If I understand the question correctly, I'd recommend Enterprise Extender (EE). It's likely to be the more future proof option in various ways, and that'll be helpful. EE is also proving to be broadly interoperable across long spans of time.
z/OS 1.4 supported IPv6 fairly well but not for EE, so it looks like you'll have to use IPv4 on both ends, for the UDP connectivity that EE uses. It wasn't really until z/OS 2.1 that EE was fully IPv6 enabled. If IPv6 is a necessity (and probably even if not) then, going from memory (please double check this) you should be able to set up an IPv6 IPsec tunnel between z/OS 1.4 and z/OS 2.2 -- i.e. the tunnel gets established using IPv6 addresses at both ends -- and then run IPv4 EE across that tunnel. Bear in mind that the security characteristics of that IPsec tunnel will be governed by its lowest denominator: z/OS 1.4. Speaking of security, EE also supports SNA Session-Level Encryption (SLE) and always has, although I'd want more than that. SNA SLE only supports the DES and 3DES algorithms. The usual, wise advice applies here about trying to bring up z/OS 1.4 and the applications it's running to a supported z/OS release as expeditiously as possible. -------------------------------------------------------------------------------------------------------- Timothy Sipples IT Architect Executive, Industry Solutions, IBM Z & LinuxONE, Multi-Geography E-Mail: sipp...@sg.ibm.com ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN