[dts] [PATCH V1] doc/dts_gsg/sys_reqs:add known issue after update scapy 2.4.4

[Zhimin Huang]

*.compare scapy 2.4.4 with 2.4.3 and support new packet layer.

Signed-off-by: Zhimin Huang <zhiminx.huang at intel.com>
---
 doc/dts_gsg/sys_reqs.rst | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/doc/dts_gsg/sys_reqs.rst b/doc/dts_gsg/sys_reqs.rst
index 332304a..c549646 100644
--- a/doc/dts_gsg/sys_reqs.rst
+++ b/doc/dts_gsg/sys_reqs.rst
@@ -81,6 +81,31 @@ DTS uses python module scapy to forge or decode packets of a wide number of prot
 
 scapy 2.4.4: support packet layer PFCP and GTPPDUSessionContainer
 
+.. code-block:: console
+
+   pip3 install scapy==2.4.4
+
+.. note::
+    There are some differences between scapy 2.4.4 and scapy 2.4.3 about the packet layer, the details refer to the
+    table as follows.
+
+.. table::
+
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+    | Compare scapy 2.4.3 with scapy 2.4.4                                                                                                                            |
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+    | Layer                  | packet in scapy 2.4.3           | packet in scapy 2.4.4                         | Comments                                             |
+    +========================+=================================+===============================================+======================================================+
+    | PPP                    | PPP(proto=0xc021)               | PPP(b\'\\xc0\\x21\')                          | PPP protocol filed length is 1 byte in scapy2.4.4    |
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+    | L2TP                   | L2TP(\'\\x00\\x00\\x00\\x11\')  | L2TP(b\'\\x00\\x00\\x00\\x11\')               | L2TP is byte type in scapy2.4.4                      |
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+    | PFCP                   | N/A                             | PFCP(S=1, seid=1)                             | PFCP is not supported in scapy2.4.3                  |
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+    | GTPPDUSessionContainer | N/A                             | GTPPDUSessionContainer(type=0, P=1, QFI=0x34) | GTPPDUSessionContainer is not supported in scapy2.4.3|
+    +------------------------+---------------------------------+-----------------------------------------------+------------------------------------------------------+
+
+
 Install DPDK Test Suite on tester
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-- 
1.8.3.1