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authorjdenisco <jdenisco@cisco.com>2019-07-30 08:54:01 -0400
committerDave Barach <openvpp@barachs.net>2019-08-08 22:57:31 +0000
commitc54235776c08ec1e10d80d8c91e6e45e2d2f6831 (patch)
tree0cebf2921cb8e47aedcf815d6177e670c2244355
parent9cbf6818b37275199b6c0ebef0ef3d8ecaac0a3b (diff)
docs: Add Ray's ACL use case
Change-Id: Id99f16953a23a4be4cc1fb94419ea8282fa720e8 Signed-off-by: jdenisco <jdenisco@cisco.com>
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+.. _aclwithvpp:
+
+Access Control Lists (ACLs) with FD.io VPP
+==========================================
+
+This section is overview of the options available to implement ACLs in
+FD.io VPP. As there are a number of way's to address ACL-like functionality,
+it is worth a separate survey of these options with some commentary on
+features and performance
+
+All performance numbers and examples from this document are reused from
+the `FD.io CSIT v19.04 performance report <https://docs.fd.io/csit/rls1904/report/>`__
+All information and performance is accurate for
+`FD.io VPP 19.04 <https://git.fd.io/vpp/tag/?h=v19.04>`__ release. The
+sections *performance* & *operational data* below correlate directly with
+those sections from the FD.io CSIT performance report.
+
+Summary
+-------
+
++---------------------+-----------+-----------------------------------+
+| Option | Relative | Features & Notes |
+| | Performan | |
+| | ce | |
++=====================+===========+===================================+
+| :ref:`aclplugin` | Lowest | Match on restricted L2-L4 fields, |
+| | | stateful & stateless |
++---------------------+-----------+-----------------------------------+
+| :ref:`vppcop` | Highest | Match on Layer 3 IPs, stateless |
+| | (software | |
+| | only) | |
++---------------------+-----------+-----------------------------------+
+| :ref:`vppflow` | Highest | Match on restricted L2-L4 fields, |
+| | (accelera | stateless, limited number of |
+| | ted) | flows |
++---------------------+-----------+-----------------------------------+
+| :ref:`classifiers` | TBD | Match on any field in the first |
+| | | 80 bytes, Not measured |
++---------------------+-----------+-----------------------------------+
+
+FD.io VPP ACL Options
+---------------------
+
+.. _aclplugin:
+
+The FD.io VPP ACL Plugin
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The plugin was originally developed as part of FD.io VPP and OpenStack
+integration. The plugin needs to be enabled on specific interfaces.
+
+Supports stateful and stateless ACLs on …
+""""""""""""""""""""""""""""""""""""""""""
+
+- MACs
+- IPS
+- UDP Ports
+- TCP Ports & Flags
+- ICMP Messages
+
+Directional
+"""""""""""
+
+* Input ACLs
+
+ * Run before the IP flow classification.
+
+* ACLs
+
+ * Run before interface output.
+
+Actions
+"""""""
+- Permit (sl)
+- Drop (sf)
+- Permit+Reflect (sf)
+
+Stateful (sf)
+"""""""""""""
+
+- Actions: permit+reflect
+- Most heavily optimized, as are the most common use case.
+- Faster because stateful uses a flow cache, it means the ACL hit is only taken once, up front for the flow and then becomes just look-up.
+- Uses more memory, less deterministic as the flow cache makes it
+ more susceptible to the effects of the memory hierarchy and
+ locality.
+
+Stateless (sl)
+""""""""""""""
+
+- Actions : permit, drop
+- Less optimized, less common use case.
+- Slower as there is no flow-cache, every new packet incurs the same
+ amount ACL processing.
+- Uses less memory, and are more deterministic (compared to
+ stateful).
