(Page 1 of 1 in this chapter)

Chapter 5

SS7 MTP Configuration

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 Link Set 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 Routing Masks
5.4.3 Considerations for Configuring for Japan-NTT Protocol Variant
5.4.4 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
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 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 TX Series 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 signalling links, routes, link sets, and Network Service Access Points (NSAPs).

Links define physical signaling links between the TX Series 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 (see below) 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 - e.g., 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 link set that can be used to reach that destination. Each link set within the route's associated combined link set 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.

Figure 2 illustrates the relationship between links, link sets, 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 below illustrates the concept of NSAPs.

Figure 3. Network Service Access Points (NSAPs)



If multiple protocol variants are configured on the same MTP3 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 CD 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 Series 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 5.4).  The sample SS7LOAD script provided on the distribution CD 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 Series 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 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 Series 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 first link defined in the MTP configuration file is always link 0; the second is always link 1, and so on.



The layer 3 configurable attributes of a link include 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 link set (see below) 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 MTP3 and application is in effect.  






5.2.4	 Route Definition Section





Routes specify the destination signaling points (or sub-networks - e.g., 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	 Link Set Definition Section





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


 






5.3	 Sample MTP Configuration File





The SS7 distribution CD contains MTP sample configuration files for both ANSI and  ITU-T configurations.  The sample ANSI configuration for board 1 in the 2-board sample test configuration is shown below.


#Overall MTP3 Parameters
NODE_TYPE                 SP          # choose STP or SP [non-routing]
POINT_CODE                1.1.1
RESTART_REQUIRED          TRUE
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                      T1          #  T<n> for TDM, S<n> for 
                                      # serial (V.35)
LINK_SET                  1
ADJACENT_DPC              1.1.2       #  Board 2
LINK_SLC                  0
MAX_CREDIT                127
MESSAGE_SIZE              272
#
# Level 2 parameters
#
LSSU_LEN                  2
END
#
#User Parameters (NSAP definition)
#
NSAP                      0           # isup must be NSAP 0 if its 
                                      # present
END
#
NSAP                      1           # sccp must not be 0 if isup 
                                      # present
END
#Routing Parameters
#
# Route UP from network to applications on this node
#
ROUTE                     0
DPC                       1.1.1       # this node
DIRECTION                  UP         # default is DOWN
ADJACENT_ROUTE             FALSE
END
#
# Route to board 2
#
ROUTE                      1
DPC                        1.1.2      # board 2's point code
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 TX Series MTP3 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 MTP3 layer but addressed to other destinations.  



When configured as an STP, the TX Series MTP 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 MTP3 layer will discard such messages.



When configured as an STP, the TX Series MTP 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 Series board.  You may also need to configure non-adjacent signaling points - i.e., those that are not directly connected to the TX series MTP 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 above 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 STP's the route entry for 1.1.200 is added to the link set definitions for both link sets 1 and 2.  Note that since the STP's in Figure 4 are cross-connected, the route to each STP is also added to both link sets 1 and 2 since STP 1.1.1 may be reached directly through link set 2 or indirectly through link set 1 via STP 1.1.0.  A sample MTP configuration file for this network configuration is shown below:


<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 Routing Masks





The TX Series MTP3 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 7 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 shown above:


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 above 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.






5.4.3	 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 7 bits, the S-code in the next 4 bits, and the M-code in the least significant 5 bits. In order to specify J-NTT 16 bit point codes in "x.y.z" notation, the PC_FORMAT parameter in the MTP3 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
              ...    

 
    







5.4.4	 Sample MTP Configuration File for Japan-NTT Protocol Variant





A sample MTP3 configuration file for 2 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 MTP3 general configuration section and their default values.  The values for all timers at the MTP3 level are in seconds.  A configuration value of zero for a timer disables that timer.


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 "<M-Code>.<S-Code>.<U-Code>" 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 as "dotted" notation, e.g., 2.45.76 or a hex number, e.g., 0x101. REQUIRED.




 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).




 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, MTP3 will validate


 incoming MTP3 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 MTP3 management or test messages - any SSF value will be accepted. MTP3 will not validate the SSF in any incoming or outgoing user part messages.




 MAX_LINKS



 4



 1..16



 Maximum number of physical links (actual maximum depends on TX Series board model and hardware configuration)




 MAX_USERS



 2



 1..64



 Maximum number of MTP3 users (user parts)




 MAX_ROUTES



 32



 1..32767



 Maximum number of routes




 MAX_ROUTE_ENTRIES



 64



 1..32767



 Maximum number of route instances (logical max is MAX_LINKS * MAX_ROUTES, but can be decreased)




 MAX_LINK_SETS



 1



 1..16



 Maximum number of link sets supported




 MAX_ROUTE_MASKS



 0



 0..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 - 


 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 (e.g., a database server).


 Multiple ROUTE_MASKs may be specified; they are applied in the order that they appear in the configuration file.




