X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fprog_guide%2Flpm6_lib.rst;h=d1aea91ca99c14ffed9d2713e7e9ed5cf44280cf;hb=3855b4150037142435b5c1f4195e44c142785f1f;hp=abc5adbf9f2f612f29dcf75aba47be011a4ea320;hpb=ba9e05cb6b002016b01adf4e8700f206f3d04fd6;p=dpdk.git diff --git a/doc/guides/prog_guide/lpm6_lib.rst b/doc/guides/prog_guide/lpm6_lib.rst index abc5adbf9f..d1aea91ca9 100644 --- a/doc/guides/prog_guide/lpm6_lib.rst +++ b/doc/guides/prog_guide/lpm6_lib.rst @@ -1,32 +1,5 @@ -.. BSD LICENSE - Copyright(c) 2010-2014 Intel Corporation. All rights reserved. - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions - are met: - - * Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in - the documentation and/or other materials provided with the - distribution. - * Neither the name of Intel Corporation nor the names of its - contributors may be used to endorse or promote products derived - from this software without specific prior written permission. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2010-2014 Intel Corporation. LPM6 Library ============ @@ -53,7 +26,7 @@ several thousand IPv6 rules, but the number can vary depending on the case. An LPM prefix is represented by a pair of parameters (128-bit key, depth), with depth in the range of 1 to 128. An LPM rule is represented by an LPM prefix and some user data associated with the prefix. The prefix serves as the unique identifier for the LPM rule. -In this implementation, the user data is 1-byte long and is called "next hop", +In this implementation, the user data is 21-bits long and is called "next hop", which corresponds to its main use of storing the ID of the next hop in a routing table entry. The main methods exported for the LPM component are: @@ -75,7 +48,7 @@ The main methods exported for the LPM component are: Implementation Details ~~~~~~~~~~~~~~~~~~~~~~ -This is a modification of the algorithm used for IPv4 (see Section 19.2 "Implementation Details"). +This is a modification of the algorithm used for IPv4 (see :ref:`lpm4_details`). In this case, instead of using two levels, one with a tbl24 and a second with a tbl8, 14 levels are used. The implementation can be seen as a multi-bit trie where the *stride* @@ -108,9 +81,11 @@ This is not feasible due to resource restrictions. By splitting the process in different tables/levels and limiting the number of tbl8s, we can greatly reduce memory consumption while maintaining a very good lookup speed (one memory access per level). -.. image40_png has been renamed -|tbl24_tbl8_tbl8| +.. figure:: img/tbl24_tbl8_tbl8.* + + Table split into different levels + An entry in a table contains the following fields: @@ -231,5 +206,3 @@ Use Case: IPv6 Forwarding ------------------------- The LPM algorithm is used to implement the Classless Inter-Domain Routing (CIDR) strategy used by routers implementing IP forwarding. - -.. |tbl24_tbl8_tbl8| image:: img/tbl24_tbl8_tbl8.*