z/OS network settings

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This information discusses various aspects of the required network setup of the z/OS network.

z/OS VIPAs

Dynamic VIPAs are defined as MOVEABLE DISRUPTIVE VIPAs for:

  • SAP central services
  • NFS server
  • SAP network interface router (SAProuter)

z/OS UNIX System Services setup - BPXPRMxx

The following is an extract of the BPXPRMxx parmlib member used on all LPARs. It shows network definitions for the TCP/IP stacks and NFS definitions. For further details, refer to Planning Guide for SAP on IBM® Db2 for z/OS.

…
…
USERIDALIASTABLE('/etc/ualiastable')
…
…
FILESYSTYPE TYPE(NFS) /* NFS client  */
            ENTRYPOINT(GFSCINIT)
            PARM('DISABLELLA(y)')
            ASNAME(MVSNFSCS,'SUB=MSTR')
FILESYSTYPE TYPE(ZFS)     /* ZFS  */
            ENTRYPOINT(IOEFSCM)
            ASNAME(DFSZFS,'SUB=MSTR')
NETWORK     DOMAINNAME(AF_UNIX)
            DOMAINNUMBER(1)
            MAXSOCKETS(10000)
            TYPE(IBMUDS)
NETWORK     DOMAINNAME(AF_INET)
            DOMAINNUMBER(2)
            MAXSOCKETS(64000)
            TYPE(INET)
            RESOLVER_PROC(RESOLVER)
NETWORK     DOMAINNAME(AF_INET6)
            DOMAINNUMBER(19)
            MAXSOCKETS(32000)
            TYPE(INET)

MOUNT FILESYSTEM('OMVS.ZFS.COHPLEX.SAPMNT')
         MOUNTPOINT('/sapmnt')
         TYPE(ZFS)
         MODE(RDWR)
         AUTOMOVE
MOUNT FILESYSTEM('OMVS.ZFS.COHPLEX.USRSAP')
         MOUNTPOINT('/usr/sap')
         TYPE(ZFS)
         MODE(RDWR)
         AUTOMOVE
MOUNT FILESYSTEM('OMVS.ZFS.COHPLEX.TRANS')
         MOUNTPOINT('/usr/sap/transAll')
         TYPE(ZFS)
         MODE(RDWR)
         AUTOMOVE
MOUNT FILESYSTEM('OMVS.ZFS.COHPLEX.HA2.USRSAP')
         MOUNTPOINT('/usr/sap/HA2')
         TYPE(ZFS)
         MODE(RDWR)
         AUTOMOVE
…
…

z/OS COH1 – Unix System Services network settings

This section describes the network settings for LPAR COH1. The settings are also used for LPAR COH2, and COH3 with LPAR specific settings changed accordingly.

File /etc/resolv.conf
DATASETPREFIX SYS1.TCP
TCPIPJOBNAME TCPIP
BOECOH1: HOSTNAME coh1vipa
BOECOH2: HOSTNAME coh2vipa
BOECOH3: HOSTNAME coh3vipa
DOMAINORIGIN boeblingen.de.ibm.com
LOADDBCSTABLES SJISKANJI
NSinterAddr  9.152.120.241
NSinterAddr  9.152.64.172
NSportAddr 53
ResolveVia UDP
ResolverTimeout 5
 
TCP/IP profile
;-----------------------------------------------------------------------
;Dynamic VIPA Definition
VIPADYNAMIC
VIPARANGE DEFINE MOVEABLE DISRUPTIVE 255.255.255.240 10.101.5.192
VIPARANGE DEFINE MOVEABLE DISRUPTIVE 255.255.255.240 10.101.6.192
VIPARANGE DEFINE MOVEABLE DISRUPTIVE 255.255.255.252 9.152.20.160
VIPARANGE DEFINE MOVEABLE NONDISRUPTIVE 255.255.255.248 9.152.20.176
ENDVIPADYNAMIC
;-----------------------------------------------------------------------
;Source IP for NFS Server VIPA (required for NFSv3 clients)
SRCIP
JOBNAME MVSNFSHA 10.101.5.193
ENDSRCIP
;-----------------------------------------------------------------------
;Settings for the TCP layer
TCPCONFIG
    INT 10           ; KeepAlive Interval 10 Min. (Default 120)
    SENDG TRUE       ; KeepAlive Probes with 1 Byte 'garbage'
    UNRESTRICTL      ; LOW PORTS 1-1023 not reserved  (Default)
    TCPRCVB  65536   ; TCPReceiveBuffer in Bytes (z/OS 2.1 or 2.2: Default 64k)
    TCPSENDB 65536   ; TCPSendBuffer in Bytes    (z/OS 2.1 or 2.2: Default 64k)
;-----------------------------------------------------------------------
; Allow TCP/IP to determine the max MTU size on PATH
IPCONFIG
PATHMTUDISCOVERY
;-----------------------------------------------------------------------
; Allow HiperSockets to use multiple write support and exploit zIIPs
GLOBALCONF
IQDMULTIWRITE
ZIIP IQDIOMULTIWRITE
;-----------------------------------------------------------------------
;Device and Link definitions
DEVICE  VLINK1   VIRTUAL  0
LINK    VLINK1   VIRTUAL  0 VLINK1
;
;- z/OS 2.1 or 2.2 Use INTERFACE statement for HiperSockets - -
INTERFACE   HIPERE4
DEFINE   IPAQIDIO
IPADDR   10.101.4.68/26
SOURCEVIPAINTERFACE VLINK1
CHPID E4
;
INTERFACE COH2L1
DEFINE IPAQENET
IPADDR 9.152.20.136/22
PORTNAME OSAPORT
MTU 1492
NONROUTER
;
INTERFACE COHVS2
DEFINE IPAQENET
IPADDR 10.101.4.131/26
PORTNAME COHGE1
SOURCEVIPAINTERFACE VLINK1
MTU 8992
OLM NOISOLATE
PRIROUTER
;
;-----------------------------------------------------------------------
; HOME internet (IP) addresses of each link in the host
HOME
  10.101.4.210             VLINK1     ; VIPA
;
 PRIMARYINTERFACE VLINK1
;-----------------------------------------------------------------------
;IP routing information
 BEGINROUTES
 ; IPV4
 ; NETWORK          MASK   FIRST HOP    LINK          PCKTSZ
   ROUTE 9.152.20.0/22     =            COH1L1    MTU 1492
   ROUTE DEFAULT           9.152.20.1   COH1L1    MTU 1492
ENDROUTES
;-----------------------------------------------------------------------
; Start all the defined devices.
  START COH2L1
  START COHVS2
  START HIPERE4  ; HIPERSOCKET
;-----------------------------------------------------------------------
;Reserve ports for the following servers
PORT
    111 TCP RPCBIND1                     ; RPC SERVICE
    111 UDP RPCBIND1                     ; RPC SERVICE
   1223 TCP OMVS                         ; OE TELNET SERVER
   1389 TCP BBOLDAP                      ; PORT NUMBER FOR BBOLDAP
   8803 TCP RMFDDS01 BIND 9.152.20.177   ; RMF DDS VIPA FOR SAP SYSPLEX MONITORING
GLOBALTCPIPDATA(/etc/resolv.conf)
GLOBALIPNODES(/etc/hosts)
COMMONSEARCH
;-----------------------------------------------------------------------
; Flush the ARP tables every 5 minutes
ARPAGE 5
;-----------------------------------------------------------------------
;Specify maximum length for the connection request queue created by
; the socket call listen().
SOMAXCONN 1024 (z/OS 2.1 or 2.2: Default 1024)
 
