05_ load balancer

1 © Nokia Siemens Networks CN60024EN50GLA0

Loadbalancer in SR5.0 H248 Loadbalancer FN1840

SIP Loadbalancer FN1828

M3UA Loadbalancer FN1949

IPDU based M3UA Loadbalancer FN1949


Objective

Describe the main functions of the different Loadbalancer feature.

Show the differences between the implementations at DX, IPA and ATCA Platform

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H248 Loadbalancer

H.248 Load Balancer FN1840 available for

• MSS DX200 in M14.6 (SR4.0) and for

• Open MSS in Ma16.1(SR5.0)

• Feature code 1424 in MGW

Load Balancer for SIP FN 1828 available for


• Open MSS in Ma16.1 (SR5.0)

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Challenge: • Currently a SCTP association is created from each MSS signaling unit to each ISU unit in

MGW

• The MGW is divided to as many virtual MGWs as there are ISUs which creates more complicated configuration

Solution: • With Load Balancer for H.248 the SCTP associations between MSS and MGW are

centralized to specific units in networks elements

• The Load Balancer unit uses the H.248 signaling units in MSS and MGW as a resource pool

Load Balancer for H.248

• Improved IP address management enables easier network planning and configuration

• Free configuration of virtual MGW concept allows the physical MGW to be configured even

as one virtual MGW => Larger TDM circuit groups (CGR) enables better utilization of TDM

links

• Greatly simplified network architecture

Operator benefits

SR5.0

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Functionality:

• Only two redundant IP addresses visible outside the network

elements for H.248 traffic using SCTP multihoming

• Flexible configuration of virtual MGWs within one physical

MGW

• Multiple ISU units can be part of single virtual MGW

• Flexible expansion of MSS and MGW signaling unit capacity

• IPDU unit in MSS and MISU (Master ISU) unit in MGW are

responsible of internal load balancing

• Note: H.248 Load Balancer for MSS DX200 available in

M14.6 (SR4.0) and for MSS ATCA in Ma16.1(SR5.0)

Support required (e2e viewpoint):

• L3 connectivity and Ethernet based Message Bus (EMB)

required in MSS

• L3 not required in MGW

Load Balancer for H.248

GISU GISU GISU

MSS

SISU SISU SISU

MGW

IPDU

MISU MISU

IPDU

GISU GISU GISU

MSS

ISU ISU ISU

MGW

SR5.0

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H.248 load balancer

The feature is used in order to minimize the number of virtual MGWs within a single physical MGW. Load balancing in this case, means that the number of H.248 interfaces required will be reduced by introducing H.248 unit pool that control single MGWs through a single H.248 interface connection.

SCTP associations are terminated to the IP Director Units (IPDU), which are located in MSS cabinets (in same physical slots as SIGUs or other signaling units). IPDUs have internal SCTP associations towards individual SIGU units. The number of SIGUs within a single pool can be from one to multiple tens of SIGUs.

In the MSS, a new Linux-based IPDU computer unit is used. It is recommended that the same IPDUs are used for both H.248 and SIP load balancers. Thus, more resilience is gained with fewer IPDUs.

H.248 load balancer have the following benefits:

fewer IP addresses are used

more simple connectivity configuration process

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Introduction

Overview on H.248 load balancing options in the IPA2800 MGW and DX200 MSS.

Three different H.248 load balancing options are introduced. Some recommendations and

examples are given to clarify how different options affects to HW and signaling link

configurations between MSS and MGW. Options are:

1) H.248 Load Balancing in MSS and MGW (SR4.0 system feature)

• Concurrent H.248 load balancing implementation to MSS and MGW

• ISU/SIGU load balancing, less IP addresses for H.248 links, less vMGW, etc…

2) H.248 load balancing in MGW by ISU’s full mesh configuration

• All ISUs becomes an Master ISU and Slave ISU

• H.248 load is shared among all ISUs regardless of vMGW – ISU configuration

• Fast and easy feature activation (no changes at MSS)

