5.1 Introduction to the MTP Layer

5.2 The MTP Configuration

5.2.1 General Configuration Section

5.2.2 Links Configuration Section

5.2.3 Network Service Access Points (NSAPs) Section

5.2.4 Route Definition Section

5.2.5 Linkset Definition Section

5.3 Sample MTP Configuration File

5.4 MTP Configuration Considerations

5.4.1 Configuring Routes to Non-Adjacent Nodes

5.4.2 Using Priorities

5.4.3 Using Routing Masks

5.4.4 Considerations for Configuring for Japan-NTT Protocol Variant

5.4.5 Sample MTP Configuration File for Japan-NTT Protocol Variant

5.5 MTP Configuration Parameters Reference

5.5.1 General Parameters

5.5.2 Link Parameters

MTP 3 Link Parameters

MTP 2 Link Parameters

5.5.3 Network Service Access Point (NSAP) Parameters

5.5.4 Routing Parameters

5.5.5 Link Set Parameters

5.1 Introduction to the MTP Layer

The SS7 MTP layer 3 has two primary functions.

• Message routing and distribution

• Signaling network management

Message routing and distribution includes both the routing of outgoing messages to their specified destinations and the distribution of incoming messages to the appropriate user part or application. The SS7 MTP implementation uses a flexible configuration capability to support a wide variety of network routing and addressing requirements.

Signaling network management's job is to reconfigure the signaling network as needed to maintain signaling capability in the case of failures or congestion. This includes redirecting traffic away from failed links and/or signaling points (SPs), restoring traffic to restored links/SPs, and exchanging route status with adjacent SPs. The MTP 3 layer supports all required ANSI and ITU-T network management procedures without intervention from the user parts/applications.

The primary objects represented by MTP layer 3 are signaling links, routes, linksets, and Network Service Access Points (NSAPs).

Links define physical signaling links between the TX board and the adjacent signaling points. One link configuration must be performed for each physical signaling link. The attributes of a link include the point code of the adjacent signaling point, protocol variant employed on the link (ITU-T or ANSI), point code length, maximum packet length, various timer values, membership in a linkset, and others.

Linksets are groups of from one to 16 links that directly connect two signaling points. Although a linkset usually contains all parallel signaling links between 2 SPs, it is possible to define parallel link sets. Each signaling link defined is assigned membership in exactly one link set.

Routes specify the destination signaling points (or sub-networks (clusters) when route masks are employed) that are accessible from the target node. Each route is assigned a direction - up or down. One up route is required for the actual point code assigned to the signaling point being configured and for each point code that is to be emulated. Up routes are used to identify incoming messages that are to be routed up to the applications/user parts. One down route is required for each remote signaling point/network/cluster that is to be accessible from the SP being configured.

Down routes are used to route outgoing messages to the appropriate signaling links. Each down route is assigned to each linkset that can be used to reach that destination. Each link set within the route's associated combined linkset may have an optional priority assigned, such that MTP routing will choose the highest priority available link set when routing an outgoing packet to a particular destination.

Note: Priorities range from 0 (highest) to 15 (lowest) for both links and linksets. Priorities must be assigned starting at zero and incremented by one for each lower priority (there can be no gaps in priority assignment).

Figure 2 illustrates the relationship between links, linksets, and routes.

Figure 2. Links, Link Sets, and Routes

Network service access points (NSAPs) define the SS7 user parts, or applications, which are users of the MTP service. Each NSAP is associated with one user part or application (as identified by the service indicator field of a message) and one protocol variant (ITU-T or ANSI). Figure 3 illustrates the concept of NSAPs:

Figure 3. Network Service Access Points (NSAPs)

If multiple protocol variants are configured on the same MTP 3 instance (same board) then two NSAPs are required for each user part: one for ANSI, one for ITU-T. In this case, a single user part/application may associate itself with both NSAPs for that service, or separate user part/applications may be used for each protocol variant.

5.2 The MTP Configuration

The SS7 distribution software contains two MTP utility programs - mtp3cfg and mtp2cfg - which read a text configuration file and downloads the specified configuration to the MTP task on the TX board, typically as part of the download sequence.

The general format of the MTP configuration file is shown below:

<General Configuration Parameters>
END
<Link 0 definition>
<Layer 3 Parameters>
<Layer 2 Parameters>
END
<Link (n - 1) definition>
<Layer 3 Parameters>
<Layer 2 Parameters>
END
<NSAP 0 definition>
<NSAP Parameters>
END
<NSAP (n - 1) definition>
<NSAP Parameters>
END
<Route 0 definition>
<Route Parameters>
END
<Route (n - 1) definition>
<Route Parameters>
END
<Link Set 1 definition>
<Link Set Parameters>
END
<Link Set n definition>
<Link Set Parameters>
END

Use of the mtp3cfg utility is required for specifying the MTP layer 3 configuration. Use of the mtp2cfg utility is optional. It scans only the links definition section of the MTP configuration file and need only be run if it is necessary to override the default MTP layer 2 parameters assigned to each link (the default values for the MTP layer 2 parameters are specified in Section 5.5). The sample ss7load script, provided with the distribution software, executes both MTP configuration utilities.