+
+Operational Data
+----------------
+
+Input/Stateless
+~~~~~~~~~~~~~~~
+
+Test Case: 10ge2p1x520-ethip4udp-ip4base-iacl1sl-10kflows-ndrpdr
+""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+.. code-block:: console
+
+ DUT1:
+ Thread 0 vpp_main (lcore 1)
+ Time 3.8, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ acl-plugin-fa-cleaner-process any wait 0 0 14 1.29e3 0.00
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 7 0 0 9.18e2 0.00
+ api-rx-from-ring active 0 0 52 8.96e4 0.00
+ dpdk-process any wait 0 0 1 1.35e4 0.00
+ fib-walk any wait 0 0 2 2.69e3 0.00
+ ip6-icmp-neighbor-discovery-ev any wait 0 0 4 1.32e3 0.00
+ lisp-retry-service any wait 0 0 2 2.90e3 0.00
+ unix-epoll-input polling 7037 0 0 1.25e6 0.00
+ vpe-oam-process any wait 0 0 2 2.28e3 0.00
+
+ Thread 1 vpp_wk_0 (lcore 2)
+ Time 3.8, average vectors/node 249.02, last 128 main loops 32.00 per node 273.07
+ vector rates in 6.1118e6, out 6.1118e6, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ TenGigabitEtherneta/0/0-output active 47106 11721472 0 9.47e0 248.83
+ TenGigabitEtherneta/0/0-tx active 47106 11721472 0 4.22e1 248.83
+ TenGigabitEtherneta/0/1-output active 47106 11721472 0 1.02e1 248.83
+ TenGigabitEtherneta/0/1-tx active 47106 11721472 0 4.18e1 248.83
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 7 0 0 1.39e3 0.00
+ acl-plugin-in-ip4-fa active 94107 23442944 0 1.75e2 249.11
+ dpdk-input polling 47106 23442944 0 4.64e1 497.66
+ ethernet-input active 94212 23442944 0 1.55e1 248.83
+ ip4-input-no-checksum active 94107 23442944 0 3.23e1 249.11
+ ip4-lookup active 94107 23442944 0 2.91e1 249.11
+ ip4-rewrite active 94107 23442944 0 2.48e1 249.11
+ unix-epoll-input polling 46 0 0 1.54e3 0.00
+
+Input/Stateful
+~~~~~~~~~~~~~~
+
+Test Case: 64b-1t1c-ethip4udp-ip4base-iacl1sf-10kflows-ndrpdr
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+.. code-block:: console
+
+ DUT1:
+ Thread 0 vpp_main (lcore 1)
+ Time 3.9, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ acl-plugin-fa-cleaner-process any wait 0 0 16 1.40e3 0.00
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 8 0 0 8.97e2 0.00
+ api-rx-from-ring active 0 0 52 7.12e4 0.00
+ dpdk-process any wait 0 0 1 1.69e4 0.00
+ fib-walk any wait 0 0 2 2.55e3 0.00
+ ip4-reassembly-expire-walk any wait 0 0 1 1.27e4 0.00
+ ip6-icmp-neighbor-discovery-ev any wait 0 0 4 1.09e3 0.00
+ ip6-reassembly-expire-walk any wait 0 0 1 2.57e3 0.00
+ lisp-retry-service any wait 0 0 2 1.18e4 0.00
+ statseg-collector-process time wait 0 0 1 6.38e3 0.00
+ unix-epoll-input polling 6320 0 0 1.41e6 0.00
+ vpe-oam-process any wait 0 0 2 7.53e3 0.00
+
+ Thread 1 vpp_wk_0 (lcore 2)
+ Time 3.9, average vectors/node 252.74, last 128 main loops 32.00 per node 273.07
+ vector rates in 7.5833e6, out 7.5833e6, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ TenGigabitEtherneta/0/0-output active 58325 14738944 0 9.41e0 252.70
+ TenGigabitEtherneta/0/0-tx active 58325 14738944 0 4.32e1 252.70
+ TenGigabitEtherneta/0/1-output active 58323 14738944 0 1.02e1 252.71
+ TenGigabitEtherneta/0/1-tx active 58323 14738944 0 4.31e1 252.71
