Interconnecting forwarding contexts using u-turn ports
First Claim
Patent Images
1. A packet switching device comprising:
- a switching mechanism;
a first line card associated with a first forwarding context configured to identify forwarding information for packets based on a first forwarding information base stored on the first line card, the first line card including a first ingress port and a first egress port; and
a second line card associated with a second forwarding context configured to identify forwarding information for packets based on a second forwarding information base stored on the second line card, the second line card including within the second forwarding context a U-turn port comprising a second ingress port and a second egress port;
wherein the packet switching device is configured to automatically forward all packets, received on the second egress port from the switching mechanism and not dropped at the second egress port, to the second ingress port from the second egress port;
wherein the switching mechanism is configured to communicate packets among a plurality of line cards of the packet switching device, the plurality of line cards including the first line card and the second line card; and
wherein the first line card is configured to forward packets, identified to be sent to the second forwarding context or the second line card based on the first forwarding information base, from the first ingress port over the switching mechanism to the second egress port of the U-turn port via the switching mechanism without traversing an ingress port of the second line card.
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Abstract
Disclosed are, inter alia, methods, apparatus, computer-readable media, mechanisms, and means for interconnecting forwarding contexts using U-turn ports. A U-turn port typically comprises an egress port and an ingress port such that packets placed in the egress port are automatically forwarded to the ingress port. Other forwarding contexts are able to communicate packets to a next-destination forwarding context by sending these packets to the U-turn port of the next-destination forwarding context.
32 Citations
23 Claims
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1. A packet switching device comprising:
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a switching mechanism; a first line card associated with a first forwarding context configured to identify forwarding information for packets based on a first forwarding information base stored on the first line card, the first line card including a first ingress port and a first egress port; and a second line card associated with a second forwarding context configured to identify forwarding information for packets based on a second forwarding information base stored on the second line card, the second line card including within the second forwarding context a U-turn port comprising a second ingress port and a second egress port;
wherein the packet switching device is configured to automatically forward all packets, received on the second egress port from the switching mechanism and not dropped at the second egress port, to the second ingress port from the second egress port;wherein the switching mechanism is configured to communicate packets among a plurality of line cards of the packet switching device, the plurality of line cards including the first line card and the second line card; and wherein the first line card is configured to forward packets, identified to be sent to the second forwarding context or the second line card based on the first forwarding information base, from the first ingress port over the switching mechanism to the second egress port of the U-turn port via the switching mechanism without traversing an ingress port of the second line card. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method, comprising:
performing operations by a packet switching device, including a switching mechanism;
packet forwarding hardware operating a plurality of forwarding contexts on one or more line cards, including a first forwarding context and a second forwarding context; and
memory associated with the first forwarding context configured to store a first forwarding information base and memory associated with the second forwarding context configured to store a second forwarding information base;
wherein the first forwarding context is associated with a first ingress port and a first egress port for respectively receiving packets and transmitting packets;
wherein the second forwarding context is associated with a U-turn port comprising a second ingress port and a second egress port within the second forwarding context; and
wherein said operations include;identifying forwarding information for packets associated with the first forwarding context based on the first forwarding information base; identifying forwarding information for packets associated with the second forwarding context based on the second forwarding information base; automatically forwarding all packets, that are received on the second egress port from the switching mechanism and not dropped at the second egress port, to the second ingress port from the second egress port; communicating packets by the switching mechanism among the plurality of forwarding contexts; and forwarding packets, identified in the first forwarding context based on the first forwarding information base to be sent to the second forwarding context, from the first ingress port over the switching mechanism to the second egress port of the U-turn port without traversing an ingress port of the second forwarding context. - View Dependent Claims (16, 17, 18, 19)
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20. A packet switching device comprising:
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a switching mechanism; and one or more line cards configured to forward packets according to a first forwarding context configured to identify forwarding information for packets based on a first forwarding information base, the first forwarding context being associated with a first ingress port and a first egress port for respectively receiving packets and transmitting packets, the first forwarding context including a first U-turn port comprising a particular ingress port and a particular egress port within the first forwarding context;
wherein the packet switching device is configured to automatically forward all packets, that are received on the particular egress port from the switching mechanism and not dropped at the particular egress port, to the particular ingress port from the particular egress port; andwherein said one or more line cards configured to forward packets according to a second forwarding context configured to identify forwarding information for packets based on a second forwarding information base, the second forwarding context being associated with a second U-turn port comprising a second ingress port and a second egress port within the second forwarding context;
wherein the packet switching device is configured to automatically forward all packets, that are received on the second egress port from the switching mechanism and not dropped at the second egress port, to the second ingress port from the second egress port;wherein the switching mechanism is configured to communicate packets among a plurality of forwarding contexts of said one or more line cards, with the plurality of forwarding contexts including the first and the second forwarding contexts; wherein the first forwarding context is configured to forward packets identified, based on the first forwarding information base, to be sent to the second forwarding context from the particular ingress port of the first U-turn over the switching mechanism to the second egress port of the second U-turn port via the switching mechanism without traversing an ingress port of the second forwarding context. - View Dependent Claims (21, 22, 23)
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Specification