Configuring the 5-Bit to 8-Bit SLS Conversion Feature

This procedure is used to configure the 5-Bit to 8-Bit SLS Conversion feature using the chg-stpopts command with the slscnv parameter.

The slscnv parameter of the chg-stpopts command has three values: on, off, and perls.

slscnv=on – 5-bit to 8-bit conversion is performed on all linksets in the EAGLE, regardless of what the value of the slsci parameter of the ent-ls or chg-ls command is for the specific linkset. If the asl8=yes parameter of either the ent-ls or chg-ls commands is assigned to the linkset, no SLS conversion is performed.
slscnv=off – 5-bit to 8-bit conversion is not performed on the linksets in the EAGLE, regardless of what the value of the slsci parameter of the ent-ls or chg-ls command is for the specific linkset.
slscnv=perls – 5-bit to 8-bit SLS conversion is only performed on the MSUs arriving at the EAGLE on linksets that have the asl8=no parameter assigned to them, and leaving the EAGLE on linksets that have the slsci=yes parameter assigned to them. The asl8 and slsci parameters are configured with either the ent-ls or chg-ls commands.

5-Bit to 8-Bit SLS conversion is performed based on the values assigned to the slsci and asl8 parameters for the linkset and the slscnv parameter of the chg-stpopts command.

Note:

The slsci and asl8 parameters can be specified only for linksets containing ANSI adjacent point codes.

The slsci parameter indicates whether the 5-bit to 8-bit SLS conversion feature is used to select signaling links for outgoing messages on the specified link set. If the slsci=yes parameter is specified, the EAGLE replaces any 5-bit SLS values contained in received messages with a random 8-bit value before they are used by the EAGLE to select the outgoing signaling link in that linkset. The 5-bit to 8-bit SLS conversion is also controlled by the slscnv parameter of the chg-stpopts command.

The asl8 parameter shows if the node adjacent to the EAGLE is sending MSUs with 8-bit SLSs. If the asl8=yes parameter is specified with the lst=a parameter (a linkset containing access signaling links), this indicates that the originator of the MSUs is generating 8-bit SLSs. For other linkset types, the asl8=yes parameter indicates that the adjacent node is converting 5-bit SLSs to 8-bit SLSs. The SLS in MSUs received by the EAGLE on a linkset that has the asl8=yes parameter assigned to it will not be converted. These MSUs are assumed to contain 8-bit SLSs. If the asl8=no parameter is specified for the linkset, the SLS will be converted to an 8-bit SLS. The value of the asl8 parameter is only displayed in the rtrv-ls command output when a specific linkset is being displayed with the rtrv-ls:lsn=<linkset name> command.

The interaction between the slsci and asl8 parameters of the ent-ls command and the slscnv parameter of the chg-stpopts command is shown in Table 3-9.

Table 3-9 Signaling Link Selector (SLS) Conversion (ANSI Linksets Only)

CHG-STPOPTSSLSCNV Parameter Value	Outgoing Linkset SLSCI Parameter Value	Incoming Linkset ASL8 Parameter Value	Result
ON	Not Applicable	YES	The adjacent node is sending 8-bit SLSs. No SLS conversion is performed on MSUs received on this linkset.
ON	Not Applicable	NO	The adjacent node is not sending 8-bit SLSs. 5-bit to 8-bit SLS conversion on MSUs received on this linkset.
OFF	Not Applicable	YES	The adjacent node is sending 8-bit SLSs. No SLS conversion is performed on any linksets.
OFF	Not Applicable	NO	The adjacent node is not sending 8-bit SLSs. 5-bit to 8-bit SLS conversion is not performed on all linksets.
PERLS*	YES	YES	The adjacent node is sending 8-bit SLSs. No SLS conversion is performed.
PERLS*	YES	NO	The adjacent node is not sending 8-bit SLSs. 5-bit to 8-bit SLS conversion is performed.
PERLS*	NO	YES	The adjacent node is sending 8-bit SLSs. No SLS conversion is performed.
PERLS*	NO	NO	The adjacent node is not sending 8-bit SLSs. 5-bit to 8-bit SLS conversion is not performed.
When the `slscnv=perls` parameter is specified with the `chg-stpopts` command, 5-bit to 8-bit SLS* conversion is only performed on the MSUs arriving at the EAGLE on linksets that have the `asl8=no` parameter of the `ent-ls` command assigned to them, and leaving the EAGLE on linksets that have the `slsci=yes` parameter of the `ent-ls` command assigned to them.