 TIMER_T15



 3



 0..65535



 Wait to start/repeat route set congestion test 




 TIMER_T16



 2



 0..65535



 Wait for route set congestion status update




 TIMER_T18



 2



 0..65535



 Timer at restarting SP waiting for links to become available (ANSI T22 Value)




 TIMER_T19



 5



 0..65535



 Timer at restarting SP waiting to receive all traffic restart allowed (ANSI T23 Value)




 TIMER_T20



 4



 0..65535



 Timer at restarting SP waiting to broadcast traffic restart allowed messages (ANSI T24 Value)




 TIMER_T21



 5



 0..65535



 Wait to restart traffic routed through adjacent restarting SP (ANSI T28 Value)




 TIMER_T26



 14



 0..65535



 Timer at restarting SP waiting to repeat traffic restart waiting message




 TIMER_T29



 60



 0..65535



 Wait when TRA sent in response to unexpected TRA or TRW




 TIMER_T30



 30



 0..65535



 Internal route instance timer (how long a route instance  is valid) - NOT ANSI T30.




 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.


 MTP3 Link Parameters


  





 MTP3 Parameter



 Default



 Range



 Usage




 LINK



 none



 S1..4 (serial)
T1..16 (TDM)



 T<n> for T1/E1/MVIP, S<n> for serial (V.35). 




 LINK_TYPE



 ANSI



 ANSI
ANSI88
CCITT | ITU
JNTT



 MTP3 protocol variant used on link




 ADJACENT_DPC



 none



 N/A



 The point code of the node on the other end  of the link.  Use "dotted" notation, e.g., 2.45.76 or hex number, e.g., 0x101.  




 LINK_SET



 1



 1..16



 The link set this link belongs to.




 SSF



 NATIONAL (ANSI),
INTER-NATIONAL
(ITU-T)



 NATIONAL,
INTER-NATIONAL



 The value used in the sub-service field (SSF) of the SIO.




 SUB_SERVICE



 2



 0..3



 Overrides SSF parameter. Use either SUB_SERVICE or the SSF parameter, but not both.




 LINK_PRIORITY



 0



 0..3



 Priority of this link within the link set.  Priorities range from 0 [highest] to 3 [lowest]




 MESSAGE_SIZE



 272



 64..1024



 Maximum message length for this link




 DISABLED



 FALSE



 TRUE / FALSE



 If false, link will is initially enabled, i.e. it tries to align with the remote side immediately. If true, link is initially disabled, i.e. no attempt to align with remote side is made.




 USE_PRIORITY



 TRUE



 TRUE | FALSE



 If true, message priorities generated by user parts are inserted into the SIO octet ("spare bits") of outgoing messages; otherwise, the SIO "spare bits" are set to zero.  This is usually set to TRUE in ANSI networks and FALSE in ITU-T networks.




 MGNT_MSG_PRIORITY



 3



 0..3



 Priority to use for MTP3 management messages (3 = highest, 0 = lowest)




 DPC_LENGTH



 24 (ANSI) 
14 (CCITT)
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.




 MAX_SLTM_RETRY



 2



 0..255



 Maximum times to retry SLTM




 P0QUE_LENGTH



 16



 2..1024



 Transmit queue length threshold at which the congestion priority is raised to level 0.




 P1QUE_LENGTH



 32



 (p0Qlen + 2) ..1024



 Transmit queue length threshold at which the congestion priority is raised to level 1.




 P2QUE_LENGTH



 64



 (p1Qlen + 2) ..1024



 Transmit queue length threshold at which the congestion priority is raised to level 2




 P3QUE_LENGTH



 128



 (p2Qlen + 2) ..1024



 Transmit queue length threshold at which the congestion priority is raised to level 3




 DISCARD_PRIORITY



 0



 0..3



 The congestion priority at which messages with priority below the current threshold are discarded rather than being queued and risking further congestion escalation.




 LINK_SLC



 0



 0..15



 Link selection code for signaling link testing




 LINK_TEST_PATTERN



 "TST"



 1-15 ASCII Characters



 Link test pattern for SLTM messages




 TIMER_T1



 1



 0..65535



 Delay to avoid message mis-sequencing on changeover




 TIMER_T2



 1



 0..65535



 Wait for changeover acknowledgment




 TIMER_T3



 1



 0..65535



 Time controlled diversion  - delay to avoid mis-sequencing on changeback




 TIMER_T4



 1



 0..65535



 Wait for first changeback acknowledgment (1st attempt)




 TIMER_T5



 1



 0..65535



 Wait for first changeback acknowledgment (2nd attempt)




 TIMER_T6



 1



 0..65535



 Delay for avoid mis-sequencing on controlled rerouting




 TIMER_T7



 2



 0..65535



 Wait for data link connection acknowledgment




 TIMER_T11



 60



 0..65535



 Transfer Restricted timer




 TIMER_T12



 6



 0..65535



 Wait for uninhibit acknowledgment




 TIMER_T13



 1



 0..65535



 Wait for forced uninhibit




 TIMER_T14



 3



 0..65535



 Wait for inhibition acknowledgment




 TIMER_T17



 1



 0..65535



 Delay to avoid oscillation of initial alignment failure and link restart




 TIMER_T22



 110



 0..65535



 Wait to repeat local inhibit test (ANSI T20 Value)




