Relative addressing for network elements

• US 7,310,688 B1
• Filed: 08/29/2000
• Issued: 12/18/2007
• Est. Priority Date: 08/30/1999
• Status: Expired due to Term

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Chin, Hon Wah
• Primary Examiner(s): LIN, KENNY S
• Application Number:
  US09/650,254
• Time in Patent Office: 2,667 Days
• Field of Search: 709/249, 709/238, 709/241, 370/221, 370/254, 370/400, 370/460, 370/248, 370/397, 370/258, 370/351, 379/219
• US Class Current: 709/252
• 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 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/34 Source routing

Abstract

A relative address protocol for communicating message packets along a linear chain network or quasi-linear chain network is disclosed. The protocol includes a relative destination address field that includes a counter having a preselected initial value at a source node. The initial value is a function of the desired number of node hops that the message packet should travel from the source node. The counter is adjusted in value at each subsequent node by a preselected step in value. When the counter value reaches a trigger value the message packet is accepted by a destination node. In a preferred embodiment, a relative source address field stores the initial value so that the destination node may return a status message to the source node.

Claims

1. An address protocol for forwarding a message packet from a source node to a destination node along a sequence of communicatively coupled nodes functioning as a linear chain network, the address protocol comprising:

a relative source address field programmed with an initial value at the source node corresponding to a destination node that is a preselected number of nodes away from the source node along the linear chain network;

a relative destination address field containing a counter and a directional code corresponding to a port of the source node from which the message packet is to be sent along the linear chain network;

wherein the counter is incremented by a preselected step in value at each node the message packet is forwarded to along the chain network until the counter reaches the initial value, thereby indicating that the destination node has been reached;

an identifier field containing an identifier, wherein the identifier indicates whether the message packet contains relative address protocol information;

wherein the destination node does not require address information in addition to the counter reaching the initial value to accept the message packet; and

wherein, when in the sequence of communicatively coupled nodes functioning as a linear chain network, each message packet encounters a branching node having two or more output ports before reaching the destination node, the branching node has programming configured to return a message indicating that the branching node was reached and reporting the number of hops the branching node is away from the source node.

2. The protocol of claim 1, wherein the initial value is an integer having an absolute value equal to the desired number of node hops and the counter is incremented by a step in value of one at each node.

3. The protocol of claim 2, wherein the counter is initially set to zero and the counter is counted up by one at each node hop until the initial value is reached.

4. The protocol of claim 1, wherein the initial value is a linear function of the desired number of node hops.

5. The protocol of claim 1, wherein at least one node in the linear chain is a regenerator element.

6. The protocol of claim 1, wherein the chain network is a virtual chain network.

7. The protocol of claim 1, wherein the chain network comprises a portion of a ring network.

8. A method of sending a message packet along a portion of a network functioning as a linear chain network from a source node to a destination node using an address protocol having an identifier field containing an identifier, wherein the identifier indicates whether the message packet contains relative address protocol information, a relative source address field for storing an initial value, and a relative destination address field containing a counter and a directional code corresponding to a port of the source node from which the message packet is to be sent along the linear chain network, the method comprising the steps of:

selecting the initial value to be a function of a desired number of node hops along the linear chain network from the source node;

programming the relative source address field to have the initial value;

incrementing the counter by a preselected step in value at each node that the message packet is forwarded to;

accepting the message packet at a destination node when the counter value reaches the initial value, without requiring address information in addition to the counter reaching the initial value to accept the message packet,

wherein the preselected step in value is chosen so that the counter reaches the initial value when the packet has completed the desired number of node hops; and

wherein, when in the sequence of communicatively coupled nodes functioning as a linear chain network, each message packet encounters a branching node having two or more output ports before reaching the destination node, the branching node has programming configured to return a message indicating that the branching node was reached and reporting the number of hops the branching node is away from the source node.

9. The method of claim 8, wherein the message packet comprises a status query message and further comprising the steps of:

requesting the destination node to send a status message packet having a second relative source address field and a second counter in a direction along the chain back to the source node;

programming the second relative source address field to have the initial valued-incrementing the second counter by the preselected step in value at each node that the message packet is forwarded to; and

accepting the status message packet when the counter reaches the initial value, wherein the status message packet is returned to the source node.

10. The method of claim 9, wherein at least one of the nodes of the chain includes a regenerator element.

11. The method of claim 9, further comprising the steps of:

selecting a return message;

transmitting the return message in the direction to the source node;

incrementing the second counter by the preselected step in value at each node that the message packet is forwarded to; and

accepting the return message packet at the source node when the second counter reaches the initial value.

12. The method of claim 8, further comprising the step of:

detecting a fault in a linear chain of regenerator nodes using the relative address protocol by;

sending a first status query message packet requesting a return status message from a destination node at least one node hop from the source node;

sending at least one subsequent status query message packet requesting a return status message from another destination node corresponding to a different number of node hops from the source node and recording whether the return status message is received at the source node; and

determining the node the greatest number of node hops from the source node replying to the status query message directed to it,

wherein a fault is isolated to a portion of the chain network subsequent to the node the greatest number of node hops from the source node returning the corresponding status message.

13. A method of sending a message packet along a chain network having regenerator nodes from a source node to a destination node using an address protocol having an identifier field containing an identifier, wherein the identifier indicates whether the message packet contains relative address protocol information, a relative source address field for storing an initial value, and a relative destination address field containing a counter and a directional code corresponding to a port of the source node from which the message packet is to be sent along the linear chain network, the method comprising the steps of:

selecting the initial value to be a function of a desired number of node hops along the linear chain from the source node;

incrementing the counter by a preselected step in value at each node that the message packet is forwarded to;

accepting the message packet at a destination node when the counter value reaches the initial value, without requiring address information in addition to the counter reaching the initial value to accept the message packet,

wherein the preselected step in value is chosen so that the counter reaches the initial value when the packet has completed the desired number of node hops; and

wherein, when in the sequence of communicatively coupled nodes functioning as a linear chain network, each message packet encounters a branching node having two or more output ports before reaching the destination node, the branching node has programming configured to return a message indicating that the branching node was reached and reporting the number of hops the branching node is away from the source node.

14. The method of claim 13, wherein the message packet comprises a status query message and further comprising the steps of:

requesting the destination node to send a status message packet having a second relative source address field and a second counter back to the source node;

programming the second relative source address field to have the initial valued-incrementing the second counter by the preselected step in value at each node that the message packet is forwarded to; and

accepting the message packet when the second counter reaches the initial value, wherein the status message packet is returned to the source node.

15. The method of claim 14, further comprising the steps of:

sending a plurality of the status query messages to a plurality of destination nodes, the destination nodes corresponding to different initial values indicating that the destination nodes are each a different number of node hops from the source node;

receiving the status message packets from responding destination nodes; and

determining the relative distance of responding nodes as a function of the initial value corresponding to each responding node,

wherein a fault is isolated to a part of the network subsequent to the responding active node the greatest number of node hops from the source node.