Cisco Cisco Nexus 5010 Switch Libro bianco

 

 

© 2014 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. 

Page 1 of 4 

White Paper 

SPAN-on-Drop Feature on Cisco Nexus Switches: 
Troubleshoot Network Congestion 

Introduction 

Congestion in networks happens more often than expected. Identifying which application or flow is experiencing 

congestion can be difficult. 

The new Cisco

®

 SPAN-on-Drop feature in the Cisco Nexus

®

 5600 switches allows the user to identify the 

applications experiencing congestion in the network and correlate packet drop with applications. 

Note:   Everything discussed in this document paper applies to both the Cisco Nexus 5600 platform and Cisco 
Nexus 6000 Series of Switches. 

SPAN-on-Drop enables the Cisco Switched Port Analyzer (SPAN) feature to be applied to packets that would 

normally be dropped due to lack of available buffer or queue space on ingress. With SPAN-on-Drop, instead of 

dropping a packet when congestion occurs, the system stores the packet in a separate SPAN-on-Drop buffer and 

then sends the packet to the specified SPAN-on-Drop destination port. SPAN-on-Drop with Encapsulated Remote 

SPAN (ERSPAN) is an extension of this feature in which the dropped frames are spanned and sent to a remote IP 

address instead of a local port. 

Line-Rate SPAN 

The Cisco Nexus 5600 platform supports high-performance SPAN.  

Figure 1 shows the use of line-rate SPAN in this switch. 

Figure 1.    Line-Rate SPAN