Adjusting the Load Among M3UA or MTP3 Signaling Links
Scenarios
Impact on the System
Prerequisites
Workflow
Procedure
Verification
Example 1
Example 2
Example 3
Additional Information
Scenarios
If the load is not balanced among the link sets or links destined for the same DSP, the load must bemodified.
Impact on the System
This operation has no adverse impact on the system.
Prerequisites
Conditions
Run LST N7DSP and LST N7LKS, and check whether the link selection mask of the SS7 links or thelink set selection mask of the SS7 link sets is correct. For more information about the mask selectionprinciple, see Related concepts.
Data
Data preparation is not required for this operation.
Workflow
Check the peer device for an unbalanced load if the measurement data shows that the sendload of each link is balanced (that is, each link sends a similar number of messages inbytes), but the received load is not balanced.
Add links if the load is balanced among links but the load exceeds the rated value.
If the load is not balanced, adjust the load among links by running the command in thefollowing table.
Procedure
1. Check whether the number of links is to the power of 2.
Yes: Go to 3.
No: Add new links to ensure that the number of links is to the power of 2. Fordetails, see Adding M2UA Links.
2. Check whether the load among the links is balanced.
a. For MTP3 link sets only, run the following command:
MOD N7DSP: DPNM=DSP name, SLSSM=Linkset selection mask;
b. For M3UA link sets only, run the following command:
MOD M3DE: DENM=Destination entity name, SLSSM=Linkset selectionmask;
NOTE:For more information about how to determine the parameter SLSSM, see Related concepts.
4. Modify the link selection mask.
For MTP3 link sets only, run the following command:
MOD N7LKS: LSNM=Linkset name, SLSM=Link selection mask;
For M3UA link sets only, run the following command:
MOD M3LKS: LSNM=Linkset name, SLSM=Link selection mask;
NOTE:For more information about how to determine the parameter SLSM, see Related concepts.
Verification
Check Point Check Item Status Remarks
Sending load sharingof the signaling links
Bytes of sent Messages Balance Create the performancemeasurement for theM3UA or MTP3 signalinglink
Receiving loadsharing of thesignaling links
Bytes of receivedMessages
Balance
Example 1
Task Description
The following example scripts are provided to show how to adjust the load by configuring the linkselection masks.
Scripts
1. Configure the link set selection mask based on the number of link sets destined for the sameDSP. Change the link set selection mask of the link set destined for the HLR to 0001,because there are two link sets between the MSOFTX3000 and the HLR.
For MTP3 links:
M O D N 7 D S P : D P N M = " t o H L R " , S L S S M = B 0 0 0 1 ;
For M3UA links:
M O D M 3 D E : D E N M = " t o H L R " , S L S S M = B 0 0 0 1 ;
NOTE:
The link set selection mask is determined by the number of link sets destined forthe same DSP. If there are two link sets destined for the same DSP, the numberof 1s in the mask is 1.
2. Configure the link selection mask based on the number of links. There are eight links in eachlink set. Change the link selection mask of the links destined for the HLR to 1110.
M O D N 7 L K S : L S N M = " t o H L R " , S L S M = B 1 1 1 0 ;
For M3UA links:
M O D M 3 L K S : L S N M = " t o H L R " , S L S M = B 1 1 1 0 ;
NOTE:
There are eight links in each link set. Therefore, the number of 1s in the linkselection mask is 3 (2 3̂=8). In addition, the lowest bit of the link set selectionmask is 1. Therefore, the link selection mask is 1110. Configure the link selectionmasks in the same way for both link sets.
Example 2
Task Description
There are 12 MTP3 links configured between the home location register (HLR) and the peer office. Amongthese links, four links share twice the load of the other eight links.
The link selection mask of the MTP3 link set is B1111.
Analysis
The link selection mask is correct.
The link selection mask allows up to 16 links in the MTP3 link set. In that case, there are 16 tokensdefined for the 12 links distribution. The four links that are distributed with the extra four tokens sharetwice the load of the other links.
Solution
Add four MTP3 links to the MTP3 link set.
Suggestion
To balance the load sharing, the number of links in a link set should be to the power of 2, such as 2, 4, 8,or 16.
Example 3
Task Description
There are two M3UA links configured between the MSOFTX3000 and the HLR. The load of one link is10% higher than the load of the other link.
The link set selection mask is B0001.
The link selection mask is B1000.
Analysis
The link set and the link selection masks are correct.
The performance measurement data shows that Receive Seizure Ratio of the two signaling links arethe same, but Send Seizure Ratio of one signaling link is 10% higher than that of another signaling link.This indicates that the configuration of the link load sharing on the HLR is not appropriate.