5.2.1 General Configuration Section

The general configuration parameters define and control the general operation of the signaling point (SP) implemented by the TX SS7 software. General configuration parameters include the type of signaling point being constructed (SP or STP), the point code assigned to the signaling point, the MTP 3 timer resolution, the values for various SP-level timers, and the maximum number of other configurable elements (user parts (NSAPs), links, link sets, routes) to control memory allocation. The general parameters are configured once at board download time, before any other entities are configured. The board must be re-downloaded to change any of the general configuration parameters.

5.2.2 Links Configuration Section

The links configuration section defines the physical signaling links between the TX board and the adjacent signaling points. It contains a link configuration block for each SS7 link. The links section is scanned by both the MTP layer 3 and MTP layer 2 configuration utilities (this is the only section scanned by the MTP layer 2 configuration utility). Each link configuration block is comprised of both layer 3 parameters and layer 2 parameters, in any order.

The layer 3 configurable attributes of a link include the link number, the port and port type (serial or TDM) assigned to a link, the point code of the adjacent signaling point, protocol variant employed on the link (ITU-T or ANSI), point code length, maximum packet length, various timer values, membership in a linkset, and others.

The layer 2 configurable attributes include all layer 2 timers, the LSSU length to be used on the link, and the interface type - DCE or DTE - and baud rate for V.35 serial links.

5.2.3 Network Service Access Points (NSAPs) Section

Network service access points (NSAPs) define the SS7 user parts, or applications, which are users of the MTP service. The configurable attributes of NSAPs include the protocol variant (ITU-T or ANSI) and point code length supported by the user part/application associated with the NSAP, and the maximum number of user part/application messages to be queued (at each of the four possible message priority levels) when flow control between the MTP 3 and application is in effect.

5.2.4 Route Definition Section

Routes specify the destination signaling points (or sub-networks, for example, clusters when route masks are employed) that are accessible from the node being configured. Each route is assigned a direction - up or down. Up routes are used to identify incoming messages that are to be routed up to the applications/user parts. One down route is required for each remote signaling point/network/cluster that is to be accessible from the SP being configured. Down routes are used to route outgoing messages to the appropriate signaling links.

Other configurable attributes of routes include the destination point code, the protocol variant in use at the destination SP/cluster/network, and various timers associated with MTP route management.

5.2.5 Linkset Definition Section

The linkset configuration section contains a configuration block defining each linkset between the TX board and the adjacent signaling points. Linksets are numbered from 1 to MAX_LINKSETS (MAX_LINKSETS is a general configuration section parameter). The configurable attributes of a linkset include the point code of the adjacent signaling point, the list of routes that are accessible via that linkset, and the number of links to attempt to keep active.

5.3 Sample MTP Configuration File

The SS7 distribution software contains MTP sample configuration files for both ANSI and ITU-T configurations. The sample ANSI configuration for board one in the two-board sample test configuration appears as follows:

#------------------------------------------------
# Overall MTP3 Parameters
#------------------------------------------------
NODE_TYPE          STP        # choose STP [routing] or SP [non-routing]
PC_FORMAT          DFLT       # Point code format:  DFLT (8.8.8) / INTL (3.8.3) / JNTT (7.4.5)
POINT_CODE         1.1.1
RESTART_REQUIRED   TRUE
VALIDATE_SSF       FALSE
MAX_LINKS          4
MAX_USERS          2          # sccp & isup
MAX_ROUTES         64
MAX_ROUTE_ENTRIES  32
MAX_LINK_SETS      2
MAX_ROUTE_MASKS    1
ROUTE_MASK         0xFFFFFFFF
END
#
#------------------------------------------------
# Link Parameters
#------------------------------------------------
LINK               0          #  Link number specified in MTPMGR commands
PORT               T1         #  T<n> for T1/E1/MVIP, S<n> for serial (V.35), R for remote
LINK_SET           1
LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
ADJACENT_DPC       1.1.2      #  Board 2
LINK_SLC           0
LSSU_LEN           2
SSF                NATIONAL   # NATIONAL / INTERNATIONAL
END
#
# Sample Serial (V.35) configuration
#
#LINK               S1         #  T<n> for T1/E1/MVIP, S<n> for serial (V.35)
#LINK_SET           1
#LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
#ADJACENT_DPC       1.1.2      #  Board 2
#LINK_SLC           0
#LSSU_LEN           2
#SSF                NATIONAL   # NATIONAL / INTERNATIONAL
#INT_TYPE           DCE
#BAUD               56000
#END
#
#------------------------------------------------
# User Parameters (NSAP definition)
#------------------------------------------------
NSAP               0          # isup must be NSAP 0 if its present
LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
END
#
NSAP               1          # sccp can be 0 or 1, must be 1 if isup present
LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
END
#
#------------------------------------------------
# Routing Parameters
#------------------------------------------------
#
# Route UP from network to applications on this node
#
ROUTE              0
DPC                1.1.1      # this node
LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
DIRECTION          UP         # default is DOWN
ADJACENT_ROUTE     FALSE
END
#
# Route to board 2
#
ROUTE              1
DPC                1.1.2      # board 2's point code
LINK_TYPE          ANSI       #  ANSI / ITU / JNTT
END
#
#
#------------------------------------------------
# Linkset Parameters
#------------------------------------------------
LINK_SET_DESCRIPTOR       1
ADJACENT_DPC              1.1.2       # link set to board 2
MAX_ACTIVE_LINKS          4
ROUTE_NUMBER              1
END
#

