method further comprises the step of connecting a QuickRing™

interface circuit to said first and second ports of each of said nodes.

12. The method recited in claim 8 further comprising the step of modifying said discovery packet to identify said receiving node in said route.

13. The method recited in claim 8 wherein said discovery packet transmitting step is performed when said network is initialized.

14. The method recited in claim 8 wherein said transmitting node is a new node added to said network and said discovery packet transmitting step is performed when said new node is added to said network.

15. The method recited in claim 14 further comprising the step of transmitting a node status packet from said receiving node to said new node in response to receipt of said discovery packet from said new node.

16. A data storage subsystem comprising:

a plurality of disk controllers adapted for controlling signal transmission between at least one data storage device and at least one computer; and

a plurality of rings, interconnecting said plurality of disk controllers, each of said plurality of disk controllers being connected to a different set of at least two of said plurality of rings, wherein each of said plurality of disk controllers includes a processor for receiving a packet from a transmitting one of said plurality of disk controllers connected to a first one of said at least two rings to which the respective disk controller is connected and forwarding said packet to one of said plurality of disk controllers connected to a second one of said at least two rings to which the respective disk controller is connected if said information contained in said packet was not previously received by said respective disk controller.

17. The data storage subsystem recited in claim 16 wherein each of said disk controllers further includes a QuickRing™

interface circuit connected to said at least two rings.

18. A method learning the location of nodes within a network comprising a plurality of multiport nodes each having at least first and second ports, wherein each port of each of said multiport nodes is coupled to one of a plurality of data links, comprising the steps of:

in a first transmitting step, transmitting a first packet from a first multiport node through at least one of said first and second ports to a first one of said plurality of data links, wherein said packet contains routing information comprising the address of said first multiport node and the port identification for the respective port of said multiport node;

receiving said first packet over said first one of said plurality of data links at a second multiport node through one of said at least first and second ports of said second one of said plurality of multiport nodes;

analyzing at said second multiport node said first packet to ascertain routing information contained within said first packet; and

in a second transmitting step, transmitting a second packet from said second multiport node to a second data link coupled to another one of said at least first and second ports of said second multiport node if said routing information contained in said first packet is not recognized by said second node, wherein said second packet contains said first packet routing information and routing information for said multiport node comprising the address of said second multiport node and the port identification for the respective port of said second multiport node.

19. The method recited in claim 18 further comprising the step of repeating said receiving step, said analyzing step, and said second transmitting step at each of said plurality of multiport nodes.

20. The method recited in claim 18 further comprising the step of storing routing information contained in said first packet in a table within said second multiport node.