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 8 0 0 1.62e3 0.00
+ acl-plugin-in-ip4-fa active 116628 29477888 0 1.01e2 252.75
+ dpdk-input polling 58325 29477888 0 4.63e1 505.41
+ ethernet-input active 116648 29477888 0 1.53e1 252.71
+ ip4-input-no-checksum active 116628 29477888 0 3.21e1 252.75
+ ip4-lookup active 116628 29477888 0 2.90e1 252.75
+ ip4-rewrite active 116628 29477888 0 2.48e1 252.75
+ unix-epoll-input polling 57 0 0 2.39e3 0.00
+
+Output/Stateless
+~~~~~~~~~~~~~~~~
+
+Test Case: 64b-1t1c-ethip4udp-ip4base-oacl10sl-10kflows-ndrpdr
+""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+ .. code-block:: console
+
+ DUT1:
+ Thread 0 vpp_main (lcore 1)
+ Time 3.8, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ acl-plugin-fa-cleaner-process any wait 0 0 14 1.43e3 0.00
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 7 0 0 9.23e2 0.00
+ api-rx-from-ring active 0 0 52 8.01e4 0.00
+ dpdk-process any wait 0 0 1 1.59e6 0.00
+ fib-walk any wait 0 0 2 6.81e3 0.00
+ ip6-icmp-neighbor-discovery-ev any wait 0 0 4 2.81e3 0.00
+ lisp-retry-service any wait 0 0 2 3.64e3 0.00
+ unix-epoll-input polling 4842 0 0 1.81e6 0.00
+ vpe-oam-process any wait 0 0 1 2.24e4 0.00
+
+ Thread 1 vpp_wk_0 (lcore 2)
+ Time 3.8, average vectors/node 249.29, last 128 main loops 36.00 per node 271.06
+ vector rates in 5.9196e6, out 5.9196e6, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ TenGigabitEtherneta/0/0-output active 45595 11363584 0 9.22e0 249.23
+ TenGigabitEtherneta/0/0-tx active 45595 11363584 0 4.25e1 249.23
+ TenGigabitEtherneta/0/1-output active 45594 11363584 0 9.75e0 249.23
+ TenGigabitEtherneta/0/1-tx active 45594 11363584 0 4.21e1 249.23
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 7 0 0 1.28e3 0.00
+ acl-plugin-out-ip4-fa active 91155 22727168 0 1.78e2 249.32
+ dpdk-input polling 45595 22727168 0 4.64e1 498.46
+ ethernet-input active 91189 22727168 0 1.56e1 249.23
+ interface-output active 91155 22727168 0 1.13e1 249.32
+ ip4-input-no-checksum active 91155 22727168 0 1.95e1 249.32
+ ip4-lookup active 91155 22727168 0 2.88e1 249.32
+ ip4-rewrite active 91155 22727168 0 3.53e1 249.32
+ unix-epoll-input polling 44 0 0 1.53e3 0.00
+
+Output/Stateful
+~~~~~~~~~~~~~~~
+
+Test Case: 64b-1t1c-ethip4udp-ip4base-oacl10sf-10kflows-ndrpdr
+""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+.. code-block:: console
+
+ DUT1:
+ Thread 0 vpp_main (lcore 1)
+ Time 3.8, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ acl-plugin-fa-cleaner-process any wait 0 0 16 1.47e3 0.00
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 8 0 0 8.51e2 0.00
+ api-rx-from-ring active 0 0 50 7.24e4 0.00
+ dpdk-process any wait 0 0 2 1.93e4 0.00
+ fib-walk any wait 0 0 2 2.02e3 0.00
+ ip4-reassembly-expire-walk any wait 0 0 1 3.96e3 0.00
+ ip6-icmp-neighbor-discovery-ev any wait 0 0 4 9.84e2 0.00
+ ip6-reassembly-expire-walk any wait 0 0 1 3.76e3 0.00
+ lisp-retry-service any wait 0 0 2 1.49e4 0.00
+ statseg-collector-process time wait 0 0 1 4.98e3 0.00
+ unix-epoll-input polling 5653 0 0 1.55e6 0.00
+ vpe-oam-process any wait 0 0 2 1.90e3 0.00