3) H.248 Load Balancer in MGW

• ISUs are configured to have either Master ISU or Slave ISU functions

• H.248 load is shared among all Slave ISUs

• Feature activation is moderate easy in MGW but requires some changes to

controlling MSS(s)

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Options

MSS

MSS

MGW

MGW

SIGU SIGU SIGU

MISU

SISU SISU

ISU ISU ISU

H.2

48

H.2

48

H.2

48

SIGU SIGU SIGU

ISU ISU ISU

IPDU

H.2

48

1.) H.248 Load Balancing

in the MSS and MGW

MSS

MSS

MGW

MGW

SIGU SIGU SIGU

MISU

SISU SISU

ISU ISU ISU

H.2

48

H.2

48

H.2

48

SIGU SIGU SIGU

ISU ISU ISU

H.248

3.) H.248 Load Balancer in

the MGW

MSS

MGW

SIGU SIGU SIGU

MISU

SISU

MISU

SISU

MISU

SISU

ISU ISU ISU

H.2

48

H.2

48

H.2

48

MSS

MGW

H.2

48

H.2

48

H.2

48

SIGU SIGU SIGU

ISU ISU ISU

2.) H.248 load balancing in

MGW by a ISU full mesh

configuration

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Impact to MGW

• H.248 LB introduces two new logical entities to ISU:

• Master ISU (MISU); have the H.248/SCTP associations with IPDUs, distributes

load to SISUs and holds the internal circuit groups (CGRs) data for the TDM

trunks.

• Slave ISU (SISU); process the H.248 messages, provides signaling gateway

(SGW) services and controls the SS7 links.

• Each Virtual MGW (VMGW) created belongs to some MISU

• MISU and SISU functions are configured to different physical ISUs.

MSS

MGW

SIGU SIGU SIGU

MISU

SISU SISU

ISU ISU ISU

IPDU

H.2

48

• MISU selects the least loaded SISU for a call context request

• MISU may handle a call context by itself in case its the least loaded ISU among the SISUs

and MISUs

• MISU may address a call context handling to another MISU instead of SISU

• Number of MISU per MGW is 2 or 4 depending on call attempt rate (“BHCA”)

• Number of VMGWs per MGW depends on how many IPDU units are connected to MISUs (minimum is one VMGW / MISU)

• One active IPDU is recommended to connect two MISUs (VMGWs)

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H.248 Load Balancing for Open MSS: two unit pools controlling four vMGWs on two pMGWs

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Requirements

Software

The feature can be used only with SCTP transport between the MSS and the MGW.

The SCTP streams used by this feature need to be supported from the MGW. MGWs can be connected to the MSS in the previous way and with the new unit pool concept (introduced with this feature) at the same time. However, a single MGW can only either be connected in the previous way or via unit pool.

In order to use the H.248 load balancing functionality, a U4.2 or higher release of the Multimedia Gateway (MGW) is required.

This is a licensed functionality. A license needs to be purchased before using it. Feature 1840: High Capacity Virtual MGW Support in MSS.

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Requirements

Hardware

• An IP Director Unit (IPDU) needs to be configured in the MSS.

• IPDU Linux units are needed in the MSS. The Load Balancer application (LB) runs in the IPDU computer unit. The minimum configuration is 1+1 IPDU units (one working unit, one spare unit) and the maximum configuration is 5+1 IPDU units.

• This feature requires L3 connectivity in the MSS.

• This feature requires an Ethernet Message Bus (EMB) in the MSS.

• Note: Number of IPDUs per MSS or GCS is 2–5 (+ one dedicated redundant unit)

• Capacity of one active IPDU is enough for the entire MSS/GCS but two active IPDUs are recommended (provides better service level during possible IPDU switchover to redundant unit)

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Requirements

• H.248 LB in MSS and MGW is a system feature of SR4.0 (M14.6 TOP SW + U5.0/U4.2 SW)

• Feature activation requires corresponding license to MSS&MGW (on/off type)

• MSS: “Load Balancer for H.248” (L4242/C4242)

• MGW: “MGW H.248 Load Balancing” (3GNLIC0056)

• IPDU function requires CPU variant CP816-A (or newer ) and EMB message bus in the MSS or GCS.

