Ali,
This is Part 2.
Now "Echo". I thought it was generally a "good thing", assuming this =
"Echo" parameter refers to what I know as "Echo Defeat". I expect "Echo" =
"N" means suppress the "echo" and "Echo" "Y" means don't worry about the =
"echo" but it could be the other way round - in fact it probably is. =
This possible "Echo Defeat" topic prompted me to dig into my notes =
again, this time from an SDLC presentation.
<start "Echo Defeat" notes>
Echo Defeat
-----------
Problems have arisen on subarea connections between NCPs because data =
can be "echoed" by the transmission medium. This can cause an NCP to =
react to a frame which it sent originally rather than having come from =
the other link station.
The solution adopted has been to ignore the address generated for the =
link stations at the primary and secondary ends of the link and to =
assign, essentially, a "sequence" address from X'01' to X'7E'. (If more =
are needed, the addresses are assigned from X'01' again.) When the =
primary sends a frame containing an address, after the XID exchange, it =
is this address, as assigned by the primary NCP. When the secondary =
sends a frame containing an address, after the XID exchange, it is this =
assigned address ORed with X'80'. Thus the primary
and secondary (scanners in 3725, 3720 and 3745) can ignore =
"echoed"frames.
To allow for migration when one end of the link does not have a scanner =
which supports "echo defeat", the use of this function is agreed during =
XID Format 2 exchange (bit 4 of byte X'23').
"Echo defeat" during XID exchange is accomplished by checking whether a =
received XID contains the same subarea and NETID. If it does, the XID is =
ignored.
Although not covered in the CESEARCH data base item which covers this =
function, it must be assumed that the address used during loading of the =
NCP is the generated address since this should match the address defined =
in the Link IPL Ports table specified in the MOSS files.
<end "Echo Defeat" notes>
Actually I got curious - as I always do - about the "new ground" - or =
"old ground" reworked - implied by these IPL parameters so, knowing I =
had access to the 3745 manuals web page (also the page for the NCP =
manuals) I decided I should look up the manual rather than speculating. =
The manual is the 3745 Advanced Operations Guide SA33-0097-09.
The manual says that "Echo defeat" is required only for satellite =
transmissions - where, indeed, echo is to be expected. However, I =
thought I'd heard this could happen on other media types - or was I =
talking to myself <g>.
It's as well I did get curious since it is very evident that "Other" for =
"External Line Speed" doesn't mean anything by itself. Strange that I =
haven't seen this before. I expect 3 is just fine for 19.2 Kbps.
Also, since, according to your comments alongside "External Line Speed", =
you are using dial-up modems "with modems dialing each other" which I =
take to be modems which dial when they detect DTE is raised (and =
disconnect normally when DTE drops I expect). Thus, these modems operate =
with nonswitched procedures as far as your NCPs are concerned.
However, one parameter is now very important; your ENABLTO equivalent =
must allow for the time taken for the modem to make a connection which =
can be 10 to 20 seconds or so I would expect for a Public Switched =
Telephone Network dial operation. Time it, double it, and use that value =
for the BUILD statement ENABLTO operand and the "Enable Timer". I expect =
0 which you have specified is also acceptable but you should know that, =
rather confusingly, the "Enable Timer" (and ENABLTO)is used for other =
3745-modem lead timings (except DSR dropping after DTR) and so having =
an upper limit will enable you better to check any problems before and =
during loading. Also specifying 0 for ENABLTO is not an option.
SDLC Controller Address: If you've coded this you'd better know the =
default PU statement ADDR operand value used by the channel-attached =
NCP. The NCP Resource Definition Reference says the following: "ADDR is =
not valid for a point-to-point (where SDLCST is coded on the LINE =
statement) subarea connection. In this configuration, NDF and NCP =
administer the appropriate address." Well, thanks but what is this =
"appropriate address"?
Fortunately, we have the description of the TADDR operand of the LINE =
statement to help us.
<begin TADDR>
TADDR
=20
>>-----------------><
| |
--TADDR=3Dchars--
Use: NCP or EP
Default: See text
Specifies a symbolic link station address for this NCP when it is a type =
4 physical unit on a subarea or peripheral link.
chars is the 2-digit hexadecimal representation of the EBCDIC character =
you code as the symbolic address. If you omit TADDR, the default is the =
EBCDIC representation of the subarea address of this NCP. For example, =
if this NCP has a subarea address of 3 and a symbolic address of D, code =
TADDR=3DC4. However, if you do not code TADDR, the default address for =
this controller is X'03' (the hexadecimal representation of the subarea =
address).
If you omit TADDR and the subarea address is 255, the default is 254.
If NCP is for a tributary controller on a BSC line, ... <For 3 =
paragraphs of arcana and a table before we get back to subarea =
connections again>.