+
+ Thread 1 vpp_wk_0 (lcore 2)
+ Time 3.8, average vectors/node 250.85, last 128 main loops 36.00 per node 271.06
+ vector rates in 7.2686e6, out 7.2686e6, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ TenGigabitEtherneta/0/0-output active 55639 13930752 0 9.33e0 250.38
+ TenGigabitEtherneta/0/0-tx active 55639 13930752 0 4.27e1 250.38
+ TenGigabitEtherneta/0/1-output active 55636 13930758 0 9.81e0 250.39
+ TenGigabitEtherneta/0/1-tx active 55636 13930758 0 4.33e1 250.39
+ acl-plugin-fa-worker-cleaner-pinterrupt wa 8 0 0 1.62e3 0.00
+ acl-plugin-out-ip4-fa active 110988 27861510 0 1.04e2 251.03
+ dpdk-input polling 55639 27861510 0 4.62e1 500.76
+ ethernet-input active 111275 27861510 0 1.55e1 250.38
+ interface-output active 110988 27861510 0 1.21e1 251.03
+ ip4-input-no-checksum active 110988 27861510 0 1.95e1 251.03
+ ip4-lookup active 110988 27861510 0 2.89e1 251.03
+ ip4-rewrite active 110988 27861510 0 3.55e1 251.03
+ unix-epoll-input polling 54 0 0 2.43e3 0.00
+
+Performance
+-----------
+
++---------------------------------------+-------+-------------------+
+| Test Case | MPPS | Cycles per packet |
++---------------------------------------+-------+-------------------+
+| ethip4-ip4base | 18.26 | 136 |
++---------------------------------------+-------+-------------------+
+| ethip4ip4udp-ip4base-iacl1sl-10kflows | 9.134 | 273 |
++---------------------------------------+-------+-------------------+
+| ethip4ip4udp-ip4base-iacl1sf-10kflows | 11.06 | 226 |
++---------------------------------------+-------+-------------------+
+
+Input ACLS (SKX)
+~~~~~~~~~~~~~~~~
+
+.. figure:: /_images/ip4-2n-iacl.png
+
+Output ACLs (HSW)
+~~~~~~~~~~~~~~~~~
+
+.. figure:: /_images/ip4-3n-oacl.png
+
+Configuration
+-------------
+
+Stateful
+~~~~~~~~
+
+.. code-block:: console
+
+ $ sudo vppctl ip_add_del_route 20.20.20.0/24 via 1.1.1.2 sw_if_index 1 resolve-attempts 10 count 1
+ $ sudo vppctl acl_add_replace ipv4 permit src 30.30.30.1/32 dst 40.40.40.1/32 sport 1000 dport 1000, ipv4 permit+reflect src 10.10.10.0/24, ipv4 permit+reflect src 20.20.20.0/24
+ $ sudo vppctl acl_interface_set_acl_list sw_if_index 2 input 0
+ $ sudo vppctl acl_interface_set_acl_list sw_if_index 1 input 0
+
+Stateless
+~~~~~~~~~
+
+.. code-block:: console
+
+ $ sudo vppctl ip_add_del_route 20.20.20.0/24 via 1.1.1.2 sw_if_index 1 resolve-attempts 10 count 1
+ $ sudo vppctl acl_add_replace ipv4 permit src 30.30.30.1/32 dst 40.40.40.1/32 sport 1000 dport 1000, ipv4 permit src 10.10.10.0/24, ipv4 permit src 20.20.20.0/24
+ $ sudo vppctl acl_interface_set_acl_list sw_if_index 2 input 0
+ $ sudo vppctl acl_interface_set_acl_list sw_if_index 1 input 0
+
+Links
+~~~~~
+
+- `FD.io Security Groups overview <https://wiki.fd.io/view/VPP/SecurityGroups>`__
+- `Reflexive Access Control Lists <https://packetlife.net/blog/2008/nov/25/reflexive-access-lists/>`__
+- `Andrew Yuort's Blog on ACLs <http://stdio.be/blog/2017-12-09-Debugging-VPP-MACIP-ACLs/>`__
+
+.. _vppcop:
+
+FD.io VPP COP
+-------------
+
+IPv4/IPv6 white-lists using the FD.io VPP FIB, with support for multiple
+nested white-lists.
