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Use of a Bit in the Packet Header for Bandwidth Pool Exhaustion Notification

IP.com Disclosure Number: IPCOM000028689D
Original Publication Date: 2004-Jun-25
Included in the Prior Art Database: 2004-Jun-25
Document File: 1 page(s) / 18K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In a Quality of Service (QoS) routed network each traffic engineering class (TE class) using a link has a different allocation of bandwidth. If this bandwidth fills up, the nodes in the network have to be notified because the link will soon be unable to admit calls of that TE class. Up to now this notification is done via link state updates triggered by thresholds or timers. It is hereby proposed to use one of the unused bits in the packets that flow through the nodes. If one of the nodes detects a bandwidth pool filling up, it sets this bit to indicate that the bandwidth pool is almost full. The packet is then routed to its destination normally. When the destination detects the set bit, it then sets the links used by that tunnel to “full state”. When the destination receives a packet with a “bandwidth pool full” bit which is not set, the links are set to “free state” again. The nodes should use thresholds and dampening for changing the state of the links to avoid unnecessary oscillating. This method provides a more exact and up-to-date picture of the network and its actual load.

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Use of a Bit in the Packet Header for Bandwidth Pool Exhaustion Notification

Idea: Richard Edwin, GB-Romsey; Andrew Reeve, GB-Romsey; Changpeng Fan, DE-Berlin

In a Quality of Service (QoS) routed network each traffic engineering class (TE class) using a link has a different allocation of bandwidth. If this bandwidth fills up, the nodes in the network have to be notified because the link will soon be unable to admit calls of that TE class. Up to now this notification is done via link state updates triggered by thresholds or timers.

It is hereby proposed to use one of the unused bits in the packets that flow through the nodes. If one of the nodes detects a bandwidth pool filling up, it sets this bit to indicate that the bandwidth pool is almost full. The packet is then routed to its destination normally. When the destination detects the set bit, it then sets the links used by that tunnel to "full state". When the destination receives a packet with a "bandwidth pool full" bit which is not set, the links are set to "free state" again. The nodes should use thresholds and dampening for changing the state of the links to avoid unnecessary oscillating. This method provides a more exact and up-to-date picture of the network and its actual load.

The bit used can for example be one of the reserved bits in the packet header, such as the ECN (Explicit Congestion Notification) bits in the IP (Internet Protocol) header or one of the bits in the IPv6 flow label.

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