X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Ftap.rst;h=f3ee95d2897bbb7536547ea3e337a8af70489da6;hb=5d5aeeedab696b6dc25ce0674d07d7f5b84d2d36;hp=4986e47e9f5756a6478bdbfbe8adc3d7761f82b8;hpb=de96fe68ae95990f5ce2cd4c8d9547ab62d2a810;p=dpdk.git

diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
index 4986e47e9f..f3ee95d289 100644
--- a/doc/guides/nics/tap.rst
+++ b/doc/guides/nics/tap.rst
@@ -46,7 +46,7 @@ These TAP interfaces can be used with Wireshark or tcpdump or Pktgen-DPDK
 along with being able to be used as a network connection to the DPDK
 application. The method enable one or more interfaces is to use the
 ``--vdev=net_tap0`` option on the DPDK application command line. Each
-``--vdev=net_tap1`` option give will create an interface named dtap0, dtap1,
+``--vdev=net_tap1`` option given will create an interface named dtap0, dtap1,
 and so on.
 
 The interface name can be changed by adding the ``iface=foo0``, for example::
@@ -58,6 +58,33 @@ needed, but the interface does not enforce that speed, for example::
 
    --vdev=net_tap0,iface=foo0,speed=25000
 
+Normally the PMD will generate a random MAC address, but when testing or with
+a static configuration the developer may need a fixed MAC address style.
+Using the option ``mac=fixed`` you can create a fixed known MAC address::
+
+   --vdev=net_tap0,mac=fixed
+
+The MAC address will have a fixed value with the last octet incrementing by one
+for each interface string containing ``mac=fixed``. The MAC address is formatted
+as 00:'d':'t':'a':'p':[00-FF]. Convert the characters to hex and you get the
+actual MAC address: ``00:64:74:61:70:[00-FF]``.
+
+It is possible to specify a remote netdevice to capture packets from by adding
+``remote=foo1``, for example::
+
+   --vdev=net_tap,iface=tap0,remote=foo1
+
+If a ``remote`` is set, the tap MAC address will be set to match the remote one
+just after netdevice creation. Using TC rules, traffic from the remote netdevice
+will be redirected to the tap. If the tap is in promiscuous mode, then all
+packets will be redirected. In allmulti mode, all multicast packets will be
+redirected.
+
+Using the remote feature is especially useful for capturing traffic from a
+netdevice that has no support in the DPDK. It is possible to add explicit
+rte_flow rules on the tap PMD to capture specific traffic (see next section for
+examples).
+
 After the DPDK application is started you can send and receive packets on the
 interface using the standard rx_burst/tx_burst APIs in DPDK. From the host
 point of view you can use any host tool like tcpdump, Wireshark, ping, Pktgen