• Layer 3 (L3) IP connectivity for the control plane is mandatory in the MSS with H.248 LB feature (IPDU).

• ISU CPU type CCP10 is NOT accepted with system level H.248 LB.

• Following documents provides detailed information on feature and how it is configured to MSS and MGW

• Feature 1840: High Capacity Virtual MGW Support in MSC Server (MSS - DN0954599)

• Feature description, H.248 Load Balancing (MGW - DN0948169),

• Integrating MGW into MSC Server system (MGW - DN04163252),

• JV-Virtual Media Gateway handling (MGW - DN01192483) and

• JJ - Load Balancer Configuration Handling (MSS - DN0931259)

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H.248 Load Balancing by means of unit pools for Open MSS

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Overload control

With the help of the Overload control for Linux IPDU - SIP and H.248 load balancers functionality, MSS can limit H.248 traffic, so that IPDU does not become congested.

PRFILE parameter: H.248 LB: load balancer overload control

This parameter indicates whether the new OLC method (Window Access Control (WAC)) for H.248 load balancers is switched on.

The H.248 access gates should be on H.248 unit pool basis.

IPDUs could be set as protected unit.

ZWOI:12,125 PARAMETER NAME: H248LB_OLC_CONTROL

User: IPDU

Allowed values: False / True = Default

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Overload control - OLC

As the same IPDU can be used to transfer H.248, SIP, and all kinds of M3UA based signaling as well, it can happen that extensive call initiation rate is started when there is some catastrophe (flooding, earthquake, and so on).

It is important to cut new calls before they consume too much MSS and/or IPDU resources. The implemented OLC assumes that proper dimensioning is done. So OLC would not be needed on daily, weekly, or monthly basis, only at exceptional circumstances.

The selected OLC method for SIP and H.248 load balancers is the Window Access Control (WAC) method.

MSS opens the window access control (WAC) gate, which implements a token queue. In case of H.248 Load Balancer, when a call requires a new H.248 context, a token is reserved.

The following three priority levels are used in the token queue:

• priority call (highest priority level)

• emergency call

• other call (lowest priority)

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IP connectivity Virtual IP addresses are used for internal communication in the signaling

units which support this feature for the following reasons:

• Since this feature is optional, the use of virtual IP addresses makes the feature as transparent as possible to the external world.

• Virtual IP addresses in the signaling units provide a means for avoiding the routing of non-load-balanced traffic via the IPDU. That is, the traffic from an MGW is routed to the MSS external IP address (which is the IP address of the IPDUs). The IPDU forwards the SCTP packets to the appropriate GISUs based on their unit specific virtual IP addresses (which are stored in a unit pool database) using layer 2 routing.

In the other direction, H.248 traffic from the GISUs is destined to the IPDU by configuring a local IP address based default gateway.

The IP addressing mechanism for this feature comprises of the following:

• In each IPDU we need two virtual IP addresses for each H.248 pool, that is, one per SCTP path.

• We need one physical IP address for each GISU (including the spare unit).

• For internal backup data, every IPDU needs to have as many physical IP addresses as there are active IPDUs in the system.

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IP connectivity

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Restrictions

• TCP transport cannot be used between the MSS and the MGW when this feature is used.

• A GISU unit cannot handle both vMGWs via the IPDU unit (load balanced using the ‘unit pool’ concept) and vMGWs directly (the previous method used before the availability of this feature) at the same time.

• A GISU unit can belong to only one H.248 unit pool at a time.

• One IPDU unit can handle only one H.248 unit pool at a time.

