Add c_network_eth_word_align_len = 2.

libraries/base/common/src/vhdl/common_network_layers_pkg.vhd

@@ -51,9 +51,13 @@ PACKAGE common_network_layers_pkg IS
   -- |                Frame Check Sequence                                  |
   -- |------------------------------------------------------------ // ------|
   --
+  -- . The word_align field is optional in and can only exist inside the
+  --   firmware, not on the link. It is removed by the TSE before transmit
+  --   and inserted by TSE after receive,
   
   -- field widths in bits '_w' or in bytes '_len', '_min', '_max', '_sz'
   CONSTANT c_network_eth_preamble_len      : NATURAL := 8;
+  CONSTANT c_network_eth_word_align_len    : NATURAL := 2;  -- to align 14 octets eth header at 32b word
   CONSTANT c_network_eth_mac_addr_len      : NATURAL := 6;
   CONSTANT c_network_eth_mac_addr_w        : NATURAL := c_network_eth_mac_addr_len*c_8;
   CONSTANT c_network_eth_type_len          : NATURAL := 2;