- Overview
- Tools Used in Troubleshooting
- Installation
- Upgrade
- Licenses
- High Availability
- VSM and VEM Modules
- Ports
- Port Profiles
- Port Channels and Trunking
- Layer 2 Switching
- VLANs
- Private VLANs
- NetFlow
- Access Control Lists
- Quality of Service
- SPAN
- Multicast IGMP Snooping
- DHCP, DAI, and IPSG
- System
- Network Segmentation Manager
- Ethanalyzer
- Before Contacting Technical Support
Cisco Nexus 1000V for Microsoft Hyper-V Troubleshooting Guide, Release 5.2(1)SM3(1.1)
- Updated:
- December 19, 2014
Chapter: SPAN
SPAN
This chapter describes how to identify and resolve problems that relate to SPAN.
Information About SPAN
The Switched Port Analyzer (SPAN) feature (sometimes called port mirroring or port monitoring) selects network traffic for analysis by a network analyzer. The network analyzer can be a Cisco SwitchProbe or other Remote Monitoring (RMON) probe.
The Cisco Nexus 1000V supports two types of SPAN:
- SPAN (local SPAN) that can monitor sources within a host or Virtual Ethernet Module (VEM).
- Encapsulated remote SPAN (ERSPAN) that can send monitored traffic to an IP destination.
For detailed information about how to configure local SPAN or ERSPAN, see the Cisco Nexus 1000V for Microsoft Hyper-V System Management Configuration Guide.
SPAN Session Guidelines
The following are SPAN session guidelines:
- When a SPAN session contains multiple transmit source ports, packets that these ports receive might be replicated even though they are not transmitted on the ports. Examples include the following:
–
Traffic that results from flooding
– Broadcast and multicast traffic
- For VLAN SPAN sessions with both receive and transmit configured, two packets (one from receive and one from transmit) are forwarded from the destination port if the packets get switched on the same VLAN.
- After a live migration ( a live migration provides the capability to move a virtual machine (VM) from one node in a Microsoft Windows server failover cluster to another node without a perceived interruption in service by applications/clients connecting to the VM), the following might occur:
– A session is stopped if the source and destination ports are separated.
– A session resumes if the source and destination ports end up on the same host.
– The limit of 64 SPAN sessions is not exceeded.
– At least one operational source is configured.
– At least one operational destination is configured.
– The configured source and destination are on the same host.
– The session is enabled with the no shut command.
– All the source ports go down or are removed.
– All the destination ports go down or are removed.
– All the source and destination ports are separated by a live migration.
Problems with SPAN
SPAN Troubleshooting Commands
You can use the commands in this section to troubleshoot problems related to SPAN.
|
|
|
|---|---|
|
|
|
Displays the current state of a SPAN session, the reason it is down, and the session configuration. |
|
Example 17-1 show monitor command
Example 17-2 show monitor session command
Example 17-3 module vem execute vemcmd show span command
Feedback