This keyword is required if you specify MODE=3DSECONDARY and do NOT code =
SDLCST on LINE for a secondary multipoint subarea link. TADDR is not =
valid if you code MODE=3DPRIMARY and do not code SDLCST on LINE for =
primary multipoint subarea links. <Not our concern - note the NOT I =
converted to upper case.>
For peripheral links, ... <Not our concern>.
For casual connection, ... <Again not out concern - and, in any case, =
logically, such links are also "peripheral">.
<Finally, explicit statements of how the default is determined:>
The default for TADDR is the rightmost two digits of the hexadecimal =
representation of the subarea address coded on the SUBAREA keyword on =
the BUILD definition statement. This rule has two exceptions. If the =
rightmost two digits are X'00', the default is X'01'. If the rightmost =
two digits are X'FF', the default is X'FE'. The examples in Table 2-78 =
illustrate the calculation of the default.
Table 2-78. Examples of TADDR Defaults on the LINE Definition Statement
SUBAREA on BUILD Hexadecimal Equivalent Rightmost Two Digits TADDR =
Default
1 0001 01 =
01
12346 303A 3A =
3A
4608 1200 00 =
01
4607 11FF FF =
FE
<end TADDR>
No, I also need to read the paragraph starting "chars" about ten times =
before the convoluted language begins to make some sense - but this is =
NCP. Just take note of the points about the hexadecimal representation =
of the subarea number. This is what "NCP and NDF administer the =
appropriate address" is all about I expect. I don't have sample listings =
to hand but it may be that your NDF output shows the default for TADDR.=20
If this is all a bit puzzling - and you'd be excused for thinking so - I =
believe it's a consequence of the text structure still showing signs of =
how it was before configurable subarea link stations was introduced in =
ACF/NCP V1R3 - yes, that far back. Configurability required that the =
primary PU ADDR value and secondary LINE TADDR value were assigned =
dynamically. Thus you don't get to specify either. However, the loading =
process requires that the loading side is primary and the loaded side is =
secondary and, since the loaded/secondary side doesn't have an NCP =
inside it - by definition - the "Link IPL Ports" need to reflect the =
"preconfigurable" definitions. Well, that's clear to me if it still =
isn't to you <g>.
Of course, once you've specified the correct "SDLC Controller Address", =
all may work.
Trying to check also in the NCP Resource Definition Guide in the rather =
short section "Remote Loading and Activation of a Link-Attached NCP", I =
was reminded as follows: "For a complete description of the process for =
remote loading and activation using CLDP or NCP, refer to NCP, SSP, and =
EP Generation and Loading Guide", specifically Chapter 10 "Remote =
Loading and Activation". - and this is where we came in because there is =
the paragraph you quoted - and there is no further help - but this is =
NCP, after all.
Chris Mason
----- Original Message -----
From: "Ali Serdar Yakut" <[EMAIL PROTECTED]>
Newsgroups: bit.listserv.ibm-main
To: <[email protected]>
Sent: Tuesday, 20 December, 2005 10:34 AM
Subject: Remote 3745 Definition
Hi there,
I do not know if this is the right list to post this, but I'm trying
anything for help.
I have got a very urgent situation.
I am trying to have a configuration like -
VTAM1 - NCP1 - NCP2
NCP1 is loaded in a channel attached 3745. NCP2 will be on a link attached
3745.
In the NCP generation and loading guide the following is stated:
You can perform a remote initial load over a TSS or HPTSS SDLC link or
over a nonswitched X.21 link if the remote communication controller has
the remote IPL ports defined. The remote initial load can transfer the
NCP or PEP load module from the host, activate it, and save it on the
remote hard disk. There is a minimum release requirement of NCP V4R2 with
VTAM V3R2 in order to save the module to the remote hard disk.
I have created remote IPL port using LKP function in the communication
controller of NCP2 - the parameters for the Port are:
Line Address: 35
Direct/External: External
Duplex: D
Enable Timer: 0 (Timeout yok)
Transmit two flags: y
Transmit flags between frames: y
NRZI: y
DX facility:y
Switched: N
Ring: N
Answer: N
Echo: N
Datarate: High
External Line Speed: Other (not 9600 or 56K my connection is 19.2K DialUp
with modems dialing each other)
SDLC Controller Address: C1 (I have coded this - but could not get from the
guides what this is used for)
So what should I do now? Create a line and PU (Type4) in NCP1 -
for this connection?
I have made so, but I can not see the PU as online on my VTAM, when there is
no NCP loaded in the remote controller. Can anybody help me with the
procedure- the guides all keep it as trivial, just create remote IPL port,
and load, but no procedure.
I will appreciate for any contribution.
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