Cisco Cisco Nexus 5010 Switch Libro bianco

Page 10 of 11

--------------------------------------------------------------------------------

1 sec | 5 sec | 1 min | 5 min | 1 hour |

--------------------------------------------------------------------------------

0.0| 8.0| 3.2| 0.0|19.2| 7.4| 0.0|22.4| 6.6| 0.0|25.6| 7.5| 0.0|25.6| 7.1|

0.0|14.4| 4.4| 0.0|24.0| 9.3| 0.0|22.4| 7.7| 0.0|25.6| 7.7| N/A |

0.0|12.8| 6.4| 0.0|24.0| 8.6| 0.0|22.4| 6.7| 0.0|25.6| 7.7| N/A |

0.0|16.0| 7.6| 0.0|19.2| 7.1| 0.0|24.0| 8.1| 0.0|27.2| 7.3| N/A |

4.8|19.2| 12.4| 0.0|19.2| 6.4| 0.0|24.0| 6.7| 0.0|25.6| 7.8| N/A |

N/A | 0.0|19.2| 6.1| N/A | 0.0|25.6| 7.6| N/A |

N/A | 0.0|19.2| 6.3| N/A | 0.0|25.6| 6.7| N/A |

N/A | 0.0|20.8| 5.1| N/A | 0.0|24.0| 6.4| N/A |

N/A | 0.0|17.6| 5.8| N/A | 0.0|22.4| 6.3| N/A |

N/A | 0.0|20.8| 7.4| N/A | 0.0|22.4| 6.9| N/A |

N/A | 0.0|20.8| 6.6| N/A | 0.0|24.0| 6.4| N/A |

N/A | 1.6|20.8| 7.1| N/A | 0.0|22.4| 6.6| N/A |

--------------------------------------------------------------------------------

The output displays the buffer usage histogram as a table. The first line shows which interface buffer utilization

histogram is displayed. The second line specifies the sampling mode. The first example is obtained for slow

sampling mode and the second example is for fast sampling mode. The buffer utilization histogram states are

divided into three sections. The first table displays ingress buffer utilization histogram data. The second displays

egress unicast data. The last table belongs to the egress multicast buffer usage histogram.

Each ingress and egress table is divided by time periods from one second to one hour. For each time period, three

columns are presented. The first column for each time period shows a minimum value of buffer usage. The second

column shows maximum values. The third column shows average usage of buffer over time. All values are

measured in kilobytes (KB).

For the one-second column, the system generates values by pooling samples every 250 milliseconds or one

second, depending on the sampling period. Five samples from the one-second column make the first entry in the

five-second column. Twelve samples from the five-second column make up the first entry in the one-minute

column. Five samples from the one-minute column create the first entry in the five-minute column. Twelve samples

from the five-minute column create the first entry in the one-hour column. All information is copied to a
“buffer_util_stats” file every hour.

Conclusion

The Buffer Utilization Histogram feature on Cisco Nexus 5600 and Nexus 6000 switches reveals real-time buffer

usage per port. The switches can obtain histograms of per-

port buffer usage for up to an hour’s duration. After an

hour all data are saved in the switch memory. Furthermore, the states can be extracted into an XML file. All of

these benefits give network administrators a comprehensive view of buffer usage in a particular network.

Administrators can use this functionality to correlate latency in the network and buffer usage as a means of

discovering traffic microbursts in the network.