OMPROUTE start procedure
//OMPROUTE PROC
//OMPROUTE EXEC PGM=OMPROUTE,REGION=4096K,TIME=NOLIMIT,
// PARM=('POSIX(ON)',
//       'ENVAR("_CEE_ENVFILE=DD:STDENV")/')
//STDENV   DD PATH='/etc/omproute.stdenv',
//         PATHOPTS=(ORDONLY)
//SYSPRINT DD PATH='/tmp/omproute.stdout',
//            PATHOPTS=(OWRONLY,OCREAT,OTRUNC),
//            PATHMODE=(SIRUSR,SIWUSR,SIRGRP,SIWGRP)
//SYSOUT   DD PATH='/tmp/omproute.stderr',
//            PATHOPTS=(OWRONLY,OCREAT,OTRUNC),
//            PATHMODE=(SIRUSR,SIWUSR,SIRGRP,SIWGRP)
//
//SYSERR   DD SYSOUT=*
//CEEDUMP  DD SYSOUT=*
 
OMPROUTE environment variables
RESOLVER_CONFIG=/etc/resolv.conf
OMPROUTE_FILE=/etc/omproute.conf
OMPROUTE_DEBUG_FILE=/tmp/omproute.debug
 

Define the OMPROUTE procedure to RACF®. At a TSO command prompt, enter the following commands:

rdefine started omproute.* stdata(user(stcuser) group(stcgroup))
setr raclist(started) refresh
OSPF routing parameters

The important things to note about the routing definitions are:

  • The MTU must be the same for communication by all OSPF daemons on the same Ethernet segment.
  • Each possible interface should be defined with the proper MTU size because the default MTU is 576 for a route that is not in the routing file.
  • The order of the definitions must match the order of the IP addresses in the TCP/IP profile HOME statement.

OMPROUTE configuration in /etc/omproute.conf:

Area
     Area_Number=0.0.0.0
     Stub_Area=NO
     Authentication_Type=None
     Import_Summaries=YES
;
ROUTERID=10.101.4.131;
;
GLOBAL_OPTIONS ignore_undefined_interfaces=yes
;
Interface
    IP_Address=9.152.20.136
    Name=COH2L1
    Subnet_Mask=255.255.252.0
    MTU=1492
;
OSPF_Interface
     IP_Address=10.101.4.131
     Name=COHVS2
     Subnet_Mask=255.255.255.192
     Attaches_To_Area=0.0.0.0
     MTU=8992
     Cost0=15
     Router_Priority=11
     Parallel_OSPF=Primary
     Hello_Interval=10
     Dead_Router_Interval=40
     Retransmission_Interval=5
     DB_Exchange_Interval=120
;
OSPF_Interface
     IP_Address=10.101.4.67
     Name=HIPERE4
     Subnet_Mask=255.255.255.192
     Attaches_To_Area=0.0.0.0
     MTU=8192
     Cost0=10
     Router_Priority=11
     Parallel_OSPF=Primary
     Hello_Interval=10
     Dead_Router_Interval=40
     Retransmission_Interval=5
     DB_Exchange_Interval=120
;
;OSPF_Interface statement for a virtual (VIPA) interface
;
OSPF_Interface
    IP_Address=10.101.4.211
    Name=VLINK1
    Subnet_Mask=255.255.255.255
    Attaches_To_Area=0.0.0.0
    Cost0=1
    MTU=8992
;
;OSPF_Interface statement for VIPARANGE
;
OSPF_Interface
    IP_Address=10.101.5.192
    Subnet_Mask=255.255.255.240
    Name=VIPL1
    Cost0=1
    MTU=8992