Apparatus and method for rapid detection of unidirectional breaks in a network ring
First Claim
1. A ring relay for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the ring relay comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to pass HELLO messages received on the first incoming link to the second outgoing link and to pass HELLO messages received on the second incoming link to the first outgoing link; and
after detecting an OPER DOWN failure on the second incoming link, reacting to the detection of the network failure on the second incoming link by;
imposing a break on the second incoming link so that data packets are blocked from passing into the ring relay but the imposed break does not block any incoming HELLO messages;
imposing a break on the second outgoing link so that data packets are blocked from leaving the ring relay on that link;
sending a type of HELLO message and a control signal out the second outgoing link such that an adjacent node receives a HELLO message to provide assurance that the second outgoing link from that ring relay is operating and to convey to a node other than the ring relay that the ring relay is imposing a bidirectional break so that the virtual break should be removed;
detecting the cessation of the OPER DOWN failure on the second incoming link then resuming operating to pass HELLO messages received on the first incoming link to the second outgoing link; and
delaying the removal of the imposed break for user data on the second outgoing link and on the second incoming link for a time period sufficient to allow the bidirectional network ring to impose a virtual break at a device other than the ring relay.
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Accused Products
Abstract
Normal 802.3 Ethernet requires a tree topology. If a ring or a loop exists, then packets will be forwarded around the ring indefinitely. If the ring is broken, then there is no possibility of packets being propagated forever. This invention shows how to quickly impose a virtual break in the ring such that all nodes can communicate with each other, and how to remove the virtual break when a real failure occurs. This is accomplished by placing intelligent nodes on the ring that work together to virtually break and restore the ring. An embodiment is disclosed that handles a unidirectional break in a communication link where the unidirectional break is not sensed as an OPER DOWN state. This abstract is provided as an aid to those performing prior art searches and not a limitation on the scope of the claims.
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Citations
44 Claims
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1. A ring relay for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the ring relay comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to pass HELLO messages received on the first incoming link to the second outgoing link and to pass HELLO messages received on the second incoming link to the first outgoing link; and
after detecting an OPER DOWN failure on the second incoming link, reacting to the detection of the network failure on the second incoming link by;
imposing a break on the second incoming link so that data packets are blocked from passing into the ring relay but the imposed break does not block any incoming HELLO messages;
imposing a break on the second outgoing link so that data packets are blocked from leaving the ring relay on that link;
sending a type of HELLO message and a control signal out the second outgoing link such that an adjacent node receives a HELLO message to provide assurance that the second outgoing link from that ring relay is operating and to convey to a node other than the ring relay that the ring relay is imposing a bidirectional break so that the virtual break should be removed;
detecting the cessation of the OPER DOWN failure on the second incoming link then resuming operating to pass HELLO messages received on the first incoming link to the second outgoing link; and
delaying the removal of the imposed break for user data on the second outgoing link and on the second incoming link for a time period sufficient to allow the bidirectional network ring to impose a virtual break at a device other than the ring relay. - View Dependent Claims (2, 3, 4, 5)
- the ring relay comprising the following attributes;
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6. A ring relay for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the ring relay comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to pass HELLO messages received on the first incoming link to the second outgoing link and to pass HELLO messages received on the second incoming link to the first outgoing link; and
after detecting a gap in the receipt of HELLO messages on the second incoming link in excess of a set threshold, reacting to the detection of the network failure on the second incoming link by;
imposing a break on the second incoming link so that data packets are blocked from passing into the ring relay but the imposed break does not block any incoming HELLO messages;
imposing a break on the second outgoing link so that data packets are blocked from leaving the ring relay on that link;
sending a type of HELLO message and a control signal out the second outgoing link such that an adjacent node receives a HELLO message to provide assurance that the second outgoing link from that ring relay is operating and to convey to a node other than the ring relay that the ring relay is imposing a bidirectional break so that the virtual break should be removed;
after receiving a HELLO message on the second incoming link, resuming operating to pass HELLO messages received on the first incoming link to the second outgoing link; and
delaying the removal of the imposed break for user data on the second outgoing link and on the second incoming link for a time period sufficient to allow the bidirectional network ring to impose a virtual break at a device other than the ring relay. - View Dependent Claims (7, 8, 9, 10, 11)
