Checksumming encapsulated network packets

摘要

Methods and apparatus for checksumming network packets encapsulated according to an encapsulation protocol are described in which a single checksum is performed at the encapsulation layer, with checksum generation performed at the source encapsulation layer and checksum validation performed at the destination encapsulation layer. The packet source and packet destination may be informed by the encapsulation layer that a checksum operation is not necessary for the network packets. By performing checksumming at the encapsulation layer, the method may reduce overhead as checksum computation is initiated once rather than twice as in conventional encapsulation techniques. In addition, checksum algorithms may be used that provide stronger error detection or correction than is provided by standard network protocol checksumming, different checksum algorithms may be selected for different paths according to one or more criteria, and checksum operations may be offloaded to hardware.

主权项

1. A provider network, comprising;
a network substrate; and a plurality of host devices coupled to the network substrate, wherein each host device includes a plurality of virtual machines (VMs) and a virtual machine monitor (VMM) that monitors the plurality of VMs on the respective host device, wherein each VMM is configured to:
obtain one or more Internet Protocol (IP) packets generated by a source VM on the respective host device, wherein the one or more IP packets are not checksummed by the source VM;encapsulate the one or more IP packets according to an encapsulation protocol to generate a network substrate packet that includes the one or more IP packets as a payload, wherein the network substrate packet includes network substrate packet metadata;generate a checksum of at least the payload of the network substrate packet according to a checksum algorithm;write the generated checksum to a checksum field of the network substrate packet metadata; andsend the network substrate packet to a destination on the provider network over the network substrate.