Network Map File (NETMAP)

The network map file is a VSAM KSDS that contains network definition information, including the network names for the local node and other (adjacent) nodes in the network, the communication addresses for use by the API, and various control information used by IBM® Connect:Direct®

To estimate the size of the network map, you must determine how many nodes are needed and the communications used for each node. This includes determining the node IDs for your network (including the local node name), all APPLIDs (SNA type), and all TCP/IP addresses (or DNS names) for the nodes.

The following chart defines the basic size of records for planning how large to make the network map:

Record Size (in bytes) Description/Comments
Control Records 250 Base records for NDM control
ADJACENT.NODE 124 Basic adjacent node information
ALT.COMM 32 + 59(n) Alternate communications addresses. Each set adds 1 to “n”.
LDNS 278 Holder of the DNS name for an ADJACENT.NODE


74 + x 1 per node definition and each segment (x) adds up to:

Conact Name - 40, Phone - 40, Description - 255

IPv6 232 This record exists for an ADJACENT.NODE if the node is defined with any of the following items specified:
  • IPv6 address for TCP/IP
  • the API record specifies an IPv6 record
  • SOURCEIP is specified.
UDT 96 UDT support has been removed. Please update your Netmap to delete all UDT ADJACENT NODEs.
TCP API 60 Used to specify the address for API
APPLIDs 40 + 8x SNA APPLIDs for a node. Add 1 to x for each node ID specified
xNODE.LUS 28 + 8(x) If either PNODE or SNODE.LUS is specified, add 1 to x for each node name specified.
Node Usage 1024 1 US record for each Adjacent Node

For example, if the network map contains 25 nodes with API APPLIDs in each of the 25 nodes, it requires approximately the space illustrated in the following table.

Netmap Definitions Number Size (in bytes)
Control Records + Local node 3 362
APPLIDs 25 nodes with 20 APPLIDs 5350
Node Usage 25 25600
Total 78 records 34412

For those installations that make frequent updates to the network map, it is recommended that the allocation be done on a cylinder boundary and be at least one cylinder more than currently needed. CA/CI splits may take place as additions and updates are done.