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Solstice X.25 9.2 Administration Guide

LAPB and WAN Parameters

You can access the LAPB and WAN Parameters window from the Link Editor.

The parameter values are stored in the link configuration files /etc/opt/SUNWconn/x25/config/link_config_nnnn.cfg, where nnnn is the four-digit number that indicates the link number (for example, the file link_config_0004.cfg contains the parameters for link number 4).

Use the LAPB and WAN Parameters screen to configure the datalink and physical layer parameters used by a LAPB link.

LAPB Parameters

The LAPB layer parameters are:

Ack Timer (T1) (t1_timer)

The period, in tenths of a second, during which the LAPB software expects to receive an acknowledgment to an outstanding I-frame or during which LAPB expects a response to a sent unnumbered frame. The valid range for values of this parameter is between 1 and 3000.

P-bit Timer (pf_timer)

The period, in tenths of a second, during which the LAPB software expects to receive a frame with the F-bit set to 1 in response to a command with the P-bit set to 1. This value should be less than that specified for the Ack Timer. The valid range for values of this parameter is between 1 and 3000.

Reject Timer (reject_timer)

The period, in tenths of a second, during which the LAPB software expects to receive a reply to a sent Reject frame. The valid range for values of this parameter is between 1 and 10000.

Busy-state Timer (busy_timer)

The period, in tenths of a second, during which the LAPB software waits for an indication of the clearance of a busy condition at the other end of the link. The valid range for values of this parameter is between 1 and 30000.

Link Idle Timer (idle_timer)

The period, in tenths of a second, during which the LAPB software expects to receive a frame from the other end of the link. If this timer expires, the Poll/Final cycle--which might result in link disconnection--is initiated. A zero value disables this function. The valid range for values of this parameter is between 0 and 32000.

Max. RR Delay (rr_ack_delay)

The maximum delay, in tenths of a second, before transmitting a delayed Receiver Ready. The value for this parameter must be significantly lower than the Ack Timer value. The valid range for values of this parameter is 0 to 3000.

Max Tries (N2) (n2_count)

The maximum number of times that an I-frame (information frame) is sent following the expiration of the Ack Timer, the P-bit Timer, or the Reject Timer. It also limits the number of times Receive Ready with P-bit set is sent when the remote side is busy and the Busy Timer expires. The valid range for values of this parameter is 1 to 255.

Max UnACKed IPDUs (unack_max)

The maximum number of unacknowledged I-frames that can be received before the Receive Ready acknowledging those I-frames must be sent. The valid range for values of this parameter is 0 to 127 for modulo 128, and 0 to 7 for modulo 8.

Transmit Probe (local_probe)

The position within a window at which the LAPB software sends an I-frame with the P-bit set, to ask for an acknowledgment from the receiver. The valid range for values of this parameter is 0 to 127.

MLP Priority (mlp_priority)
Note -

This parameter appears in the LAPB and WAN Parameters window when the Link Type is set to MLP in the Link Editor Window. In this instance, to access the LAPB and WAN Parameters window, you must call up the MLP Parameters window, then double click on the SLP you want to configure. For more information, see "MLP Parameters".

This parameter defines how many unacknowledged frames can be sent on one line before the next line is used. Setting this correctly forces traffic to be distributed between the lines in an MLP link. The values you set depend on the absolute speed of each line, and on the relative speeds of your lines. In general, don't set an MLP Priority of less than 3. If your lines operate at 64kbps, or more, you should increase the MLP Priority.

The following combinations of values provide efficient (90%) line use in two-line MLP configurations:

Link Conformance

Ignore UA if in ERROR state I (ign_ua_error)

When the connection is in an Error state, ignore any Unnumbered acknowledgment frames received.

FR on receipt of FR if in ERROR (frmr_frmr_error)

When the connection is in an Error state, retransmit a Frame Reject if one is received.

FR on Inv. Resp. if in ERROR (frmr_invrsp_error)

When the connection is in an Error state, transmit a Frame Reject if an invalid Frame Response is received.

Send FR if S-Frame & no P-bit (sframe_pbit)

If an S-frame is received without the P-bit set, send a Frame Reject.

No DM on entry to ADM state (no_dm_adm)

Do not transmit a DM on entry to the ADM state.

Abandon X.32 registration on SABM(sabm_in_x32)

Abandon X.32 registration if a SABM is received.

ISO8882 Conformance (iso8882)

Run the link so that it is conforms exactly to the specifications in the ISO 8882 standard.

Initial state of link is "Off" (initial_down)

When the Solstice X.25 software comes up, the link is off. To switch it on subsequently, use the linkstart command.

Enable X.32 Authentication (x25_x32_enable_authen)

When this is set to Yes, an X.32 identity and signature can be configured for a subnetwork. X.32 authentication procedures are used with dial-up configurations to prevent people from dialing in without permission This is a client-only implementation of X.32.

Signature (x25_x32_sign)

An X.32 signature of up to 32 hexadecimal characters. Do not use whitespace.

Identity (x25_x32_identity)

An X.32 identity of up to 32 hexadecimal characters. Do not use whitespace.

WAN Parameters (V25bis)

The physical layer parameters for a single LAPB link are:

Calling Procedures (connect_proc)

The type of calling procedure to use: None or V25bis.

V.25bis Call Request Timer (v25_callreq)

Set this if you are using the V.25 Calling Procedures. This timeout is only needed if the network does not support call fail indications. The valid range for values for this parameter, in tenths of a second, is between 60 and 300.