5.4 MTP Configuration Considerations

The MTP 3 layer can be configured as either a signal transfer point (STP) or as a signaling end point, referred to simply as an SP. The primary difference between STP operation and SP operation is in the handling of messages received from signaling links by the MTP 3 layer but addressed to other destinations.

When configured as an STP, the MTP 3 layer will search for an outbound route to the message's destination and, if found, will route the message over an outbound link. When configured as an SP, the MTP 3 layer will discard such messages.

When configured as an STP, the MTP 3 layer will also perform the additional signaling route management procedures required of an STP. These primarily involve notifying adjacent SPs when they must no longer route messages to a particular destination through that STP due to failures or congestion (transfer prohibited/restricted), and notifying them again when normal communication with the concerned destination is restored (transfer allowed).

5.4.1 Configuring Routes to Non-Adjacent Nodes

The sample configuration shown above involves only a single adjacent signaling point directly connected to the TX board. You may also need to configure non-adjacent signaling points (for example, those that are not directly connected to the MTP 3 layer but are accessible through a signaling point that is directly connected), such as in the network configuration shown in Figure 4. The procedure for configuring a non-adjacent signaling point is as follows:

1. Configure all links, link sets, and routes to adjacent signaling points, such as the STPs in Figure 4, as described in the sample configuration files.

2. Add a route entry (direction down) for the non-adjacent SP, specifying its point code as the destination of the route.

3. Add the route number for the non-adjacent SP to the link set entry for each link set that may be used to reach the non-adjacent destination.
   
   
   Figure 4. Non-Adjacent Signaling Point

Since the non-adjacent SP in Figure 4 (point code 1.1.200) is accessible from both STPs the route entry for 1.1.200 is added to the link set definitions for both linksets one and two. Note that since the STPs in Figure 4 are cross-connected, the route to each STP is also added to both linksets one and two since STP 1.1.1 may be reached directly through linkset two or indirectly through linkset one via STP 1.1.0. A sample MTP configuration file for this network configuration appears as follows:

<General Parameters>
#
#Link Parameters
#
LINK                      T1       # Link 0 to STP 1.1.0
LINK_SET                  1
ADJACENT_DPC              1.1.0      
END
#
LINK                      T1       # Link 1 to STP 1.1.1
LINK_SET                  2
ADJACENT_DPC              1.1.1      
END
#
#Routing Parameters
#
# Route UP from network to applications on this node
#
ROUTE                     0
DPC                       1.1.100  # this node
DIRECTION                 UP
END
#
ROUTE                     1
DPC                       1.1.0    # STP 1.1.0
END
#
ROUTE                     2
DPC                       1.1.1    # STP 1.1.1
END
#
ROUTE                     3
DPC                       1.1.200  # Route to non-adjacent 1.1.200
END
#
# Link set Parameters
#
LINK_SET_DESCRIPTOR       1
ADJACENT_DPC              1.1.0    # link set to STP 1.1.0
ROUTE_NUMBER              1
ROUTE_NUMBER              2
ROUTE_NUMBER              3
END 
#
LINK_SET_DESCRIPTOR       2
ADJACENT_DPC              1.1.1    # link set to STP 1.1.1
ROUTE_NUMBER              1
ROUTE_NUMBER              2
ROUTE_NUMBER              3
END 

5.4.2 Using Priorities

Priority levels range from 0 (highest) to 15 (lowest). If priorities are used, you must start with zero for the highest priority linkset for a given route and thereafter increment by one for lower priority linksets for that route. There cannot be any gaps in the priority assigned for a given route, although equal priorities are allowed.

Linkset priorities can be used to assure that the shortest path will be taken by a message, when available. Using Figure 2 as an example, we would want messages destined for STP 1.1.0 to use linkset one (when available) and not linkset two, which would require an extra hop through STP 1.1.1. Similarly, for messages to STP 1.1.1 we would always want to use linkset two, if available.

