Hello Darryl,
Am 15.04.2020 um 15:05 schrieb a4g atl <a4ginatl2@xxxxxxxxx>:
I don't remember all the details as to when twinax was removed from the hardware but essentially SNA (if you use it) runs within TCP/IP.
Since parts of SNA run over Twinax (and in the mainframe area) over coax cable, I don't understand why you refer to IP in this context. The removal of Twinax is not related to the Invention of EE (see below).
As a result, using SNA over TCP/IP will be slower than APPC/APPN which is a SNA protocol.
Yes, of course. Especially on oder hardware, IP proves to be very demanding on CPU. Also, there's loss of bandwidth through encapsulation overhead.
Basically, your system is almost certainly using TCP for all communications hence APPC/APPN will be slower as it has to convert the APPC/APPN to run over TCP/IP and then at the target end, convert it back to
APPN/APPC.
Depends on OS level and hence Hardware. Your statement is true only for comparably new hardware with the necessary processor power and OS support.
You are most likely referring to Enterprise Extender, which uses UDP/IP as data link protocol. Enterprise Extender is available in i5/OS V5R4 and newer. EE is the only way to network machines with IOP-less IOAs.
Older releases support MPTN ("AnyNet") but the APPN-over-IP flavour in V4 is not very stable, as I found out: Network outages can make the code be stuck in some state and you'll need to vary off and back on controller descriptions on both sides to force recovery. If machines are networked over VPN, the chance of outages is real.
Before EE, and without crappy MPTN, the usual way for APPN communications in LANs was to use Token Ring or Ethernet with 802.2 DLC ("SDLC like") framing with direct 1:1 connections from MAC to MAC.
I'm interested in knowing how fast real world transfers are. Not by guessing "Token Ring has 16M, so it's like 1,5 MBytes/s", but by real measurement.
The only advantage to using APPC/APPN is that APPC/APPN is more secure and if someone is hacking your line, its way more difficult to interpret the SNA packets.
Ehm. No. When you shovel the data trough a EBDIC-ASCII-Converter, clear text is visible in the same manner as when tapping a TCP session. The EBDIC thing is the only hindrance and not a real difficult at all.
When you're using encrypted communication, that's harder. :-)
:wq! PoC
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