 TIMER_T23



 110



 0..65535



 Wait to repeat remote inhibit test (ANSI T21 Value)




 TIMER_T24



 4



 0..65535



 Reserved for future use (NOT ANSI T24) 




 TIMER_T31



 5



 0..65535



 Internal BSN Requested Timer  (NOT ANSI T31)




 TIMER_T32



 10



 0..65535



 Wait for response to SLTM timer (ANSI T1.111.7 timer T1 - NOT ANSI T32)




 TIMER_T33



 20



 0..65535



 Signaling link connection timer (NOT ANSI T33)




 TIMER_T34



 60



 0..65535



 Periodic signaling link test timer   (ANSI T1.111.7 timer T2 - NOT ANSI T34)




 END



 N/A



 N/A



 Marks end of this link definition















 


 MTP2 Link Parameters





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

  





 MTP2 Parameter 



 Default 



 Range



 Description




 ERR_TYPE



 NORMAL



 NORMAL,
PCR



 Error correction method: Normal or Preventive Cyclic Retransmission (PCR not fully supported). 




 L2_T1



 130 (ANSI)
400 (ITU-T)



 1..65535



 Timer "aligned/ready"




 L2_T2



 115 (ANSI)
100 (ITU-T)



 1..65535



 Timer "not aligned"




 L2_T3



 115 (ANSI)
15 (ITU-T)



 1..65535



 Timer "aligned"




 L2_T5



 1 



 1..65535



 Timer "sending SIB"




 L2_T6



 60 



 1..65535



 Timer "remote congestion"




 L2_T7



 20 



 1..65535



 Timer "excessive delay of acknowledgement




 L2_T4_N



 23 (ANSI)
82 (ITU-T)



 1..65535



 Normal proving period




 L2_T4_E



 6 (ANSI)
5 (ITU-T)



 1..65535



 Emergency proving period




 LSSU_LEN



 2



 1..2



 LSSU length




 MAX_FRAME



 272



 64..1024



 Maximum frame length for MSU




 SUERM_THRESH



 64



 1..255



 Signal unit error rate monitor threshold (bad frames)




 SUERM_D_RATE



 256



 1..65535



 Signal unit error rate monitor decrement rate (frames)




 AERM_THRESH_E



 1



 1..255



 Alignment error rate monitor error rate threshold (emergency alignment)




 AERM_THRESH_N



 4



 1..255



 Alignment error rate monitor error rate threshold (normal alignment)




 MAX_RTB_MSGS



 30



 1..255



 Max # of MSUs for retransmission (when using PCR error correction only)




 MAX_RTB_OCTETS



 220



 1..65535



 Max # of MSUs octets for retransmission (when using PCR error correction only)




 MAX_PROV_ABORT



 5



 1..255



 Maximum # of proving failures




 BAUD



 56000



 4800, 9600, 19200, 28800, 38400, 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..15



 Minimum number of additional flags between frames (in addition to shared flag)















 






5.5.3	 Network Service Access Point (NSAP) Parameters





The following parameters are used for defining an NSAP (the service access point for MTP3 by an upper layer task):


  





 Parameter Name



 Default



 Range



 Usage




 NSAP



 none



 0.. MAX_USERS-1



 The NSAP number.  REQUIRED.




 LINK_TYPE



 ANSI



 ANSI
ANSI88
CCITT | ITU
JNTT



 MTP3 protocol variant used by this MTP3 user part.




 P0QUE_LENGTH



 8



 2..1024



 Receive queue length threshold at which the congestion priority is raised to level 0




 P1QUE_LENGTH



 16



 (p0Qlen + 2) ..1024



 Receive queue length threshold at which the congestion priority is raised to level 1




 P2QUE_LENGTH



 32



 (p1Qlen + 2) ..1024



 Receive queue length threshold at which the congestion priority is raised to level 2




 P3QUE_LENGTH



 64



 (p2Qlen + 2) ..1024



 Receive queue length threshold at which the congestion priority is raised to level 3




 DISCARD_PRIORITY



 0



 0..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 MTP3 route entry.


  





 Parameter Name



 Default



 Range



 Usage




 ROUTE



 none



 0..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 "dotted" notation, e.g., 2.45.76 or hex number, e.g., 0x101.




 SPTYPE



 STP



 SP | STP



 Type of  signaling point the destination is, SP or STP




 LINK_TYPE



 ANSI



 ANSI, 
ANSI88,
CCITT | ITU
JNTT



 MTP3 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.




 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 (i.e., 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



 1



 0..65535



 Transfer Prohibited inhibition timer




 TIMER_T10



 45



 0..65535



 Wait to start/repeat periodic route set test




 TIMER_T21



 5



 0..65535



 Wait to restart traffic routed to adjacent restarting SP (ANSI T28 Value)




 TIMER_T25



 30



 0..65535



 Wait for traffic restart allowed message from adjacent restarting SP




 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..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, e.g., 2.45.76 or hex number, e.g., 0x101.




 MAX_ACTIVE_LINKS



 16



 1..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..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.
























 
    (Page 1 of 1 in this chapter)




 




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