SNAX/XF and SNAX/APN Configuration and Management Manual

WAN Subsystem Objects for SNAX Processes
SNAX/XF and SNAX/APN Configuration and Management Manual—425836-006
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SNAX Line Handler DEVICE Modifiers
NT21BPAGES n
The value of NT21BPAGES specifies the number of pages allocated in the line handler
extended segment for SNAX/APN operation. The value of 0 for NT21BPAGES results
in 4000 pages being allocated for SNAX/APN, allowing more than 2000 parallel
sessions without causing congestion. The actual number of sessions that can be
established may be limited further by storage requirements which are not included in
this value.
SNAX/APN needs to have at least 48 pages allocated in the line handler segment for
its operation. If the specified value in between 1 and 47 for NT21BPAGES, SNAX/APN
automatically allocates 48 pages. If the specified value in between 49 and 3999,
SNAX/APN allocates the number of pages in NT21BPAGES.
Specifying the default value results in SNAX/APN allocating 4000 pages.
To change the NT21BPAGES value, issue an SCF ALTER DEVICE command to the
WAN subsystem. For example:
STOP DEVICE $ZZWAN.#SNAP1
ALTER DEVICE $ZZWAN.#SNAP1, NT21BPAGES 3000
REJ
REJ specifies how SNAX handles out-of-sequence I-frames for SDLC secondary lines
using two-way simultaneous (TWS) communication.
When REJ is specified, SNAX sends an SDLC REJ S-frame to request retransmission.
When REJ is not specified, SNAX sends an SDLC RR frame to request
retransmission.
SNAX always accepts REJ frames. SNAX always uses REJ frames on SDLC primary
lines using TWS.
The REJ frame is used on TWS communication to reject I-frames received with an
out-of-sequence Ns (number sent) value. Assume, for example, that station A sends
three I-frames (Ns = 0, 1, 2) to station B and station B receives the (Ns 0) and (Ns 2)
frames but gets a frame-check sequence error on the (Ns 1) frame. The (Ns 2) frame is
out of sequence, so station B sends a REJ frame with Nr = 1. Nr=1 tells station A to
retransmit frames (Ns 1) and (Ns 2).
To reset to not using REJ S-frames, issue an SCF ALTER DEVICE command to the
WAN subsystem; for example:
STOP DEVICE $ZZWAN.#SNAP1
ALTER DEVICE $ZZWAN.#SNAP1, RESET REJ
Default: 0 (4000)
Range: 48-4000
Default: No REJ frames used