This section deals with migrating a queue manager when you are thinking of installing WebSphere® MQ Version 6.0 on an IPv6 network.
The IPv6 protocol can only be utilized by WebSphere MQ Version 6.0 or later. In order to make use of the IPv6 protocol, WebSphere MQ must be installed on a system that is IPv6 capable.
The preferred IP version that two systems use for communicating (if both IPv4 and IPv6 are available) is determined by a new queue manager attribute IPADDRV. This parameter only has an effect if the hostname resolves ambiguously to both an IPv4 address and an IPv6 address.
Using mapped addresses may require protocol translators in the IP network.
It is possible to come up with a number of different interconnection possibilities, and the following sections aim to help you understand how WebSphere MQ will work in each case.
Where three systems exist that are IPv4 only capable. Each system hosts a queue manager (QM1, QM2, and QM3) and each queue manager connects to the other two. All CONNAMEs in the cluster channel definitions are made using DNS names rather than IP addresses.
Enable QM1 to be able to use channels running over IPv6 as follows
Enable QM2 to be able to use channels running over IPv6 as for QM1 above.
With the queue manager IPADDRV attribute set to IPv6, the preference has been set for the queue manager to connect using the IPv6 protocol. If a channel from QM1 to QM3 has LOCLADDR set to a host name which resolves to an IPv6 address, or both IPv4 and IPv6 addresses (with the IPADDRV attribute set to IPv6, the IPv6 address will be returned as that is the preference), this channel will attempt to use the IPv6 protocol. If the IPv6 protocol installed on the QM1 host system is capable of using a mapped address then QM1 will communicate with QM3 over IPv6. Otherwise, the channel will fail to resolve CONNAME.
While QM3 remains a WebSphere MQ Version 5.3 or earlier queue manager, you will need to check that all CONNAMEs used to start a channel to QM3 do not resolve to an IPv6 address or dual IPv4 and IPv6 addresses where the IPv6 address could be returned. This would cause QM1 to attempt to start the channel over IPv6 which would fail with as it would be unable to resolve the CONNAME.
It is possible to upgrade a system to have dual IPv4 and IPv6 capability and still run a WebSphere MQ Version 5.3 or earlier queue manager on the system. While it is not recommended to run this type of configuration, as long as the addresses that are returned to this level of queue manager are either IPv4 or an IPv4 mapped version of an IPv6 address, this should work.
Where three systems exist that are IPv4 only capable. Each system hosts a queue manager (QM1, QM2, and QM3) and each queue manager connects to the other two. All CONNAMEs in the cluster channel definitions are made using IP addresses.
Because addresses have been specified instead of DNS names, to allow a queue manager to connect to another using the IPv6 protocol you will need to duplicate the definitions that use IPv4 addresses between them and provide them with IPv6 addresses instead. The original definitions that use IPv4 addresses will continue to work, but where you are looking to take advantage of the IPv6 protocol, you will need to connect using the new definitions.
Enable QM1 to be able to use channels running over IPv6 as follows
Enable QM2 to be able to use channels running over IPv6 as for QM1 above.
The queue managers can now connect as follows:
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