NAME       : HCPETHBK
 DESCRIPTION: IEEE Ethernet Frame
 DSECT      : ETHBK
 FUNCTION   :
              The ETHBK maps the fields in an Ethernet Frame for a
              layer 2 datagram as defined by IEEE Architecture.
 CREATED BY : Not Applicable
 DELETED BY : Not Applicable
  NCHORED   - Not Applicable
 RELOCATION CONSIDERATIONS : None
 COMMENTS   :
              - This control block does NOT represent a CP object.
              Instead, it maps the IEEE Ethernet Frame for a
              layer 2 LAN data transmission.

 ETHBK DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      ETHBK          IEEE Ethernet Frame
0000    0 Bitstring    6 ETHDEST        +00 Destination MAC Address
0006    6 Bitstring    6 ETHSRC         +06 Source MAC Address
          0000000C       ETHMACLN       *-ETHBK Length of ETHBK MAC
                                        addresses
000C   12 Bitstring    2 ETHTYPE        +0C Type of next element
          0000000E       ETHNEXT        * +0E Next element begins here
          0000000E       ETHBKLN        *-ETHBK Length of ETHBK
      Ethernet Extension for 802.1q VLAN Tag.
000E   14 Bitstring    2 ETHXTAG        +0E Priority||Canonical||VLANID
0010   16 Bitstring    2 ETHXTYPE       +10 Type of next element (after
                                        TAG)
          00000004       ETHVLANB       *-ETHXTAG Length of VLAN TAG Info
          00000012       ETHXNEXT       * +12 Next element begins here
      The value of 1536 was chosen by the IETF to denote a TYPE
      to provide the ability to distinguish between Ethernet v2
      (DIX) from the 802.3 Ethernet encapsulations. The value
      1536 or higher in a LENGTH/TYPE field of an Ethernet
      classifies the field as a TYPE (Ethernet v2).
          00000600       ETHV2          1536 MIN Length/TYPE for Ethernet
                                        v2
      Generic Frame Header (starts with Ethernet type).

          
*** ETHBK - IEEE Ethernet Frame
*
*     +-----------------------------------------+-------------+
*   0 |                ETHDEST                  |   (006)-    |
*     +---------------------------+-------------+-------------+
*   8 |         -ETHSRC           |  ETHTYPE    |  ETHXTAG    |
*     +-------------+-------------+-------------+-------------+
*  10 |  ETHXTYPE   | 12
*     +-------------+
*
*** ETHBK - IEEE Ethernet Frame

 
Symbol         Dspl Value
-------------- ---- -----
ETHBKLN        000C 0000000E
ETHDEST        0000
ETHMACLN       0006 0000000C
ETHNEXT        000C 0000000E
ETHSRC         0006
ETHTYPE        000C
ETHVLANB       0010 00000004
ETHV2          0010 00000600
ETHXNEXT       0010 00000012
ETHXTAG        000E
ETHXTYPE       0010