LLXBK | Back to Index page

| Prolog Control Block Contents LLXBK DSECT LLXITEM 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.

LLXBK Prolog | Top of page

     NAME       : HCPLLXBK
     DESCRIPTION: Link Layer Index Table entry
     DSECT      : LLXBK
     FUNCTION   :
                  The LLXBK structure represents an array of sessions
                  (NIDBK pointers) registered for a specific Link ID.
                  The Link ID is the MAC address.
                  The LLXBK structure is variable length.
     LOCATED BY -
       LANIDTBL - LAN Link ID Table (MLTBK)
     CREATED BY :
                  Link Layer functions in module HCPLLN.
     DELETED BY :
                  Link Layer functions in module HCPLLN.
     RELOCATION CONSIDERATIONS : None
     LLXID definition -
       LLXVLAN represents an IEEE VLAN group, or an
       internally defined code.  The following table
       describes the purpose of each LLXVLAN code:
         LLXVLAN | Frames which may be delivered
         --------|-------------------------------------------
         x'0000' | Untagged (or NULL tagged) frames
         x'0xxx' | VLAN tagged frames
         x'0FFF' | Not a valid VLAN group
         x'1000' | ANY frames (the target is VLAN ANY)
         x'1xxx' | Routers (for unclaimed frames)
       LLXMAC represents a MAC address identifying a
       device (or group of devices) as the destination
       of a network frame.

LLXBK Control Block Content | Top of page

     LLXBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      LLXBK          Link Layer Index Table entry
          Link ID (Key) for LAN ID Table is VLAN||MAC.
    0000    0 Bitstring    8 LLXID (0)      Link ID
    0000    0 Bitstring    6 LLXMAC         MAC Address for this entry
    0006    6 Bitstring    2 *              VLAN ID for this entry
          Counters.
    0008    8 Signed       2 LLXMAX         Maximum for this list
    000A   10 Signed       2 LLXCOUNT       Number of entries
              00000001       LLX_INIT       1 Initial allocation
              00000008       LLX_INCR       8 Incremental allocation
              000003E8       LLX_MAX        1000 Maximum allocation
              0000000C       LLXHDRLN       *-LLXBK Length of header
          Array of device pointers begins here (see LLXITEM).
              0000000C       LLXLIST        * Start of device list
    000C   12 Address      4 LLXPTR1        Pointer to first device
          Overlay LLXID for the LAN Router Table.
            Key = VLAN||ipver||routertype.
    0000    0 Bitstring    4 LLXRXID (0)    Router ID (VLAN||ipver||type)
    0000    0 Signed       2 LLXRXVID       VLAN ID for this entry
    0002    2 Bitstring    1 LLXRXVER       IP Version (4=IPv4, 6=IPv6)
    0003    3 Bitstring    1 LLXRXTYP       Router Type (Pri, Sec, MC)
    0004    4 Bitstring    4 *              Unused for LLXRXID
    0008    8 Bitstring    4 *              LLXMAX, LLXCOUNT
          OBJECT - LLXITEM
            One LLXITEM exists for each entry in LLXLIST.

     LLXITEM DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      LLXITEM        Link Layer Index Table entry
    0000    0 Address      4 LLXPTR         Pointer to device(1) entry
              00000004       LLXPTRLN       *-LLXITEM Length of one list
                                            entry
              00000002       LLX_EXP        2 Bits to shift to multiply
                                            length
              00000004       LLXNEXT        * Offset to next entry

LLXBK Storage Layout | Top of page

    *** LLXBK - Link Layer Index Table entry
    *
    *     +-----------------------------------------+-------------+
    *   0 |                 LLXMAC                  |/////////////|
    *     +-------------+-------------+-------------+-------------+
    *   8 |   LLXMAX    |  LLXCOUNT   |         LLXPTR1           |
    *     +-------------+-------------+---------------------------+
    *  10
    *
    *** LLXBK - Link Layer Index Table entry

    *** Overlay for LLXID in LLXBK
    *
    *     +-------------+------+------+---------------------------+
    *   0 |  LLXRXVID   |:RXVER|:RXTYP|///////////////////////////|
    *     +-------------+------+------+---------------------------+
    *   8 |///////////////////////////| C
    *     +---------------------------+
    *
    *** Overlay for LLXID in LLXBK

    *** LLXITEM - Link Layer Index Table entry
    *
    *     +---------------------------+
    *   0 |          LLXPTR           | 4
    *     +---------------------------+
    *
    *** LLXITEM - Link Layer Index Table entry

LLXBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    LLX_EXP        0000 00000002
    LLX_INCR       000A 00000008
    LLX_INIT       000A 00000001
    LLX_MAX        000A 000003E8
    LLXCOUNT       000A
    LLXHDRLN       000A 0000000C
    LLXID          0000
    LLXLIST        000A 0000000C
    LLXMAC         0000
    LLXMAX         0008
    LLXNEXT        0000 00000004
    LLXPTR         0000
    LLXPTRLN       0000 00000004
    LLXPTR1        000C
    LLXRXID        0000
    LLXRXTYP       0003
    LLXRXVER       0002
    LLXRXVID       0000

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:28:57 EDT.
Copyright IBM Corporation, 1990, 2020