Global title translation

Tip

Any number of attributes (gtencoding, trtype, natofaddr, numplan) can be left empty to match any value in a GT. More specific rules, defining specific attribute values, are matched first.

To create a rule matching all GTs, also set is-prefix = true, and leave addrinfo empty.

To configure GT translation, see the following sections:

Note
Atribute modification restrictions

  • Only attributes that are "Reconfigurable" can be modified after a configuration object is created.

  • Attributes that do not support "Active Reconfiguration" can be changed only when the configuration object is disabled (the value of its disabled attribute is false).

Incoming GT translation

Use the following attributes to configure GT translation for incoming SCCP messages. Whenever the incoming called address for an SCCP message is a GT, it is matched against this configuration to determine whether it should be accepted and, optionally, which SSN should receive it.

inbound-gtt

Attribute name Attribute description Default Modification

oname

object name

dependencies

number of items which depend on this object

Read-only

trtype

translation type

Attribute optional; when unspecified matches ANY value

Reconfigurable

numplan

numbering plan

Attribute optional; when unspecified matches ANY value

Reconfigurable

natofaddr

nature of address

Attribute optional; when unspecified matches ANY value

Reconfigurable

addrinfo

address string

Attribute optional; when unspecified and is-prefix is true, matches ANY value

Reconfigurable

is-prefix

specifies if address string contains prefix

false

Reconfigurable

ssn

local SSN that handles the traffic

Attribute optional; when unspecified the SSN from the Called Party Address will be used

Reconfigurable
Note The JMX Object name for inbound-gtt is SGC:type=sccp,category=inbound-gtt.

Outgoing GT translation

GT translation configuration used for outgoing SCCP messages. Whenever the outgoing SCCP message called address is a GT, it is matched against this configuration to derive the destination PC and optionally SSN. After translation SCCP message called address may be modified according to the replace-gt configuration.

outbound-gt

Use the following attributes to configure GT translation in an outgoing direction. An outgoing SCCP message that contains a GT in the called address parameter will be matched against the outbound-gt definitions.

Attribute name Attribute description Default Modification

oname

object name

dependencies

number of items which depend on this object

Read-only

trtype

translation type

Attribute optional; when unspecified matches ANY value

Reconfigurable

numplan

numbering plan

Attribute optional; when unspecified matches ANY value

Reconfigurable

natofaddr

nature of address

Attribute optional; when unspecified matches ANY value

Reconfigurable

addrinfo

address string

Attribute optional; when unspecified and is-prefix is true matches ANY value

Reconfigurable

is-prefix

specifies if the address string contains a prefix

false

Reconfigurable
Note The JMX Object name for outbound-gt is SGC:type=sccp,category=outbound-gt.

outbound-gtt

Use these attributes to represent a Destination Point Code where the SCCP message with a matching GT (referenced through the gt attribute) will be sent.

Tip

Multiple outbound-gt definitions can reference a single outbound GT. In such cases, a load-balancing procedure is invoked.
Attribute name Attribute description Default Modification

oname

object name

dependencies

number of items which depend on this object

Read-only

gt

reference to O-GT

Reconfigurable

dpc

destination point code; a 14-bit integer;
supported formats: simple integer (4106) or int(3bit)-int(8bit)-int(3bit) (2-1-2)

Reconfigurable

replace-gt

reference to replace-gt

Reconfigurable

priority

priority of this translation (larger value is higher priority)

Reconfigurable
Note The JMX Object name for outbound-gtt is SGC:type=sccp,category=outbound-gtt.

replace-gt

These attributes may be used to modify the SCCP message’s called address parameter, after a matching GT is found through the use of outbound-gt and outbound-gtt.

Attribute name Attribute description Default Modification

oname

object name

dependencies

number of items which depend on this object

Read-only

route-on

what will be inserted in the SCCP called address; allowed values are:

  • SSN — route on SSN; include translation-derived DPC

  • GT — route on GT

  • RI — leave intact.

RI

Reconfigurable

gtencoding

new encoding of the address

Attribute optional

Reconfigurable

trtype

new translation type

Attribute optional

Reconfigurable

numplan

new numbering plan

Attribute optional

Reconfigurable

natofaddr

new nature of address

Attribute optional

Reconfigurable

addrinfo

new address string in hex/bcd format

Attribute optional

Reconfigurable

ssn

specify new SSN to add to GT

Attribute optional

Reconfigurable

gti

new global title indicator; allowed values are: 0 (no GT), 1, 2, 3, or 4

Attribute optional

Reconfigurable
Note The JMX Object name for replace-gt is SGC:type=sccp,category=replace-gt.

Concerned Point Codes

cpc

CPC configuration stores information about remote SCCP nodes that should be informed about the local subsystem availability state.

Attribute name Attribute description Default Modification

oname

object name

dependencies

number of items which depend on this object

Read-only

dpc

concerned point code which is notified about status changes; a 14-bit integer;
supported formats: simple integer (4106) or int(3bit)-int(8bit)-int(3bit) (2-1-2)
Note The JMX Object name for cpc is SGC:type=sccp,category=cpc.

Load balancing

Global Title translation may be used to provide load balancing and high availability functions. If there is more than one outbound-gtt referencing a single outbound-gt, the SCCP layer is responsible for routing the message to one of the vailable SCCP nodes (destination point codes). If the SCCP message is a subsequent message in stream class 1 (sequenced connectionless) and the previously selected SCCP node (PC) is still reachable, then that previously used PC is selected. If there is any other message for which GT translation results in multiple reachable point codes, messages are load balanced among the available PCs with highest priority.

The pseudo-algorithm is:

  1. outbound-gtts referencing the same GT (outbound-gt) are grouped according to their priority (larger value is higher priority).

  2. Unreachable PCs are filtered out.

  3. If there is more than one PC of highest priority, then messages are load balanced using a round robin algorithm between those PCs.

Whenever the prefer-local attribute of outbound-gtt is set to value true, routes local to the node are used in that algorithm (if such routes are currently available; otherwise prefer-local is ignored). Routes local to the node are those that are available through an SCTP association that was established by that particular node.

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