Белая книга для Cisco Cisco Nexus 5010 Switch

 

 

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What You Will Learn 

This document provides an overview of the microburst monitoring feature on the Cisco Nexus

®

 5600 platform and 

Cisco Nexus 6000 Series Switches. With the proliferation of virtual machines in the data center, the likelihood that 

multiple devices will send traffic to the same destination increases dramatically. Because Ethernet is a serial 

transport medium, these burst events cause temporary congestion that can go undetected. This microburst 

congestion can lead to buffer exhaustion, which results in tail drops and lost packets. The Cisco Nexus 5600 

platform and Cisco Nexus 6000 Series Switches introduce a way to mark microbursts so that they can be 

observed, tracked, and understood so that effective mitigation actions can be implemented. 

Introduction 

A microburst is a short burst of traffic with a duration tending toward zero and an intensity tending toward infinite. 

Microbursts usually lead to temporary traffic buffering, increasing latency momentary, and can cause traffic drops if 

the buffering capacity is exceeded. Microbursts in typical data center networks are actually very common, but they 

are often undetected. Numerous virtual machines, physical machines, and data storage devices communicate at 

the same time, which leads to intense traffic for extremely short periods of time, or microbursts. It is hard to predict 

where microbursts will occur and how traffic on a particular device will be affected. 

Common data center switches provide basic per-port bandwidth monitoring and can show the current bandwidth on 

a port. However, these measurement tools are unable to detect microbursts because they are monitoring very 

large time intervals. 

The solution is a feature that can detect unexpected bursts of data in extremely short periods of time, on the order 

of microseconds. The Cisco Nexus 5600 platform and Cisco Nexus 6000 Series Switches support a microburst 

monitoring feature that detects microbursts that occur in microsecond time periods. 

Microbursts 

A microburst is very intense traffic in a very short period of time. Microbursts in a network most commonly occur at 

the moment when two or more devices send traffic to the same destination. For example, in Figure 1 two servers 

are sending traffic to the same destination and causing a microburst at the egress port on the switch.