Category: DEVICE

Converting from TCP/IP devices to interfaces

TCP/IP supports devices for IP V4 using statements like

DEVICE PORTA MPCIPA
  LINK ETH1 IPAQENET PORTA
...
HOME ...
     10.1.1.2 ETH1
...

BEGINRoutes 
...
ROUTE DEFAULT      10.1.1.1 ETH1 MTU 1492 
ENDRoutes 
                                                                   

START PORTA

z/OS TCP has said these DEVICE and LINK statements should be converted these to use the INTERFACE statement, because the LINK and DEVICE statements will be withdrawn in a future release.

The interface statement basically merges the DEVICE, LINK and the relevant part of HOME into one INTERFACE statement. You can use Interface statements for IP V4 and IP V6. They are easier to configure and activate than DEVICE and LINK statements

The equivalent interface statement is 

INTERFACE ETH1 
    DEFINE IPAQENET 
    CHPIDTYPE OSD 
    IPADDR 10.1.1.2 
    PORTNAME PORTA

The command can be written on one (or more lines). You can have

   INTERFACE JFPORTCP4
DEFINE IPAQENET
; this is a comment 
CHPIDTYPE OSD IPADDR 10.1.1.2 PORTNAME PORTA

( Personally I would not; I prefer the command to start in column 1, and following lines indented).

If you name the interface the same as the LINK statement, you will not need to change any routing statements.

The easiest way of implementing the change is to make the change and restart TCP/IP.

The changes you need to make are

  • Replace the DEVICE and LINK statements with the INTERFACE statement
  • Remove the IP address from the HOME
  • Change the START from the port to the interface name

Check it has been defined

After you have restarted TCP/IP

tso netstat home

gave

MVS TCP/IP NETSTAT CS V2R4       TCPIP Name: TCPIP   
Home address list: 
LinkName:   LOOPBACK 
  Address:  127.0.0.1
    Flags: 
IntfName:   ETH1 
  Address:  10.1.1.2 
    Flags:  Primary 
IntfName:   LOOPBACK6
  Address:  ::1 
    Type:   Loopback 
    Flags:

The command

tso netstat devlinks

Gave

IntfName: ETH1              IntfType: IPAQENET   IntfStatus: Ready
    PortName: PORTA     Datapath: 0402     DatapathStatus: Ready 
    CHPIDType: OSD            SMCR: Yes 
    PNetID: *None*            SMCD: Yes 
    TRLE: OSATRL1E 
    Speed: 0000001000 
    IpBroadcastCapability: No 
    CfgRouter: Non                   ActRouter: Non 
    ArpOffload: Yes                  ArpOffloadInfo: Yes 
    CfgMtu: None                     ActMtu: 8992 
    IpAddr: 10.1.1.2/0 
    VLANid: None                     VLANpriority: Disabled 
    ReadStorage: GLOBAL (4096K) 
    InbPerf: Balanced 
    ChecksumOffload: Unsupported     SegmentationOffload: No 
    SecClass: 255                    MonSysplex: No 
    Isolate: No                      OptLatencyMode: No 
  Multicast Specific: 
    Multicast Capability: Yes 
    Group             RefCnt        SrcFltMd 
    -----             ------        -------- 
    224.0.0.1         0000000001    Exclude 
      SrcAddr: None 
  Interface Statistics: 
...
                                                            
IPv4 LAN Group Summary 
LanGroup: 00001 
  Name              Status      ArpOwner          VipaOwner 
  ----              ------      --------          --------- 
  ETH1              Active      ETH1              Yes

where interesting fields are

  • IntfName: ETH1 the interface name
  • IntfType: IPAQENET the interface type
  • IntfStatus: Ready the status of the interface
  • PortName: PORTA the port name
  • Datapath: 0402 what device is being used
  • IpAddr: 10.1.1.2/0 the IP address of the z/OS end of the connection

If you are using DEVICE and LINK the output will have LnkName: ETH1 instead of IntfName: ETH1.

If you are brave…

you can remove the LINK and DEVICE definitions from the active system and activate the INTERFACE, then at a later date, update the TCP/IP configuration file.

You need to

  • stop the existing definition
  • remove the HOST entry for the device
  • delete the DEVICE and LINK from the running configuration
  • activate the interface statement
  • start the interface

Stop the device

V TCPIP,TCPIP,STOP,PORTA

You cannot use V TCPIP,TCPIP,STOP,ETH1 because it says device not found.

Remove the HOME entry for the link

Copy the home statements into a file, remove the entry you do not want, then issue the V…OBEY… on that file. This replaces the active HOME entries.

If you use TSO NETSTAT HOME, the IP address should not be present.

Delete the link and device from the active configuration

One you have removed the HOME statements, and TSO NETSTAT HOME does not show any entries for the device, you can create members DELLINK

DELETE LINK ETH1

and member DELDEV

DELETE DEVICE PORTA

Use the V…OBEY… in turn on each file. You cannot put both commands in one file, as the commands are processed asynchronously and the delete link command may still be executing when the delete device is executed, and then so fail.

The TSO NETSTAT DEVLINKS command should show the link is not in the output.

Activate the interface

Put your interface definition statements into a file and activate it using 

V TCPIP,TCPIP,OBEY,USER.Z24C.TCPPARMS(JFACE41)

My definition defines an interface with name JFPORTCP4.

Start the interface 

V TCPIP,TCPIP,STA,JFPORTCP4

Test it

TSO NETSTAT HOME should show the IP address, and you should be able to ping it.

You can use TSO NETSTAT DEVLINKS (INTFNAME JFPORTCP4 to display the interface.

Make the change permanent

You will need to:

  • Comment out/remove the PATH and LINK definitions
  • Remove/comment out the IP address and link from the HOME statement
  • Remove the start of the device
  • Add the interface definition. This could be done using an INCLUDE statement
  • Add a start of the interface (or add it to the include file).
  • Use V…OBEY… with the start-up configuration file, or restart TCP/IP
  • Change your documentation!