+
+Design notes:
+~~~~~~~~~~~~~
+
+- The cop graph nodes (input & white-list) make reuse of the FD.io VPP in FIB 2.0 implementation. Essentially
+ a successful lookup in the FIB, indicates that a packet has been white-listed and may be forwarded.
+
+- cop-input: Determines if the frame is IPv4 or IPv6, and forwards to ipN-copwhitelist graph node.
+
+- ipN-copwhitelist: uses the ip4_fib_[mtrie,lookup] functions to confirm the packet's ip matches a route in the white-list fib.
+
+- Match: if it matches, it is then either sent to the next whitelist or to the ip layer.
+
+- No Match: if it there is not match, it is sent to error-drop.
+
+Operational Data
+~~~~~~~~~~~~~~~~
+
+Note: the double-pass of the ip4-lookup and ip4-rewrite.
+
+.. code-block:: console
+
+ DUT1:
+ Thread 0 vpp_main (lcore 1)
+ Time 3.9, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ api-rx-from-ring active 0 0 53 4.20e4 0.00
+ dpdk-process any wait 0 0 1 1.75e4 0.00
+ fib-walk any wait 0 0 2 1.59e3 0.00
+ ip4-reassembly-expire-walk any wait 0 0 1 2.20e3 0.00
+ ip6-icmp-neighbor-discovery-ev any wait 0 0 4 1.14e3 0.00
+ ip6-reassembly-expire-walk any wait 0 0 1 1.50e3 0.00
+ lisp-retry-service any wait 0 0 2 2.19e3 0.00
+ statseg-collector-process time wait 0 0 1 2.48e3 0.00
+ unix-epoll-input polling 2800 0 0 3.15e6 0.00
+ vpe-oam-process any wait 0 0 2 7.00e2 0.00
+
+ Thread 1 vpp_wk_0 (lcore 2)
+ Time 3.9, average vectors/node 220.84, last 128 main loops 20.87 per node 190.86
+ vector rates in 1.0724e7, out 1.0724e7, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ TenGigabitEtherneta/0/0-output active 94960 20698112 0 1.03e1 217.97
+ TenGigabitEtherneta/0/0-tx active 94960 20698112 0 3.97e1 217.97
+ TenGigabitEtherneta/0/1-output active 92238 20698112 0 9.92e0 224.39
+ TenGigabitEtherneta/0/1-tx active 92238 20698112 0 4.26e1 224.39
+ cop-input active 94960 20698112 0 1.98e1 217.97
+ dpdk-input polling 95154 41396224 0 4.58e1 435.04
+ ethernet-input active 92238 20698112 0 1.59e1 224.39
+ ip4-cop-whitelist active 94960 20698112 0 3.24e1 217.97
+ ip4-input active 94960 20698112 0 3.13e1 217.97
+ ip4-input-no-checksum active 92238 20698112 0 2.23e1 224.39
+ ip4-lookup active 187198 41396224 0 3.08e1 221.14
+ ip4-rewrite active 187198 41396224 0 2.47e1 221.14
+ unix-epoll-input polling 93 0 0 1.35e3 0.00
+
+Performance
+~~~~~~~~~~~
+
++-------------------------------+-------+-------------------+
+| Test Case | MPPS | Cycles per packet |
++-------------------------------+-------+-------------------+
+| ethip4-ip4base | 18.81 | 132 |
++-------------------------------+-------+-------------------+
+| ethip4-ip4base-copwhtlistbase | 15.12 | 165 |
++-------------------------------+-------+-------------------+
+
+.. figure:: /_images/ip4-acl-features-ndr.png
+
+Configuration
+~~~~~~~~~~~~~
+
+Note: a new VRF 1 is created which holds the whitelist, which then
+applied to the interface 1.