• One H.248 unit pool can handle up to 30 vMGWs at a time.

• A maximum of five unit pools can be configured in the MSS with a maximum of 254 units in each.

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Media Gateway Data Handling, JG command group in MSS

JGC CREATE MGW

This command is used to create a new Media Gateway (MGW) entry in the MGW database. The following parameters are related to this feature:

• UPOOL

This is the ID of the unit pool to which the MGW is assigned. This

can be a decimal number ranging from 0 to 4 (since the MSS can

have a maximum of five unit pools configured).

• MODE

This parameter is used to specify the SCTP functionality to be used

by the MGW.

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MODE = enhanced SCTP mode The parameter is optional. It can be given only if TTY=SCTP. H248SCTP

• Standard H.248 SCTP functionality according to ITU-T H.248.1 and ITU-T H.248.4. – DEFAULT -

H248TCP

• SCTP functionality is enhanced with LONG-Timer and TransactionResponseAck functionality according to ITU-T H.248.1 Annex D.2.

HIDDENTCP

• SCTP functionality is enhanced with LONG-Timer usage according to ITU-T H.248.1 Annex D.2.

NOH248REQREP

• Standard H.248 SCTP functionality. TransactionRequest or TransactionReply is never re-sent by the H.248 application.

The functionality of SCTP mode configurability in the MGW database optimizes performance by preventing the execution of the same H.248 transaction multiple times.

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Media Gateway Data Handling, JG command group in MSS JGM MODIFY MGW

This command is used to modify entries in the MGW database. The following

parameters are related to this feature:

• MODCTRL | MODUPOOL

These parameters allow you to specify whether or not control unit

data is taken from the unit pool data. If MODCTRL is given, then the

UPOOL parameter cannot be set. If MODUPOOL is given, then the

type, index, and address of the control unit is filled from the unit pool

data.

• UPOOL

This is the ID of the unit pool to which the MGW is assigned.

• MODE

This parameter is used to specify the SCTP functionality (for

example, standard SCTP functionality or TCP-like functionality) to

be used by the MGW.

JGI INTERROGATE MGW

This command is used to obtain data from the MGW database. The following

new parameter is related to this feature:

• UPOOL

When this parameter is set with the ID of a unit pool, all MGWs

assigned to this unit pool are displayed in the printout.

JGO OUTPUT H.248 EVENT LOG DATA

This is a command introduced by this feature that can be used to output

the contents of the MSS H.248 event log buffer.

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Interrogate the MGWs which use the unit pool ID 1. ZJGI::UPOOL=1; MGW DATA:

MGW ID MGW NAME MGW TYPE CTRL UNIT POOL ID REG STATUS PARSET:USED/DEF NBCRCT MGW IP ADDRESS/DOMAIN NAME

21 MGW21 GENERAL CCSU 0 1 NOT REGISTERED -/0 0 1.2.3.21 22 MGW22 GENERAL CCSU 0 1 NOT REGISTERED -/0 0 1.2.3.22 23 MGW23 GENERAL CCSU 0 1 NOT REGISTERED -/0 0 1.2.3.23 COMMAND EXECUTED

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H.248 Unit Pool Handling, JE command group in MSS JEC CREATE UNIT POOL

This command is used to create an H.248 unit pool.

JEA ADD UNIT TO THE UNIT POOL

This command is used to add a SIGU/CCSU unit to an existing unit pool.

JEM MODIFY UNIT POOL DATA

This command is used to modify the configuration of an existing unit pool.

JER REMOVE UNIT FROM THE UNIT POOL

This command is used to remove a SIGU/CCSU unit from a unit pool.

JEI INTERROGATE UNIT POOL

This command is used to output configuration information about a unit

pool.

JEO DETAILED UNIT STATUS INTERROGATION

This command is used to interrogate the LBPSTA file content.