When a 5-bit ANSI SLS is converted to an 8-bit ANSI SLS, the three most significant bits of the SLS are set using a function of originating point code and incoming signaling link. This ensures that MSUs with the same originating point code, SLS, and incoming signaling link will always have the same SLS after the conversion, guaranteeing that the MSUs arrive at the destination in the same sequence that they were sent.

5-bit to 8-bit SLS conversion is performed under these conditions.

The incoming linkset is an ANSI linkset, a linkset containing an ANSI adjacent point code.
The asl8=no parameter of the ent-ls or chg-ls command is assigned to the incoming linkset.
The outgoing linkset is an ANSI linkset.
The slscnv=on parameter of the chg-stpopts command is specified
The slscnv=perls parameter of the chg-stpopts command is specified and slsci=yes parameter of the ent-ls or chg-ls command assigned to the outgoing linkset.
The three most significant bits of the SLS in the MSU are zero.

All ANSI MSUs originating from the EAGLE have an 8-bit SLS.

The EAGLE also converts ANSI SLSs to ITU SLSs, and ITU SLSs to ANSI SLSs.

When an ITU SLS is converted to an ANSI SLS, the ITU SLS is always converted to an ANSI 5-bit SLS. If the MSU containing the converted SLS is rerouted because of a link outage, the SLS may be converted from a 5-bit SLS to an 8-bit SLS.

When an ANSI SLS is converted to an ITU SLS, the ANSI SLS is always converted to an ITU 4-bit SLS.

The EAGLE does not convert a 4-bit ITU SLS to an 8-bit ANSI SLS.

The 5-bit to 8-bit SLS conversion takes place during the routing process, after the linkset is selected, but before the signaling link is selected. The ITU to ANSI SLS conversion takes place during the ANSI to ITU MSU conversion and after the outgoing signaling link is chosen.

Display the existing value for the slscnv parameter by entering the rtrv-stpopts command.
The value for the slscnv parameter is shown in the SLSCNV field. This is an example of the possible output.
```
rlghncxa03w 08-12-17 16:02:05 GMT  EAGLE5 40.0.0
STP OPTIONS
-----------------------
SLSCNV              on
```
Note:
The rtrv-stpopts command output contains other fields that are not used by this procedure. If you wish to see all the fields displayed by the rtrv-stpopts command, see the rtrv-stpopts command description in Commands User's Guide.

If the slscnv parameter is not being changed, no further action is necessary. The procedure is finished.

If you wish to change the slscnv parameter value, continue the procedure with 2.
Change the slscnv parameter value using the chg-stpopts command.
For this example, the value of the slscnv parameter is being changed from on to perls. Enter this command.chg-stpopts:slscnv=perls. When this command has successfully completed, this message should appear.
```
rlghncxa03w 08-12-07 00:22:57 GMT  EAGLE5 40.0.0
CHG-STPOPTS: MASP A - COMPLTD
```
Verify the changes using the rtrv-stpopts command.
This is an example of the possible output.
```
rlghncxa03w 08-12-17 16:02:05 GMT  EAGLE5 40.0.0
STP OPTIONS
-----------------------
SLSCNV           perls
```
Note:
The rtrv-stpopts command output contains other fields that are not used by this procedure. If you wish to see all the fields displayed by the rtrv-stpopts command, see the rtrv-stpopts command description in Commands User's Guide.

Back up the new changes using the chg-db:action=backup:dest=fixed command.

These messages should appear, the active Maintenance and Administration Subsystem Processor (MASP) appears first.

BACKUP (FIXED) : MASP A - Backup starts on active MASP.
BACKUP (FIXED) : MASP A - Backup on active MASP to fixed disk complete.
BACKUP (FIXED) : MASP A - Backup starts on standby MASP.
BACKUP (FIXED) : MASP A - Backup on standby MASP to fixed disk complete.

Figure 3-7 Configuring the 5-Bit to 8-Bit SLS Conversion Feature

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