To assure that linkset one will always be chosen for messages to STP 1.1.0, if available, we can assign a higher priority to route one in linkset one. Likewise, we can do the same for STP 1.1.1, route two, and linkset two. Linkset priorities are defined in the configuration file by placing a comma and the priority after a route number in the linkset definition.

Note: Route number one (STP 1.1.0) is assigned priority zero in linkset one and priority one in linkset two, indicating linkset one is higher priority than linkset two for messages destined for STP 1.1.0. Route number two
(STP 1.1.1) is assigned the reverse priorities. Routes three and four have no priorities assigned to them, indicating both linksets are of equal priority for reaching SP 1.1.200 and SP 1.1.201. When a priority is not specified, the default of zero (highest) is assigned. Therefore specifying 3,0 and 4,0 in both linksets would have the same results as not specifying a priority level at all. They are configured as equal priority because no matter which linkset is chosen, a message to either 1.1.200 or 1.1.201 will require two hops.

The following configuration excerpt shows how to specify linkset priorities for Figure 2:

#
# Routing Parameters
#
ROUTE           0
DPC             1.1.100      # this node
DIRECTION       UP
END
#
ROUTE           1
DPC             1.1.0        # STP 1.1.0
END
#
ROUTE           2
DPC             1.1.1        # STP 1.1.1
END
#
ROUTE           3
DPC             1.1.200      # SP 1.1.200
ADJACENT_ROUTE  FALSE        # Route to non-adjacent SP 1.1.200
END
#
ROUTE           4
DPC             1.1.201      # STP 1.1.201
ADJACENT_ROUTE  FALSE        # Route to non-adjacent SP 1.1.201
END
#
# Link Set Parameters
#
LINK_SET_DESCRIPTOR  1
ADJACENT_DPC         1.1.0
ROUTE_NUMBER         1,0
ROUTE_NUMBER         2,1
ROUTE_NUMBER         3
ROUTE_NUMBER         4
END

LINK_SET_DESCRIPTOR  2
ADJACENT_DPC         1.1.1
ROUTE_NUMBER         1,1
ROUTE_NUMBER         2,0
ROUTE_NUMBER         3
ROUTE_NUMBER         4
END

5.4.3 Using Routing Masks

The MTP 3 layer allows for the use of routing masks to help decrease the size of the routing tables that must be configured. Routing masks are bit masks that specify a subset of a destination point code to be matched against the routing table when searching for a route for either an inbound or outbound message.

Routing masks may be used to implement network and cluster routing in ANSI networks. For example, consider the following network diagram (Figure 5). Rather than specifying explicit routes to each of the seven remote SPs, routing masks and routes can be used (note that all point codes and routing masks, regardless of point code length, are stored internally as 32-bit unsigned integers). Routing masks are also useful when implementing server-type applications, such as Service Control Points (SCPs), where it is impractical to pre-configure the point codes of all possible requester signaling points.

Note: Routing masks are global to all links, link sets, and user parts, and are applied to both incoming and outgoing messages.

Figure 5. Using Routing Masks for Simpler Route Tables

Typical routing masks used in ANSI networks for routing based on Network and/or Cluster IDs are shown in the table below.

Note: Routing masks are applied to a message in the order that they appear in the MTP configuration file and the first matching mask/route is the one selected.

Routing Mask	Comment
0xFFFFFFFF	Always specify exact match as first mask
0xFFFFFF00	Match on network ID + cluster ID next
0xFFFF0000	Match on just network ID last

The following example shows a partial MTP configuration file for the network diagram provided earlier:

MAX_ROUTE_MASKS          3
ROUTE_MASK               0xFFFFFFFF     # always specify exact match 1st
ROUTE_MASK               0xFFFFFF00     # cluster mask next
ROUTE_MASK               0xFFFF0000     # network mask next
<Link Parameters>
#Routing Parameters
ROUTE                    0
DPC                      1.1.100        # Route up to this node
DIRECTION                UP 
END
#
ROUTE                    1
DPC                      1.1.255        # Explicit route to STP 1.1.255
END
#
ROUTE                    2
DPC                      1.2.255       # Explicit route to STP 1.2.255
END
#
ROUTE                    3
DPC                      2.1.255       # Explicit route to STP 2.1.255
END
#
ROUTE                    4
DPC                      1.1.0         # Partial route to cluster 1.1.x
END
#
ROUTE                    5
DPC                      1.2.0         # Partial route to cluster 1.2.x
END
#
ROUTE                    6
DPC                      2.0.0         # Partial route to network 2.x.y
END
# Link set Parameters
LINK_SET_DESCRIPTOR      1
ADJACENT_DPC             1.1.255       # link set to STP 1.1.255
ROUTE_NUMBER             1             # explicit route to 1.1.255
ROUTE_NUMBER             4             # cluster route to 1.1.x
END 
#
LINK_SET_DESCRIPTOR      2
ADJACENT_DPC             1.2.255       # link set to STP 1.2.255
ROUTE_NUMBER             2             # explicit route to 1.2.255
ROUTE_NUMBER             5             # cluster route to 1.2.x
END 
#
LINK_SET_DESCRIPTOR      3
ADJACENT_DPC             2.1.255   # link set to STP 2.1.255
ROUTE_NUMBER             3         # explicit route to 2.1.255
ROUTE_NUMBER             6         # network route to 2.x.y
END 
#

