Oracle Communications Diameter Signaling Router (DSR)
 

PLA-Support>Sun Systems>CommsGBU>Global Signaling Solutions>SN-SND: Tekelec DSR
 

In this Document

Goal

Solution

References

Created from <SR 3-14932006671>

Applies to:

Goal

There are parameters in Diameter Common -> MPs -> Profiles that we are allowed to change. But we cannot actually figure out how do they work. They are:

• CL1 Discard Percent (%)
• CL2 Discard Percent (%)
• CL3 Discard Percent (%)
• DOC Message Discard Percentage (%)

We Know which CPU load levels correspond to Danger of Congestion (DoC), CL1, CL2, CL3 (they are set in IDB table SysMetricThreshold). And parameters in question determine how many messages are shed at each level.

This document explains how message drop amount depends on this parameters (how DSR acts at each load level depending on them)? 

Solution

The DA-MP capacity values are dependent on the DA-MP hardware and hosted application on the system.

Two important discard rates mentioned below are calculated using the CLx, DA-MP Engineered MPS, DA-MP Maximum Ingress MPS, DoC Disc %

1. D-TRDR DA-MP Danger of Congestion Target Request Discard Rate
2. 2. C-TRDR DA-MP Congestion Target Request Discard Rate

For example if DA-MP is in DoC; D-TRDR is calculated as:

(DAMP-Offered-MPS – DAMP-Engineered-MPS) * DOC-Discard-Percent

Similarly; If the DA-MP is in Lvl1/Lvl2/Lvl3 Congestion:

C-TRDR = (DAMP-MPS – DAMP-Engineered-MPS ) + ( DAMP-Engineered-MPS * CL1 or CL2 or CL3-Discard-Percent)

If Ingress Message Rate presented to Overload Control exceeds “DA-MP Maximum Ingress MPS”, then CSL shall calculate TDR based upon the following equation:

TDR = DA-MP Offered-MPS – DA-MP Maximum Ingress MPS

Hence a DoC set at 20% does not mean that 20% of the messages will be discarded or a CL1 set at 0% does not mean that no messages will be discarded when reaching CL1. However; these values will be used to calculate the actual message discard rate using above formulae during a certain interval.

Important values to consider:

• DA-MP Maximum Ingress MPS / MP Engineered Maximum Ingress MPS:
• An Engineering configurable ingress MPS limit which dictates the maximum rate at which the DA-MP will process messages from all connections.
• Any messages which exceed this rate are discarded except “inviolable” messages
• This value may be greater than the MP Engineered Ingress MPS.

MP Engineered Ingress MPS / MpEngingressMPS depends upon Hardware and Application. Hardware + Application identify which DA-MP Profile Type will be used e.g. a G8 Server Running Database will have G8/G9: Database profile whose MpEngIngressMPS is set to be 40,000. G8/G9 running Relay application will have MpEngIngressMPS will be 45000.

DA-MP Maximum Ingress Ingress MPS is configured in DA-MP Profile. For Example:

• For a G7 Server with Database profile;
• MpMaxingressMps = 100000
• MpEngIngressMps = 40000

MPEngIngressMPS is helpful in determining upper cap for Total Reserved Ingress MPS of all Diameter Connections. For example:

• 10 connections: All with Reserved Ingress MPS of 500 = Total Reserved Ingress MPS of 5000
• This value 5000 cannot exceed MPEngIngressMPS relevant to DA-MP profile.

So on Connection basis:

• Reserved Ingress MPS (i.e. MPS values reserved specifically for a certain connection. others will not be able to use this reserved value.)
• Configured Max Ingress MPS (i.e. a connection's maximum limit of Ingress MPS.)

Total Configured Max Ingress MPS can be more than MPEngIngressMPS but that does not mean system will be able to handle that traffic.

System will determine its system wide parameters (MPEngIngressMPS & DA-MP Max Ingress MPS) to identify how much total traffic it can carry.

References

This solution has no attachment