On Packet Aggregation and Header Compression Mechanisms for Improving VoIP Quality in Mesh Networks

Abstract

An improved aggregation scheme for wireless multi-hop mesh networks is disclosed. An aggregator at each node operates to merge VoIP packets at an ingress/source node with a forced delay, but at an intermediate node aggregated packets are either sent directly to their destination or to the next hop without deaggregation. A novel compression mechanism for compressing and decompressing the aggregated packets is also disclosed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an exemplary wireless mesh network;

FIG. 2 is a schematic of an illustrative node in the mesh network of FIG. 1;

FIG. 3 is a schematic of an illustrative router architecture and aggregator at a node;

FIG. 4 is a schematic of a plurality of nodes for describing an example of accretion aggregation of packets in accordance with an aspect of the invention;

FIG. 5 is a flow diagram of an accretion aggregation methodology in accordance with an aspect of the invention;

FIG. 6 is a schematic of an illustrative methodology for zero-length header compression (ZLHC) in accordance with an aspect of the invention;

FIG. 7 is a schematic of ZLHC in a mesh network using hop-by-hop aggregation; and

FIG. 8 is a schematic of ZLHC in a mesh network using accretion aggregation.

Claims

1. In a mesh network comprising a plurality of nodes, each node having a client interface and a backhaul interface for communicating between the nodes, a method for aggregating a plurality of packets, comprising: at an ingress node that receives packets from at least one client, introducing a forced delay prior to aggregating packets at the ingress node;at least one intermediate node communicating with the ingress node, forwarding aggregated packets received from the ingress node to a destination node.

2. The method of claim 1, further comprising the step of setting a minimum number of packets to be aggregated at the ingress node.

3. The method of claim 2, further comprising the step of setting a timer specifying a maximum time to wait to aggregate the packets at the ingress node.

4. The method of claim 3, further comprising upon expiration of the timer, aggregating packets from all flows to the ingress node having the same destination node until a size of the aggregated packets reaches the maximum transmission unit (MTU), and then sending the aggregated packets to the destination node via the at least one intermediate node.

5. The method of claim 3, further comprising upon expiration of the timer, aggregating packets from all flows to the ingress node having a same next hop intermediate node until a size of the aggregated packets reaches the maximum transmission unit (MTU), and then sending the aggregated packets to the next hop intermediate node.

6. In a mesh network comprising a plurality of nodes, each node having a client interface and a backhaul interface for communicating between the nodes, and a machine readable medium containing machine readable instructions which, when executed by a processor, enable: an ingress node that receives packets from at least one client to introduce a forced delay prior to aggregating packets at the ingress node; andat least one intermediate node communicating with the ingress node to forward aggregated packets received from the ingress node to a destination node.

7. The nodes of claim 6, wherein a minimum number of packets are to be aggregated at the ingress node.

8. The nodes of claim 7, wherein a maximum time to wait to aggregate the packets is set at the ingress node.

9. The nodes of claim 8, wherein the machine readable medium containing machine readable instructions which, when executed by the processor, upon expiration of the timer, enable the ingress node to aggregate packets from all flows to the ingress node having the same destination node until a size of the aggregated packets reaches the maximum transmission unit (MTU), and then send the aggregated packets to the destination node via the at least one intermediate node.

10. The nodes of claim 8, wherein the machine readable medium containing machine readable instructions which, when executed by the processor, upon expiration of the timer, enable the ingress node to aggregate packets from all flows to the ingress node having a same next hop intermediate node until a size of the aggregated packets reaches the maximum transmission unit (MTU), and then send the aggregated packets to the next hop intermediate node.

11. A method for compressing and decompressing packet headers of a plurality of packets in a mesh network including a plurality of nodes, comprising: aggregating a plurality of packets in a flow into aggregated packets at a first node in the mesh network;extracting the uncompressed header of a first packet in the flow;compressing the aggregated packets at the first node;deaggregating the aggregated packets at a second node in the mesh network; anddecompressing the aggregated packets with the uncompressed header of the first packet in the flow at a second node in the mesh network.