FRMHDR Back to Index page
 
Prolog 
Control Block Contents 
   FRMHDR DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

 
  FRMHDR Control Block Content Top of page
  




 FRMHDR DSECT
Top of page


Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      FRMHDR         IEEE Ethernet Frame
0000    0 Bitstring    2 FRMTYPE        Ethernet Type
          00000002       FRMDATA        * Frame data
      VLAN Tag Control Frame (ETHTYPE = x8100)
          00000002       VLANCTL        * Beginning of IEEE VLAN Tag
0002    2 Bitstring    2 VLANTAG        +00 Priority||Canonical||VLANID
      Masks defined for VLANTAG
          0000E000       VLANPRMK       X'E000' Mask on VLANTAG Priority
                                        bits
          00001000       VLANCNMK       X'1000' Mask on VLANTAG Canonical
                                        bit
          00000FFF       VLANIDMK       X'0FFF' Mask on VLANTAG VLAN ID
                                        bits
0004    4 Bitstring    2 VLANTYPE       +02 Type of next element
          00000006       VLANNEXT       * +04 Next element begins here
          00000004       VLANCTLN       *-VLANCTL Length of VLANCTL
      Ethernet 802.3 LLC Header (FRMTYPE <= 1500)
0000    0 Bitstring    2 FRMETHLN       +00 FRMTYPE == 802.3 Data Length
0002    2 Bitstring    3 FRMLLC (0)     +02 LLC fields (DSAP||SSAP||CNTL)
0002    2 Bitstring    1 FRMDSAP        +02 DSAP
0003    3 Bitstring    1 FRMSSAP        +03 SSAP
0004    4 Bitstring    1 FRMCNTL        +04 Control
          00000005       LLCDATA        * LLC Frame Data begins here
0005    5 Bitstring    3 SNAPOUI        +05 Organizational Unique
                                        Identifier
0008    8 Bitstring    2 SNAPTYPE       +08 Ethernet Frame Type in SNAP
                                        HDR
          0000000A       SNAPDATA       * +0A Data following SNAP header
      ARP Frame (FRMTYPE = x'0806')
          00000002       ARPFRAME       * Beginning of ARP frame header
0002    2 Bitstring    2 ARPHWTYP       +00 Hardware Type (Ethernet=0001)
0004    4 Bitstring    2 ARPPRTYP       +02 Protocol Type (IP=0800)
0006    6 Bitstring    1 ARPHWLEN       +04 Hardware Address Length (06)
0007    7 Bitstring    1 ARPPRLEN       +05 Protocol Address Length (04)
0008    8 Bitstring    2 ARPFUNC        +06 ARP function code
          .... ...1      ARPRQ          X'0001' ARPRQ - ARP Request
                                        function
          .... ..1.      ARPRP          X'0002' ARPRP - ARP Reply
                                        function
000A   10 Bitstring    6 ARPHWSRC       +08 Hardware Source Address (MAC)
0010   16 Bitstring    4 ARPPRSRC       +0E IPv4 Source Address
0014   20 Bitstring    6 ARPHWTRG       +12 Hardware Target Address (MAC)
001A   26 Bitstring    4 ARPPRTRG       +18 IPv4 Target Address
          0000001C       ARPFRMLN       *-ARPFRAME Length of ARP frame
 
 
  FRMHDR Storage Layout Top of page
  
          
*** FRMHDR - IEEE Ethernet Frame
*
*     +-------------+
*   0 |  FRMTYPE    | 2
*     +-------------+
*
*** FRMHDR - IEEE Ethernet Frame
          
*** Overlay for FRMDATA in FRMHDR
*
*                   +-------------+-------------+
*   0 ...         2 |  VLANTAG    |  VLANTYPE   | 6
*                   +-------------+-------------+
*
*** Overlay for FRMDATA in FRMHDR
          
*** Overlay for FRMHDR in FRMHDR
*
*     +-------------+------+------+------+--------------------+
*   0 |  FRMETHLN   |:DSAP |:SSAP |:CNTL |      SNAPOUI       |
*     +-------------+------+------+------+--------------------+
*   8 |  SNAPTYPE   | A
*     +-------------+
*
*** Overlay for FRMHDR in FRMHDR
          
*** Overlay for FRMDATA in FRMHDR
*
*                   +-------------+-------------+------+------+
*   0 ...         2 |  ARPHWTYP   |  ARPPRTYP   |:HWLEN|:PRLEN|
*     +-------------+-------------+-------------+------+------+
*   8 |  ARPFUNC    |                ARPHWSRC                 |
*     +-------------+-------------+---------------------------+
*  10 |         ARPPRSRC          |        ARPHWTRG-          |
*     +-------------+-------------+-------------+-------------+
*  18 |   -(014)    |         ARPPRTRG          | 1E
*     +-------------+---------------------------+
*
*** Overlay for FRMDATA in FRMHDR
 
 
  FRMHDR Cross Reference Top of page
  
 
Symbol         Dspl Value
-------------- ---- -----
ARPFRAME       0008 00000002
ARPFRMLN       001A 0000001C
ARPFUNC        0008
ARPHWLEN       0006
ARPHWSRC       000A
ARPHWTRG       0014
ARPHWTYP       0002
ARPPRLEN       0007
ARPPRSRC       0010
ARPPRTRG       001A
ARPPRTYP       0004
ARPRP          0008 02
ARPRQ          0008 01
FRMCNTL        0004
FRMDATA        0000 00000002
FRMDSAP        0002
FRMETHLN       0000
FRMLLC         0002
FRMSSAP        0003
FRMTYPE        0000
LLCDATA        0004 00000005
SNAPDATA       0008 0000000A
SNAPOUI        0005
SNAPTYPE       0008
VLANCNMK       0002 00001000
VLANCTL        0000 00000002
VLANCTLN       0004 00000004
VLANIDMK       0002 00000FFF
VLANNEXT       0004 00000006
VLANPRMK       0002 0000E000
VLANTAG        0002
VLANTYPE       0004
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:50:18 EDT.
Copyright IBM Corporation, 1990, 2022