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ZJEI

POOL ID POOL NAME PRIM UNIT IPD UNIT SECUNSEL IPD IP ADDRESS

--------------------- ---------------------------------------------------------- 0 ALMA SIGU 3 IPDU 0 YES 10. 85. 20. 60 2 KORTE SIGU 0 IPDU 1 YES 10. 85. 20. 61 COMMAND EXECUTED

ZJEI::POOLID=2; UNIT POOL DATA ------------------------------------------------------------ UNIT POOL NAME : KORTE UNIT POOL ID : 2 IPD UNIT : IPDU 1 IPD IP ADDRESS : 10. 85. 20. 61 SEC UNIT SEL : YES SCTP PARAMETER SET NUMBER : 16 UNIT LIST: UNIT | ID | UNIT-ROLE | LB-ID | UNIT-INFO | IP ADDRESS - ------------------------------------------------------------ SIGU 0 PRIMARY 1 ACTIVE 172. 31. 4.251 SIGU 1 SECONDARY 2 ACTIVE 172. 31. 4.250 SIGU 2 ORDINARY 3 ACTIVE 172. 31. 4.252 COMMAND EXECUTED

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Load Balancer Parameter Handling, JJ command group in MSS

You can use the commands of this command group to configure the H.248 load balancer.

JJC CONFIGURE LOAD BALANCER

This command is used to create or modify the configuration of the IPDU,

such as defining internal and external interfaces and adding the H.248

load balancer application.

JJE CONFIGURE LOAD BALANCER PARAMETERS

This command can be used to specify the name of the load balancer

application to be used.

JJI INTERROGATE LOAD BALANCER CONFIGURATION

This command is used to obtain information about the configuration of

the IPDU and load balancer application.

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ZJJI:TYPE=UNIT:UTYPE=IPDU,;

IPD UNIT INFO INT EXT UNIT INDEX INTERFACE INTERFACE LBS NAME ---- ---- --------- --------- -------- IPDU 0 VLAN10 VLAN9 LBSSIP1 IPDU 1 VLAN10 VLAN9 IPDU 2 VLAN10 VLAN9 LBSSIP2 IPDU 3 VLAN10 BOND0 H248LBS1

ZJJI:TYPE=LBS:LTYPE=H248;

INTERROGATING LBS CONFIGURATION LBS CONFIGURATION LBS NAME ..................(NAME)... :LBSH248 LBS TYPE .............(TYPE)... :H.248 LBS STATE ........................ ........ :ACTIVE LBS CONFIGURATION LBS NAME ..................(NAME)... :H248LBS1 LBS TYPE ..........(TYPE)... :H.248 LBS STATE ................................ :ACTIVE

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PRFILE

PRFILE parameter: H.248 LB load difference threshold

This parameter indicates the size of the difference needed before last stored capacity

(=the one which is used in unit selection) and the capacity based on the current load indication

before recalculation takes place.

PARAMETER NAME: H248_LB_LOAD_DIFF_TRESH

Parameter class: 53

Parameter id: 64

User: URQ

Allowed values: 1-20

Increment: 1

Default value: 1

PRFILE parameter: H.248 LB regular load report threshold

This parameter indicates the limit above which URQ initiates a periodical update for the

unit.

PARAMETER NAME: H248_LB_REG_LOAD_REP_TH

Parameter class: 53

Parameter id: 65

User: URQ

Allowed values: 1-100

Increment: 1

Default value: 85(%)

PRFILE parameter: H.248 LB regular load report interval

This parameter indicates the time interval between periodical updates, that is, how often

URQ initiates periodical update for the unit.

PARAMETER NAME: H248_LB_REG_LOAD_REP_IV

Parameter class: 53

Parameter id: 66

User: URQ

Allowed values: any

Increment: 100 ms

Default value: 5000 ms

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PRFile

PRFILE parameter: EMB-sync reattempt timer

This parameter defines the length of time after the IPDU retries the EMB-based syncing

procedure when a previous attempt indicated that the xSU unit was not working.

