Introduction
This document describes how to configure a remote switched port
analyzer (RSPAN) session on a Nexus 7000 Series Switch that monitors the
traffic between Ethernet ports on two different Nexus 7000 Series
Switches.
Prerequisites
Requirements
Ensure that you meet these requirements before you attempt this
configuration:
Components Used
The information in this document is based on Nexus 7000 Series NX-OS
devices.
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
Conventions
Refer to the Cisco Technical Tips
Conventions for more information on document conventions.
Background Information
You can use switched port analyzer (SPAN) in order to analyze network
traffic that passes through ports or VLANs of the switch, which send a copy of
the traffic to a destination port where the network analyzer connects to the
switch.
In order to extend SPAN, RSPAN enables remote monitoring of multiple
switches across your network. The Nexus 7000 Series Switch is limited in what
it can do with RSPAN. An RSPAN VLAN cannot be used as a SPAN destination.
Therefore, the Nexus 7000 switch can only use RSPAN as a transit VLAN or a
source VLAN and pull data from the RSPAN VLAN. You cannot place anything into
the RSPAN VLAN from the Nexus 7000 switch.
Configure
This configuration example uses source ports on two different Nexus
7000 series switches and a destination port on one Nexus 7000 switch where the
network analyzer has connected. Separate Ethernet 1/1 links are set up between
the two devices: one link as a span destination and the other link as access to
the RSPAN VLAN.
Note: Use the
Command
Lookup Tool
(registered customers only)
to obtain more information on the commands used in this
section.
Network Diagram
This document uses this network setup:
This example uses the ports listed in this table:
Device
|
Source Port
|
Destination Port
|
Nexus 1 |
Ethernet 2/15 and 2/16 |
Ethernet 1/1 |
Nexus 2 |
Ethernet 1/1, 2/26 to 2/28 |
Ethernet 2/37 to 2/40 |
From the Nexus 1 switch, the SPAN traffic from the source is carried to
the destination port and copied onto the RSPAN VLAN. The traffic is then
forwarded over the link to the Nexus 2 switch on the Ethernet 1/1 interface.
Next, RSPAN VLAN traffic is sent to the destination port where the device, such
as a SwitchProbe device or other Remote Monitoring (RMON) probe or security
device, can receive and analyze the packets.
Configurations
This document uses these configurations:
Nexus 1 |
Nexus1#configure terminal
!--- Configure the interface VLAN 15 as RSPAN VLAN.
Nexus1(config)#vlan 15
Nexus1(config-vlan)#remote-span
Nexus1(config-vlan)#exit
!--- Configure the switchport interface as a SPAN destination.
Nexus1(config)#interface ethernet 1/1
Nexus1(config-if)#switchport monitor
Nexus1(config-if)#no shutdown
Nexus1(config-if)#exit
!--- Configure the SPAN session.
Nexus1(config)#monitor session 1
!---Configure the source port.
Nexus1(config-monitor)#source interface ethernet 2/15-16
!--- Configure the destination port.
Nexus1(config-monitor)#destination interface ethernet 1/1
!--- Enable the SPAN session (by default the session is in shutdown state).
Nexus1(config-monitor)#no shut
Nexus1(config-monitor)#exit
|
Nexus 2 |
Nexus2#configure terminal
!--- Configuration of interface VLAN 15 as RSPAN VLAN.
Nexus2(config)#vlan 15
Nexus2(config-vlan)#remote-span
Nexus2(config-vlan)#exit
!--- Configure the switchport interface to access in RSPAN VLAN.
Nexus2(config)#interface ethernet 1/1
Nexus2(config-if)#switchport mode access
Nexus2(config-if)#switchport access vlan 15
Nexus2(config-if)#no shutdown
Nexus2(config-if)#exit
!--- Configure the switchport interfaces as a SPAN destination.
Nexus2(config)#interface ethernet 2/37-40
Nexus2(config-if)#switchport monitor
Nexus2(config-if)#exit
!--- Configure the SPAN session.
Nexus2(config)#monitor session 1
!--- Configure the source port.
Nexus2(config-monitor)#source interface ethernet 2/26-28
Nexus2(config-monitor)#source vlan 15
!--- Configure the destination port.
Nexus2(config-monitor)#destination interface ethernet 2/37-40
!--- Enable the SPAN session (by default the session is in shutdown state).
Nexus2(config-monitor)#no shut
Nexus2(config-monitor)#exit
|
Verify
Use this section to confirm that your configuration works
properly.
The
Output Interpreter Tool
(registered customers only)
(OIT) supports certain
show commands. Use the OIT to view an analysis of
show command output.
Here are some of the SPAN and RSPAN verification commands:
Nexus 1:
-
Use the
show
monitor
command in order to display the status of the
RSPAN sessions.
Nexus1# show monitor
Session State Reason Description
------- ----------- ---------------------- --------------------------------
1 up The session is up
-
Use the
show
monitor session [session
session_number]
command in order to display
the ERSPAN session configuration.
Nexus1# show monitor session 1
session 1
---------------
type : local
state : up
source intf :
rx : Eth1/15 Eth1/16
tx : Eth1/15 Eth1/16
both : Eth1/15 Eth1/16
source VLANs :
rx :
tx :
both :
filter VLANs : filter not specified
destination ports : Eth1/1
Legend: f = forwarding enabled, l = learning enabled
-
Use the
show
monitor session all
command in order to display all ERSPAN
sessions configuration in the device.
Nexus 2:
Related Information