+
+.. code-block:: console
+
+ $ sudo vppctl ip_add_del_route 10.10.10.0/24 via 1.1.1.1 sw_if_index 2 resolve-attempts 10 count 1
+ $ sudo vppctl ip_table_add_del table 1
+ $ sudo vppctl ip_add_del_route 20.20.20.0/24 vrf 1 resolve-attempts 10 count 1 local
+ $ sudo vppctl cop_whitelist_enable_disable sw_if_index 1 ip4 fib-id 1
+ $ sudo vppctl cop_interface_enable_disable sw_if_index 1
+
+Links
+~~~~~
+
+- `FIB 2.0: Hierarchical, Protocol Independent. <https://wiki.fd.io/images/7/71/FIB_2.0_-_Hierarchical,_Protocol_Independent..pdf>`__
+
+.. _vppflow:
+
+FD.io VPP Flow
+--------------
+
+FD.io VPP Flow adds the ability for FD.io VPP to support matching of
+flows and taking an associated action. This information is then used to
+program hardware accelerations such as those available on network cards,
+e.g. Intel® Ethernet Flow Director technology on the Intel® Ethernet
+Controller X710/XXV710/XL710.
+
+Supports
+~~~~~~~~
+
+Actions
+"""""""
+
+- Count: don't now what this does, presume it count's matches.
+- Mark: Associate a matched flow with arbitrary data such as vxlan tunnel, for a lookup in the redirect graph node.
+- Buffer Advance: Can be used advance to an encapsulated ethernet or ip header.
+- Redirect to node: When you see a packet from flow xyz, the next node in FD.io VPP is the indicated graph node.
+- Redirect to queue: When you see a packet from flow xyz, is to redirect to rx queue n.
+- Drop: When you see a packet from flow xyz, drop the packet (next node is error drop).
+
+Design Notes
+~~~~~~~~~~~~
+
+- Currently the only place in FD.io VPP that this is used, is to accelerate VXLAN bypassing the Ethernet and IP Layers.
+- Flow uses DPDK rte_flow API under the hood for those network interfaces programmed through DPDK.
+- Redirect to node: worth remember that if you are bypassing a graph, you are bypassing all the checks in the graph node, e.e time-to-live, crcs and the like.
+
+Operational Data
+~~~~~~~~~~~~~~~~
+
+FD.io CSIT numbers for VXLan do not use FD.io Flow support.
+
+Performance
+~~~~~~~~~~~
+
+FD.io CSIT numbers for VXLan do not use FD.io Flow support.
+
+Configuration
+~~~~~~~~~~~~~
+
+- `Flow API <https://git.fd.io/vpp/tree/src/vnet/flow/flow.h>`__
+
+.. _classifiers:
+
+FD.io VPP Classifiers
+---------------------
+
+The most flexible form of ACLs in FD.io VPP enable the user to match anywhere in the first
+80 bytes of the packet header.
+
+Configuration
+~~~~~~~~~~~~~
+
+Match an IPv6….
+
+.. code-block:: console
+
+ $ sudo vppctl classify table mask l3 ip6 dst buckets 64
+ $ sudo vppctl classify session hit-next 0 table-index 0 match l3 ip6 dst 2001:db8:1::2 opaque-index 42
+ $ sudo vppctl set interface l2 input classify intfc host-s0_s1 ip6-table 0
+
+Links
+~~~~~
+
+- `Overview of classifers <https://wiki.fd.io/view/VPP/SecurityGroups#Existing_functionality>`__
+- `FD.io VPP Classifiers Overview <https://wiki.fd.io/view/VPP/Introduction_To_N-tuple_Classifiers>`__
+- `FD.io VPP Classifiers CLI <https://docs.fd.io/vpp/19.04/clicmd_src_vnet_classify.html>`__
+- `Sample Code from Andrew Yourt <http://stdio.be/vpp/t/aytest-bridge-tap-py.txt>`__
diff --git a/docs/usecases/index.rst b/docs/usecases/index.rst
index 94135ea472f..3bcc129f6ae 100644
--- a/docs/usecases/index.rst
+++ b/docs/usecases/index.rst
@@ -13,6 +13,7 @@ extensive list, but should give a sampling of the many features contained in FD.
simpleperf/index.rst
vhost/index.rst
vmxnet3
+ acls
vppcloud
homegateway
contiv/index.rst