Method and system for preventing transmission loops in a label switching domain
AssigneeRiverstone Networks, Inc.
InventorBehnam Behzadi
Life of this patent
Estimating the term…
Abstract
Preventing transmission loops in a ring network that utilizes label switching involves generating right side and left side ring packets from an ingress packet and setting right and left TTL values for the packets that prevent the packets from traveling on the same transmission link. Setting the right and left TTL values of the ring packets to values that prevent the packets from traveling on the same link transforms the physical topology of the ring into a logical arc. In an embodiment, the logical arc established by a network node can be dynamically rotated in response to various network conditions to avoid packet transmissions on a particular link of the ring network.
Claims73
A method for preventing transmission loops between a plurality of network nodes that are connected by transmission links to form a ring, wherein each network node on said ring includes a right side ringport that is connected to a right side neighbor and a left side ringport that is connected to a left side neighbor and wherein each of said network nodes in said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, said method comprising:
- generating, at a first one of said plurality of network nodes, a right side packet and a left side packet from an ingress packet;
- and
- setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that prevent said right side packet and said left side packet from traveling on the same transmission link on said ring.
A method for preventing transmission loops between a plurality of network nodes that are connected by transmission links to form a ring, wherein each network node on said ring includes a right side ringport that is connected to a right side neighbor and a left side ringport that is connected to a left side neighbor and wherein each of said network nodes in said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, said method comprising:
- learning, at a first one of said plurality of network nodes, the number (N) of network nodes on said ring;
- generating, at said first network node, a right side packet and a left side packet from an ingress packet;
- and
- setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that are a function of N.
A system for preventing transmission loops in a ring network comprising:
- a plurality of network nodes that are connected by transmission links to form a ring, wherein each of said network nodes on said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, each of said network nodes including:
- a right side ringport that is connected to a right side neighbor;
- left side ringport that is connected to a left side neighbor;
- a packet processor for generating a right side packet and a left side packet from an ingress packet;
- and
- a loop protection module for setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that prevent said right side packet and said left side packet from traveling on the same transmission link on said ring.
A system for preventing transmission loops in a ring network comprising:
- a plurality of network nodes that are connected by transmission links to form a ring, wherein each of said network nodes on said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, each of said network nodes including;
- a right side ringport that is connected to a right side neighbor;
- a left side ringport that is connected to a left side neighbor;
- a packet processor for generating a right side packet and a left side packet from an ingress packet;
- and
- a loop protection module for learning the number (N) of network nodes on said ring and for setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that are a function of N.
A system for preventing transmission loops between a plurality of network nodes that are connected by transmission links to form a ring, wherein each network node on said ring includes a right side ringport that is connected to a right side neighbor and a left side ringport that is connected to a left side neighbor and wherein each of said network nodes in said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, said system comprising:
- a packet processor, located within a first one of said plurality of network nodes, for generating a right side packet and a left side packet from an ingress packet;
- and
- a loop protection module, located within said first network node, for setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that prevent said right side packet and said left side packet from traveling on the same transmission link on said ring.
A system for preventing transmission loops between a plurality of network nodes that are connected by transmission links to form a ring, wherein each network node on said ring includes a right side ringport that is connected to a right side neighbor and a left side ringport that is connected to a left side neighbor and wherein each of said network nodes in said ring utilizes a label switching protocol that includes a label, said label including a label field for carrying a label value and a time-to-live (TTL) field for carrying a TTL value, said system comprising:
- a packet processor, located within a first one of said plurality of network nodes, for generating a right side packet and a left side packet from an ingress packet;
- and
- a loop protection module, located within said first network node, for learning the number (N) of network nodes on said ring and for setting a right side TTL value for said right side packet and a left side TTL value for said left side packet to values that are a function of N.
Dependencies are inferred from the claim text.