Although the previous example is specific to ANSI networks, routing masks can be applied equally to other networks (ITU-T based networks with 14- or 24-bit point codes) to reduce the size of routing tables.

When using routing masks and "partial-match" routes, the following guidelines should be adhered to.

• Always configure an UP route with the TX board's point code first.

• Always configure an explicit route to each node directly connected to the TX board.

• Always configure an "exact match" routing mask - 0xffffffff - before any "partial match" routing masks.

5.4.4 Considerations for Configuring for Japan-NTT Protocol Variant

The following guidelines should be followed when configuring the MTP layer for Japan-NTT network operation.

1. The LINK_TYPE attribute for all links, NSAPs, and route entries should be set to JNTT.

2. The point code length for links and NSAPs will default to 16 once the LINK_TYPE is set to JNTT; there is no need to specify this explicitly. If desired for documentation purposes, however, the point code length can be explicitly set to 16 (the only supported value for JNTT link type) in the link and NSAP configurations.

3. 16-bit point codes may be specified in either hex or in "x.y.z" dotted notation. Hex point codes must be specified in the same order that they are transmitted on the link; that is, the U-code in the most significant seven bits, the S-code in the next four bits, and the M-code in the least significant five bits. In order to specify J-NTT 16-bit point codes in "x.y.z" notation, the PC_FORMAT parameter in the MTP 3 general configuration section must be set to the value JNTT.
   For example:

             PC_FORMAT     JNTT
             ...
             LINK          S1
             LINK_TYPE     JNTT
             ADJACENT_DPC  1.1.2
             ...
   
   

   Is equivalent to:

             ...
             LINK          S1
             LINK_TYPE     JNTT
             ADJACENT_DPC  0x421
             ...
   

5.4.5 Sample MTP Configuration File for Japan-NTT Protocol Variant

A sample MTP3 configuration file for two V.35 serial links with the JNTT protocol variant is shown below.

#-----------------------------------------------------
# Sample MTP3 configuration for J-NTT protocol variant
#-----------------------------------------------------
#Overall MTP3 Parameters
#-----------------------
#
NODE_TYPE          SP           # choose STP [routing] or SP [non-routing]
PC_FORMAT          JNTT
POINT_CODE         1.1.1
RESTART_REQUIRED   FALSE
MAX_LINKS          4
MAX_USERS          2            # isup + 1 extra
MAX_ROUTES         64
MAX_ROUTE_ENTRIES  32
MAX_LINK_SETS      2
MAX_ROUTE_MASKS    1
ROUTE_MASK         0xFFFFFFFF
END
#
#Link Parameters
#---------------
#
# Link 0
#
LINK               S1           # Serial port 1
LINK_SET           1
LINK_TYPE          JNTT
ADJACENT_DPC       1.1.2
LINK_SLC           0
LSSU_LEN           1
INT_TYPE           DCE
BAUD               56000
END
#
# Link 1
#
LINK               S2           # Serial port 2 (V.35)
LINK_SET           1
LINK_TYPE          JNTT
ADJACENT_DPC       1.1.2
LINK_SLC           1
LSSU_LEN           1
INT_TYPE           DCE
BAUD               56000
END
#
#User Parameters (NSAP definition)
#---------------------------------
#
NSAP               0           # isup 
LINK_TYPE          JNTT
END
#
NSAP               1           # spare
LINK_TYPE          JNTT
END
#
#
#Routing Parameters
#------------------
#
# Route UP from network to applications on this node
#
ROUTE              0
LINK_TYPE          JNTT
DPC                 1.1.1       # this node
DIRECTION          UP          # default is DOWN
ADJACENT_ROUTE     FALSE
END
#
# Route to Adjacent node
#
ROUTE              1
LINK_TYPE          JNTT
DPC                1.1.2
END
#
#
# Linkset Parameters
#-------------------
LINK_SET_DESCRIPTOR 1
ADJACENT_DPC        1.1.2
MAX_ACTIVE_LINKS    4
ROUTE_NUMBER        1
END
#

5.5 MTP Configuration Parameters Reference

There are five major sections of the MTP configuration file - general parameters, link parameters, network SAP parameters, routing parameters, and link-set parameters.