- the ring relay comprising the following attributes;
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12. A ring device for use in a bidirectional network ring for a network ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology. the network ring carrying data packets;
- the ring device comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring; and
operating to detect an absence of HELLO protocol packets on the second incoming link in excess of a specified time duration then;
blocking the second outgoing link for user data such that a virtual break is imposed on the second outgoing link;
generating and sending a series of modified HELLO protocol packets on the second outgoing link the sending of modified HELLO protocol packets onto the first and second outgoing link used to trigger immediate corrective action by the bidirectional network ring to remove an existing virtual break from a device other than this ring device; and
detecting a HELLO protocol packet on the second incoming link then;
ceasing the generation and sending of the series of modified HELLO protocol packets on the second outgoing link; and
delaying the removal of the blocking of user data on the second outgoing link for a time period sufficient to allow the bidirectional network ring to impose a virtual break at a device other than this ring device. - View Dependent Claims (13)
- the ring device comprising the following attributes;
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14. A slave arbiter for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the slave arbiter comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to receive HELLO messages on the first incoming link and on the second incoming link and to send HELLO messages on the first outgoing link and the second outgoing link;
maintaining an imposed virtual break on either the first ring port or the second ring port to block the passage of data packets when the network ring is fully functional so as to prevent a data loop; and
reacting to the detection of the link failure on the second incoming link by;
imposing a break on the second incoming link so that data packets are blocked from passing into the slave arbiter but the imposed break does not block any incoming HELLO messages;
imposing a break on the second outgoing link so that data packets are blocked from leaving the slave arbiter on that link;
removing the imposed virtual break from either the first ring port or the second ring port; and
detecting the cessation of the link failure on the second incoming link;
then imposing a virtual break on either the first ring port or the second ring port before removing the imposed break on the second incoming link and the second outgoing link. - View Dependent Claims (15, 16)
- the slave arbiter comprising the following attributes;
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17. A slave arbiter for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the slave arbiter comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to receive HELLO messages on the first incoming link and on the second incoming link and to send HELLO messages on the first outgoing link and the second outgoing link;
maintaining an imposed virtual break on either the first ring port or the second ring port to block the passage of data packets when the network ring is fully functional so as to prevent a data loop; and
after receiving a control signal on the second incoming link indicating that another node on the network ring is imposing a bidirectional break, reacting to the received control signal by;
removing the imposed virtual break from either the first ring port or the second ring port; and
detecting that the node on the network ring that imposed the bidirectional break will soon remove the bidirectional break and responding by imposing a virtual break on either the first ring port or the second ring port. - View Dependent Claims (18, 19, 20)
- the slave arbiter comprising the following attributes;
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21. A ring device for use in a bidirectional network ring for a ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the ring device comprising the following attributes;
having a first ring port in data communication with a first incoming link and a first outgoing link and a second ring port in data communication with a second incoming link and a second outgoing link connected to the network ring;
operating to send HELLO messages onto the first outgoing link and the second outgoing link, the receipt of the HELLO messages on a remote device on the network ring indicating the functioning of the network between the ring device and the remote device; and
reacting to the discernment of the link failure on the second incoming link by;
imposing a break on the second incoming link so that data packets are blocked from passing into the ring device but the imposed break does not block any incoming HELLO messages;
imposing a break on the second outgoing link so that data packets are blocked from leaving the ring device on that link;
sending a type of HELLO message and a control signal out the second outgoing link such that the adjacent node receives a HELLO message to provide assurance that the second outgoing link from that ring device is operating and to convey to the remote device (even if the remote device is not the adjacent node) the control signal that the ring device is imposing a bidirectional break so that the virtual break should be removed;
detecting the cessation of the link failure on the second incoming link then resuming operating to send HELLO messages onto the second outgoing link; and
delaying the removal of the imposed break for user data on the second outgoing link and on the second incoming link for a time period sufficient to allow the bidirectional network ring to impose a virtual break at the remote device. - View Dependent Claims (22, 23, 24, 25, 26)
- the ring device comprising the following attributes;
