公开(公告)号：US09792106B1

公开(公告)日：2017-10-17

申请号：US14450935

申请日：2014-08-04

Applicant: Cisco Technology, Inc.

Inventor： Raja Kommula ,  Chickayya Naik ,  Naren Mididaddi ,  Francesco Meo ,  Sharanya Subramanian

IPC: G06F9/445 ,  G06F1/24 ,  G06F9/44 ,  H04L12/24

CPC classification number: G06F8/65 ,  G06F1/24 ,  G06F8/656 ,  G06F9/4406 ,  H04L41/082 ,  H04L43/10

Abstract: A network device includes a control processor and a network processor unit (NPU) to forward network packets between network ports of the device. The processor downloads a new operating system (OS). The processor performs a fast upgrade to the new OS using a fast upgrade/reload technique to isolate the processor from interruptions and, without rebooting the processor, start the new OS in place of an existing OS. The fast upgrade/reload also includes delaying a reset of the NPU so that the NPU continues to route the network packets based on existing forwarding information. The fast upgrade/reload includes resetting the NPU only when the new OS first accesses the NPU, and then programming the reset NPU.