5.5.1 General Parameters

The following table lists all configurable parameters in the MTP 3 general configuration section and their default values. The default values for all timers at the MTP 3 level are in tenths of a second. A configuration value of zero for a timer disables that timer. The MTP3_TIMER_RES parameter may be used to specify whether timer values being overridden in the MTP 3 configuration file are specified in seconds or tenths of a second.

Note: The PC_FORMAT attribute applies to all point codes throughout the entire MTP configuration file.

Parameter Name	Default	Range	Usage
PC_FORMAT	DEFAULT	DEFAULT [DFLT], INTER-NATIONAL [INTL], JNTT	Point Codes are interpreted/displayed as 24-bit 8.8.8 values. Point Codes are interpreted/displayed as 14-bit 3.8.3 values. Point codes are interpreted/displayed as 16-bit mcode.scode.ucode values with the U-code in the most significant 7 bits, the S-code in the next 4 bits, and the M-code in the least significant 5 bits.
POINT_CODE	none	N/A	The Point Code of this node, specified in dot notation (such as 2.45.76) or a hex number (such as 0x101). This is a required parameter.
NODE_TYPE	STP	STP | SP	Selects STP [routing] or SP [non-routing] mode of operation.
POINT_CODE2		N/A	Alternate point code for this node when interfacing to both ANSI and ITU-T networks from same board (in that case, specify the ITU-T point code in POINT_CODE parameter and ANSI point code here).
MTP3_TIMER_RES	SECONDS	TENTHS, SECONDS	Specifies whether timer values in the configuration file are in seconds or tenths of a second.
RESTART_REQUIRED	TRUE	TRUE / YES FALSE / NO	Set to TRUE if full restart procedure required whenever node becomes accessible.
VALIDATE_SSF	TRUE	TRUE / YES FALSE / NO	When set to true, MTP 3 will validate incoming MTP 3 signaling network management (SNM) and test (SLTM/SLTA) messages; i.e., those whose SSF does not match the value configured for the link the message was received on will be rejected; otherwise the SSF will not be checked on incoming MTP 3 management or test messages - any SSF value will be accepted. MTP 3 will not validate the SSF in any incoming or outgoing user part messages.
DISABLE_UPU	FALSE	TRUE/YES FALSE/NO	If set to TRUE, MTP will never send a User Part Unavailable message.
MAX_LINKS	4	1 to 16	Maximum number of physical links (actual maximum depends on TX board model and hardware configuration).
MAX_USERS	2	1 to 64	Maximum number of MTP 3 users (user parts).
MAX_ROUTES	32	1 to 32767	Maximum number of routes.
MAX_ROUTE_ENTRIES	64	1 to 32767	Maximum number of route instances (logical max is MAX_LINKS * MAX_ROUTES, but can be decreased).
MAX_LINK_SETS	1	1 to 16	Maximum number of link sets supported.
MAX_ROUTE_MASKS	0	0 to 8	Maximum number of routing masks. If zero, then all destination point code in outgoing messages must exactly match a point code in a route entry.
ROUTE_MASK	None	0x00 to 0xFFFFFFFF	A routing mask to be applied to destination point code before matching against route table entries. Can be used to reduce number of routes that must be configured or when remote destination point codes are not known at configuration time (that is, a database server). Multiple ROUTE_MASKs may be specified; they are applied in the order that they appear in the configuration file.
TIMER_T15	30	0 to 65535	Wait to start/repeat route set congestion test.
TIMER_T16	20	0 to 65535	Wait for route set congestion status update.
TIMER_T18_ITU	300	1 to 65535	ITU restart timer for an STP during which links are restarted and TFA, TFR, and TFP messages are received.
TIMER_T20_ITU	600	1 to 65535	ITU overall restart timer.
TIMER_T22_ANSI	300	1 to 65535	ANSI restart timer at restarting SP waiting for links to become available.
TIMER_T23_ANSI	300	1 to 65535	ANSI restart timer at restarting SP waiting for TRA messages.
TIMER_T26_ANSI	130	1 to 65535	ANSI restart timer at restarting SP waiting to repeat TRW message.
TIMER_T27_ANSI	30	1 to 65535	Minimum duration of unavailability for full restart.
TIMER_TRTEINST	300	0 to 65535	Internal route instance timer (how long a route instance is valid) - NOT ANSI T30.
MTP3_TRACE_DATA	FALSE	TRUE, FALSE	TRUE starts tracing of all data between MTP 2 and MTP 3.
END	N/A	N/A	Marks the end of the general parameters section.

5.5.2 Link Parameters

The following tables specify the configuration parameters applicable to each link. The first table lists the layer 3 parameters and the second table lists the layer 2 parameters.