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27. A network ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network carrying data packets, the network ring comprising:
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A) a Master Arbiter comprising;
a MA first port;
with a first MA incoming link and a first MA outgoing link; and
a MA second port;
with a second MA incoming link and a second MA outgoing link;
B) a Slave Arbiter comprising;
a SA first port normally connected to the MA first port by a full duplex communication connection;
a SA second port normally connected to the MA second port by a full duplex communication connection; and
a SA control system, the SA control system comprising controls over the introduction and removal of a virtual break to prevent the formation of a communication ring for data packets within the network requiring a tree topology through the use of at least one non-forwarding state wherein control traffic is forwarded but data packets are not forwarded;
the SA control system comprising;
at least one rule causing the operation of a SA Port in a slave-forwarding state wherein the port forwards data packets and control traffic received at the port;
at least one rule causing the operation of a SA Port in one of at least one non-forwarding states wherein control traffic is forwarded but data packets are not forwarded;
at least one rule causing the Slave Arbiter to operate when the ring is fully operational such that one SA Port is in a slave-forwarding state and the other SA Port is in a non-forwarding state wherein control traffic is forwarded but data packets are not forwarded;
at least one rule for changing the state of the Slave Arbiter to have both the SA first port and the SA second port acting to forward data packets after receipt of a control signal indicating that a device other than the Slave Arbiter is imposing a bidirectional break in the network ring; and
at least one rule for changing the state of one of the two SA Ports to a non-forwarding state wherein control traffic is forwarded but data packets are not forwarded after discerning that the device other then the Slave Arbiter is going to remove the imposed bidirectional break in the network ring. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. A network device comprising:
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a first port with a first incoming link and a first outgoing link;
a second port with a second incoming link and a second outgoing link;
at least one user port; and
a control system for the network device;
the control system adapted to allow this network device to provide redundant access for the at least one user port to an existing network through a first access device connected to the first port and a second access device in data communication with the first access device and connected to the second port such that a HELLO message transmitted out the first outgoing link can travel via the first access device then the second access device to the second incoming link and a HELLO message transmitted out the second outgoing link can travel via the second access device then the first access device to the first incoming link;
the control system further characterized by;
at least one rule to impose a virtual break on either the first port or the second port when HELLO messages are being received on both ports, the virtual break blocking data packets but not control messages such as HELLO messages;
at least one rule to detect and react to a HELLO timeout on both ports by removing the virtual break from either the first port or the second port so that the at least one user port can have access to the existing network through the first access device connected to the first port if that is possible or through the second access device connected to the second port if that is possible;
at least one rule to detect and react to a HELLO timeout on one port and an OPER DOWN on the other port ports by removing the virtual break from either the first port or the second port so that the at least one user port can have access to the existing network through the first access device connected to the first port if that is possible or through the second access device connected to the second port if that is possible, this at least one rule not necessarily distinct from the rule to detect and react to a HELLO timeout on both ports;
at least one rule to detect a unidirectional break characterized by an OPER DOWN or a HELLO timeout on one port but not the other port and to react by imposing a bidirectional break on the incoming link and the outgoing link on the port with incoming link experiencing an OPER DOWN or a HELLO timeout before removing the virtual break from the port with the virtual break; and
at least one rule to detect and react to the cessation of the unidirectional break characterized by an OPER DOWN or a HELLO timeout by imposing a virtual break on one port before removing bidirectional break. - View Dependent Claims (36)
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37. A method for operating a network ring that is manipulated to provide a virtual break in order to operate within a network requiring a tree topology, the network ring carrying data packets;
- the method comprising;
imposing a virtual break at a first network device, the network device comprised of a first port with a first incoming link and a first outgoing link and a second port with a first incoming link and a second outgoing link, the virtual break imposed whenever the first network device is receiving HELLO messages of a first type on both the first incoming link and the second outgoing link;
removing the virtual break at the first network device upon receipt of a control signal from another device on the network indicating that the another device is imposing a bidirectional break; and
discerning that the another network device is going to stop imposing the bidirectional break and imposing a virtual break. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44)
- the method comprising;
Specification