Solution
Modify the HLR M3UA links configuration.
Suggestion
Use Send Seizure Ratio or the Receive Seizure Ratio to analyze the sending or receiving loadsharing.
Additional Information
Related Tasks
1. Based on the performance measurement data of the links or link sets, do the following:
Check whether the load is balanced among all links destined for the same DSP.
Identify the links or link sets on which the load is not balanced.
To create the measurement tasks, choose Traffic over MTP3 Signaling Link Sets andTraffic over MTP3 Signaling Links, or Traffic over M3UA Signaling Link Sets andTraffic over M3UA Signaling Links under Signaling and Interface in the MSOFTX3000performance management system.
Typically, if the difference of the load on different link sets or links exceeds 10%, the load isnot balanced.
Related Concepts
The load sharing is adjusted by configuring the link selection mask. The mask configuration principles areas follows:
1. The link set selection mask of a link set is related to the maximum number of link sets overthe routes that are destined for the same signaling point and have the same priority. Thenumber of link sets determines the number of 1s in the link set selection mask, as shown inthe following table.
Table 1 Mapping between the number of link sets and the number of 1s in the link setselection mask
Number of Link Sets Number of 1s in the Link Set Selection Mask
1 0
2 1
3 - 4 2
5 - 8 3
9 - 16 4
2. The link selection mask is related to the number of links in the link set. The number of linksdetermines the number of 1s in the link selection mask, as shown in the following table.
Table 2 Mapping between the number of links and the number of 1s in the link selectionmask
Number of Links Number of 1s in the Link Selection Mask
1 0
2 1
3 - 4 2
5 - 8 3
9 - 16 4
3. The signaling link selection code (SLS) has the same function in the selection of thesignaling links and signaling link sets. Therefore, to ensure that all links in a link set can beselected, the bit value 1 in the link selection mask and the bit value 1 in the link set selectionmask cannot be in the same position. For example, if the link set mask is 0011 and thenumber of signaling links is 4, the link selection mask must be 1100. If the number ofsignaling links is 2, the link selection mask must be 1000 or 0100.
4. The SLS in TUP/ISUP messages is determined by the four least significant bits of the CircuitIdentification Code (CIC), and controlling/non-controlling mode is adopted by trunk circuits.Therefore, the CIC in TUP/ISUP messages transferred after a call is originated in the localoffice is an even number (the controlling circuit in local office with CIC of an even number) oran odd number (the controlling circuit in local office with CIC of an odd number). Accordingly,
the SLS is an odd number or an even number, namely, the SLS is not evenly distributed inthe lowest bit. Therefore, for signaling links and signaling routes that are used to transferTUP/ISUP messages, the mask with the lowest bit of 1 (XXX1) should be avoided.
If the link selection mask and the link set selection mask are not configured in compliance with thepreceding principles, modify the configuration.
1. If there is only one MTP3/M3UA link set between the MSOFTX3000 and the DSP, and theload is not balanced among links in the link set, configure the link and link set selectionmasks as follows:
Set the link set selection mask to the default value.
If only one signaling link is configured in a link set, set the link selection maskset to the default value.
If two or more signaling links are configured in a link set, ensure that the decimalvalue of the link selection mask is equal to or greater than the total number oflinks minus 1. For example, if there are only two links in a link set, do not set thelink selection mask to B0000.
To prevent overlapping of bits, do not set the link set selection mask and the linkselection mask of any link set to the same value. It is recommended to set 1 inthe two masks in different positions. For example, if the link set selection maskis 0110, the link selection mask can be set to 1001.
If bit 6 of software parameter 11 is set to 1 (default value), bit 1 to bit 4 of the CICare used as the SLS of the ISUP and BICC messages, thus implementing theoptimized link load balancing function. If bit 6 of software parameter 11 is set to0, bit 0 to bit 3 of the CIC are used as the SLS of the ISUP and BICC messagesbased on the recommendations of the protocol.
2. If there are two or more MTP3/M3UA link sets between the MSOFTX3000 and the DSP andthe load is not balanced among link sets, configure the link and link set selection masks asfollows:
Ensure that the decimal value of the link set selection mask is equal to or greaterthan the total number of link sets minus 1. For example, if there are a total of twolink sets, do not set the link set selection mask to B0000.
To prevent overlapping of bits, do not set the link set selection mask and the linkselection mask of any link set to the same value. it is recommended to set 1 inthe two masks in different positions. For example, if the link set selection maskis 0110, the link selection mask can be set to 1001.