MTP 3 Link Parameters

MTP 2 Link Parameters

All layer 2 times are specified in tenths of seconds (e.g. 60 = 6 seconds).

MTP 2 Parameter	Default	Range	Description
ERR_TYPE	NORMAL	NORMAL, PCR	Error correction method: Normal or Preventive Cyclic Retransmission.
L2_T1	130 (ANSI) 400 (ITU-T)	1 to 65535	Timer aligned/ready.
L2_T2	115 (ANSI) 100 (ITU-T)	1 to 65535	Timer not aligned.
L2_T3	115 (ANSI) 15 (ITU-T)	1 to 65535	Timer aligned.
L2_T4_N	23 (ANSI) 82 (ITU-T)	1 to 65535	Normal proving period.
L2_T4_E	6 (ANSI) 5 (ITU-T)	1 to 65535	Emergency proving period.
L2_T5	1	1 to 65535	Timer sending SIB.
L2_T6	60	1 to 65535	Timer remote congestion.
L2_T7	20	1 to 65535	Timer excessive delay of acknowledgement.
L2_T10	30	1 to 65535	Amount of time MTP 2 can be isolated from a remote MTP 3 before sending processor outage (SIPO).
L2_T11	20	1 to 65535	Time to wait for a flow control acknowledgement from MTP 3 before sending another flow control indication.
L2_T12	20	1 to 65535	Time to wait for a status confirmation from MTP 3 before sending another status indication.
L2_T13	20	1 to 65535	Time to wait for a disconnect confirmation from MTP 3 before sending another disconnect indication.
LSSU_LEN	2	1 to 2	LSSU length.
MAX_FRAME	272	64 to 1024	Maximum frame length for MSU.
SUERM_THRESH	64	1 to 255	Signal unit error rate monitor threshold (bad frames).
SUERM_D_RATE	256	1 to 65535	Signal unit error rate monitor decrement rate (frames).
AERM_THRESH_E	1	1 to 255	Alignment error rate monitor error rate threshold (emergency alignment).
AERM_THRESH_N	4	1 to 255	Alignment error rate monitor error rate threshold (normal alignment).
MAX_RTB_MSGS	127	1 to 255	Maximum number of MSUs for retransmission (when using PCR error correction only).
MAX_RTB_OCTETS	34544	1 to 65535	Maximum number of MSUs octets for retransmission (when using PCR error correction only).
MAX_PROV_ABORT	5	1 to 255	Maximum # of proving failures.
BAUD	56000	4800, 9600, 19200, 28800, 38400, 48000, 56000, 64000	Baud rate for serial ports only (in bits per second).
INT_TYPE	DTE	DTE | DCE	Interface type for serial ports only.
DATA_ENC	NRZ	NRZ | NRZI	Data encoding (NRZ or NRZ inverted).
SHARE_FLAGS	TRUE	TRUE | FALSE	Allow single flag to be shared between frames.
USE_FLAGS	TRUE	TRUE | FALSE	Use flags (TRUE) or idles (FALSE) between frames.
MIN_FLAGS	0	0 to 15	Minimum number of additional flags between frames (in addition to shared flag).
ISO_THRESH	1000	1 to 65535	Number of messages queued to MTP 3 while isolated that will cause MTP 2 to begin processor outage (SIPOs).
L2_TXQ_THRESH1	50	1 to 65535	Transmission queue length at which the outbound flow control level is raised to one.
L2_TXQ_THRESH1_A	20	1 to 65535	Transmission queue length at which the outbound flow control level is lowered to zero.
L2_TXQ_THRESH2	200	1 to 65535	Transmission queue length at which the outbound flow control level is raised to two. The subsequent indication causes MTP 3 to cease all transmission to MTP 2 until the flow control level returns to one or zero.
L2_TXQ_THRESH2_A	100	1 to 65535	Transmission queue length at which the outbound flow control level is lowered to one.
L2_SAP_THRESH	500	1 to 65535	Number of messages queued to MTP 3 while inbound flow control is in effect that will cause MTP 2 to send busy indications (SIBs).
L2_SAP_THRESH_A	100	1 to 65535	Number of messages queued to MTP 3 while inbound flow control is in effect that will cause MTP 2 to stop sending busy indications (SIBs).
IDLE_FREQ	0	1 to 65535	Frequency at which FISUs are sent by the software (in ms). Zero indicates that hardware constantly retransmits duplicate FISUs as is the norm. Non-zero frequencies can be used by switches that process all FISUs (including duplicate FISUs) in the software.
RT_FREQ	0	1 to 65535	Frequency at which other retransmitted SUs (specifically LSSUs) are sent by the software (in ms). Zero indicates that hardware constantly retransmits duplicate LSSUs as is the norm. Non-zero frequencies can be used by switches which process all LSSU's (including duplicate LSSUs) in the software.

