You can use a combination of the sysplex distributor and
the Cisco MNLB to provide workload balancing.
Procedure
Perform the following steps to set up sysplex distributor
to be the service manager for the Cisco MNLB:
- The Cisco router must be configured as a forwarding agent. The IP CASA control address (which is NOT the interface address
to the forwarding agent) must be advertised by the Cisco routing daemons.
This is not automatically done by Cisco and must be enabled by a Cisco
command. For more information on the commands, see online documentation
for Cisco at: http://www.cisco.com.
- Specify the SERVICEMGR keyword on the VIPADEFine statement
in the TCPIP profile.
- Specify the VIPASMparms statement in the TCPIP profile. Specify the same multicast group and UDP port on the VIPASMparms
statement in the TCPIP profile as are configured in the MNLB.
- Optionally, use MD5 authentication: Specify
the same password (MD5 key) on the VIPASMparms statement in the TCPIP
profile as is configured on the Cisco routers which will communicate
with the sysplex distributor. If a password (SMPASSword) is specified,
then the sysplex distributor will perform MD5 authentication for all
communications with the Cisco forwarding agents. For both the Cisco
forwarding agent and the sysplex distributor, the password is treated
as ASCII characters. No translation or conversion is performed. For
more information on MD5 authentication, see RFC 1321.
- If you are using V1R7 or later, configure all forwarding
agents with IP PIM DENSE-MODE to ensure that MNLB packets are forwarded
properly.
- If using the Cisco MNLB in a configuration
where there is an OSA adapter between a Cisco router and the destination
TCP/IP stacks such that multiple stacks are sharing the OSA, configure
Virtual MAC (VMAC) addressing on each of the destination TCP/IP stacks
or configure GRE tunnels on the Cisco routers. The sysplex
distributor stack is the only stack that registers the dynamic VIPA
to OSA. Therefore, if VMACs or GRE tunnels are not configured, OSA
will send all packets destined for the DVIPA to the sysplex distributor
stack (or to the default router stack if the OSA is not shared with
the sysplex distributor stack).
When configuring GRE tunnels,
you must configure them on the Cisco router such that any packets
destined for a DVIPA that are routed by the forwarding agents directly
to TCP/IP target stacks are encapsulated to the target stack's dynamic
XCF address or, if specified in the distributor, to the VIPAROUTE
target IP address. If the primary and backup TCP/IP stacks specify
different VIPAROUTE statements for a particular target, you must define
GRE tunnels for each target IP address that might be used.
For
more detailed information about configuring VMACs, see z/OS Communications Server: SNA Network Implementation
Guide, or see OSA-Express virtual MAC routing. For more
detailed information about configuring GRE tunnels, see the Cisco
router publications located at http://www.cisco.com.
- Special consideration must be made for each target stack
that will receive data from an OSA that is not shared with the distributor
stack. Connection load balanced IP packets routed to target
stacks that do not use GRE tunnels will arrive with a destination
address of the dynamic VIPA address. Only the OSA associated with
the distributor stack is aware of the dynamic VIPA address. If the
target stack is not the primary router for this OSA, or does not have
Virtual MAC (VMAC) addressing configured for this OSA, the OSA will
discard the IP packet. In this case, you must either configure VMAC
addressing for the OSA, configure GRE tunnels on the Cisco router,
or configure the target stack to be the primary router for the OSA.
If configuring GRE tunnels on the Cisco router, ensure that any packets
destined for a DVIPA that are routed by the forwarding agents directly
to TCP/IP target stacks are encapsulated to the target stack's dynamic
XCF address or, if specified in the distributor, to the VIPAROUTE
target IP address.
- Verification:
The Netstat VIPADCFG/-F report
may be used to verify the configuration. See z/OS Communications Server: IP System Administrator's
Commands for more information on this command.
Cisco's show
ip casa commands may be used to display MNLB information.
For more detailed information on these commands, see Cisco's online
documentation at: http://www.cisco.com.
Results
The following sample shows the VIPADYNAMIC statement:
VIPADYNAMIC
VIPADEFINE MOVEABLE IMMED SERVICEMGR 255.255.255.0 197.11.221.1
VIPASMPARMS SMMCAST 224.0.1.2 SMPORT 1637 SMPASS ABCD
VIPADIST 197.11.221.1 PORT 80 20 21 23
DESTIP 199.11.87.104
199.11.87.105
199.11.87.106
199.11.87.108
199.11.87.109
199.11.87.110
ENDVIPADYNAMIC
For more information on the VIPADYNAMIC
statement, see z/OS Communications Server: IP Configuration
Reference.