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+.. _span_doc:
+
+Switched Port Analyzer
+======================
+
+This is a memo intended to contain documentation of the VPP SPAN
+implementation. Everything that is not directly obvious should come
+here.
+
+Port mirroring is used on a network switch to send a copy of network
+packets seen on one switch port to a network monitoring connection on
+another switch port. Can be used by network engineers or administrators
+to measure performance, analyze and debug data or diagnose errors on a
+network.
+
+RX traffic node
+~~~~~~~~~~~~~~~
+
+There is one static node to mirror incoming packets. \* span-input:
+Creates a copy of incoming buffer due to incoming buffers can be reused
+internally.
+
+Chaining: dpdk-input -> span-input -> \* original buffer is sent to
+ethernet-input for processing \* buffer copy is sent to interface-output
+
+Configuration
+~~~~~~~~~~~~~
+
+SPAN supports the following CLI configuration commands:
+
+Enable/Disable SPAN (CLI)
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+::
+
+   set interface span <if-name> [disable | destination <if-name>]
+
+: mirrored interface name destination : monitoring interface name
+disable: delete mirroring
+
+Enable/Disable SPAN (API)
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+SPAN supports the following API configuration command:
+sw_interface_span_enable_disable src GigabitEthernet0/8/0 dst
+GigabitEthernet0/9/0 sw_interface_span_enable_disable src_sw_if_index 1
+dst_sw_if_index 2
+
+src/src_sw_if_index: mirrored interface name dst/dst_sw_if_index:
+monitoring interface name
+
+Remove SPAN entry (API)
+^^^^^^^^^^^^^^^^^^^^^^^
+
+SPAN supports the following API configuration command:
+sw_interface_span_enable_disable src_sw_if_index 1 dst_sw_if_index 2
+disable
+
+src_sw_if_index: mirrored interface name dst_sw_if_index: monitoring
+interface name
+
+Configuration example
+~~~~~~~~~~~~~~~~~~~~~
+
+Mirror all packets on interface GigabitEthernet0/10/0 to interface
+GigabitEthernet0/11/0.
+
+Configure IPv4 addresses on mirrored interface: set interface ip address
+GigabitEthernet0/10/0 192.168.1.13/24 set interface state
+GigabitEthernet0/10/0 up
+
+Configure IPv4 addresses on monitoring interface: set interface ip
+address GigabitEthernet0/11/0 192.168.2.13/24 set interface state
+GigabitEthernet0/11/0 up
+
+Configure SPAN set span src GigabitEthernet0/10/0 dst
+GigabitEthernet0/11/0
+
+Operational data
+~~~~~~~~~~~~~~~~
+
+Active SPAN mirroring CLI show command: show interfaces span
+
+Active SPAN mirroring API dump command: sw_interface_span_dump