5.5.3 Network Service Access Point (NSAP) Parameters

The following parameters are used for defining an NSAP (the service access point for MTP 3 by an upper layer task):

Parameter Name	Default	Range	Usage
NSAP	none	0 to (MAX_USERS-1)	The NSAP number. REQUIRED.
LINK_TYPE	ANSI	ANSI ITU JNTT	MTP 3 protocol variant used by this MTP 3 user part.
P0QUE_LENGTH	0	2 to 1024	Receive queue length threshold at which the congestion priority is raised to level 0.
P1QUE_LENGTH	512	(p0Qlen + 2) to 1024	Receive queue length threshold at which the congestion priority is raised to level 1.
P2QUE_LENGTH	768	(p1Qlen + 2) to 1024	Receive queue length threshold at which the congestion priority is raised to level 2.
P3QUE_LENGTH	896	(p2Qlen + 2) to 1024	Receive queue length threshold at which the congestion priority is raised to level 3.
DISCARD_PRIORITY	0	0 to 3	The congestion priority at which messages with priority below the current threshold are discarded rather than being queued and risking further congestion escalation.
DPC_LENGTH	24 (ANSI) 14 (ITU-T) 16 (JNTT)	14 | 16 | 24	Number of bits in a point code, must be either 14, 16, or 24. A DPC_LENGTH value of 16 is only valid on links whose LINK_TYPE is JNTT.
END			Marks end of this NSAP definition.

5.5.4 Routing Parameters

The following table lists all configurable parameters for a MTP 3 route entry.

Parameter Name	Default	Range	Usage
ROUTE	none	0 to MAX_ROUTES	Route identifier number, from 0 to MAX_ROUTES-1. REQUIRED.
DPC	none	N/A	The point code that's the target of the route entry. Use dot format (such as 2.45.76) or a hex number (such as 0x101).
SPTYPE	STP	SP | STP	Type of signaling point the destination is, SP or STP.
LINK_TYPE	ANSI	ANSI, ITU JNTT	MTP 3 protocol variant associated with this route.
SSF	NATIONAL (ANSI), INTER-NATIONAL (ITU-T)	NATIONAL, INTER-NATIONAL	Value for the sub-service field to be used in route management messages for this route.
SUB_SERVICE	2	0 to 3	Overrides SSF parameter. Use either SUB_SERVICE or the SSF parameter, but not both.
DIRECTION	DOWN	UP | DOWN	Route direction. UP routes result in messages being routed to user parts or applications on this node; DOWN routes are routes to remote signaling points.
ADJACENT_ROUTE	TRUE	TRUE | YES FALSE | NO	Indicates whether this is a route to an adjacent signaling point (a signaling point that is directly connected to this node) - used only if this node is configured for STP operation.
ADJACENT_CLUSTER	FALSE	TRUE | YES FALSE | NO	Indicates whether this is a route to an adjacent cluster, allowing use of the cluster variant of route management messages (ANSI only).
TIMER_T8	10	0 to 65535	Transfer Prohibited inhibition timer.
TIMER_T10	450	0 to 65535	Wait to start/repeat periodic route set test.
TIMER_T19_ITU	680	1 to 65535	ITU restart timer to avoid ping-pong of TFP, TFR, or TRA messages.
TIMER_T21_ITU	640	1 to 65535	Overall ITU restart timer at adjacent SP.
TIMER_T25_ANSI	320	1 to 65535	ANSI restart timer at adjacent SP waiting for a TRA message.
TIMER_T28_ANSI	300	1 to 65535	ANSI restart timer at adjacent SP waiting for a TRW message.
TIMER_T29_ANSI	630	1 to 65535	ANSI restart timer started when a TRA is sent in response to an unexpected TRA or TRW.
TIMER_T30_ANSI	320	1 to 65535	ANSI restart timer to limit sending of TFPs and TFRs in response to unexpected TRA or TRW.
END			Marks end of this route definition.

5.5.5 Link Set Parameters

The following parameters are valid for defining a link set:

Parameter Name	Default	Range	Usage
LINK_SET_DESCRIPTOR	none	1 to MAX_LINKSETS	The Link Set identifier number; referenced in LINK_SET parameter of each individual link.
ADJACENT_DPC	none	N/A	The point of the adjacent SP that terminates this link set. Use "dotted" notation, 2.45.76 or hex number, 0x101.
MAX_ACTIVE_LINKS	16	1 to 16	Target number of links in this link set to keep active at any given time.
ROUTE_NUMBER	none (priority for a route defaults to zero)	0 to MAX_ROUTES	A route number and optional priority associated with a destination that can be reached through this link set; up to 16 route numbers may be specified per link set. The same route number may be assigned to multiple link sets. The optional priority associated with the route number is relative to other link sets which also contain this route number.
END			Marks end of this Link Set definition.