PARAMETER NAME: H248_LB_EMB_SYNC_RETRY

Parameter class: 53

Parameter id: 71

User: IPDU

Allowed values: any

Increment: 100 ms


PRFILE parameter: Wait for internal HB acknowledgement timer

This parameter defines the length of time an IPDU should wait for an internal heartbeat

acknowledgement message without taking recovery actions.

PARAMETER NAME: H248_LB_INT_HB_ACK

Parameter class: 53

Parameter id: 69

User: IPDU

Allowed values: any

Increment: 100 ms


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MGW

SIGU – ISU configuration * without H.248 LB (only one MSS controlling MGW) 1/2

H.248 M3UA

IUA

Example MSS/MGW

configuration:

• 16 + 1 SIGUs

• 17 + 1 ISUs

SGW:

* IP/M3UA SS7/MTP3

* SS7 signaling link

processing

MSS/GCS

M3UA

H.248 SIGU0

H.248

vMGW

1

ISU1

ISU0

vMGW

2

ISU2

vMGW

3

ISU3

vMGW

4

ISU4

vMGW

5

ISU5

SIGU2

H.248 H.248

SIGU1

H.248

SIGU4

H.248

SIGU3

H.248

SIGU6

H.248

SIGU5

H.248

SIGU8

H.248

SIGU7

H.248

• 16 SIGUs connected to 17 ISUs • 17 VMGW configured into (one / ISU)

• SIGU #16 divided between two ISUs

• 17 H.248 links between SIGUs / ISUs

• TDM circuits connected to vMGW • One CGR / vMGW

• Max. 128 PCM / vMGW

vMGW

13

ISU13

vMGW

14

ISU14

vMGW

15

ISU15

vMGW

16

ISU16

vMGW

17

ISU17

• 1 association set for M3UA/IUA SCTP

• 2/4/8 M3UA/IUA SCTP associations for SIGUS (1 / SIGU)

• 2/4 M3UA/IUA SCTP associations for SISUs (2 / SISU) • SLS 4 bits: 2, 4, 8 or 16 associations

SIGU10

H.248

SIGU9

H.248

SIGU12

H.248

SIGU11

H.248

SIGU14

H.248

SIGU13

H.248

SIGU16

H.248

SIGU15

H.248

H.248/SCTP association

M3UA/SCTP association

H.248:

* H.248 association control

* H.248 Context handling

Call control, M3UA, IUA, PCM control, MAP/CAP, SIP, etc…

PLMN BSC

PSTN PBX RNC

SGW

H.248

SGW

H.248

SGW

H.248

SGW

H.248

SGW

H.248

SGW

H.248

NIWU/IWS1

SGW

H.248

SGW

H.248

SGW

H.248

SGW

H.248

SGW

H.248

TDM/ATM SS7 links are

processed by all ISUs

TDM/ATM Circuit Groups (CGRs) for

Userplane are configured to all ISUs

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MGW

H.248 LB in MGW 1/2

• 16 + 1 SIGUs

• 17 + 1 ISUs MSS/GCS

M3UA

H.248 SIGU0

H.248

vMGW

1-4

H.248

ISU1

ISU0 ISU2 ISU3 ISU4 ISU5 ISU13 ISU14 ISU15 ISU16 ISU17

MISU

vMGW

5-8

MISU

H.248

vMGW

9-12

MISU

H.248

vMGW

13-16

MISU

H.248

• SIGU’s H.248 associations re-configured to MISUs

• M3UA associations removed from MISU to SISUs

• TDM resources stays in vMGWs 1-16 • Max. 30 vMGW/MISU (ISU)

• Max. 30 CGR / vMGW

• Max. 128 PCM / vMGW

• 1 association set for M3UA/IUA SCTP

• 2/4/8 M3UA/IUA SCTP associations for SIGUS (1 / SIGU)

• 2/4 M3UA/IUA SCTP associations for SISUs (2 / SISU) • SLS 4 bits: 2, 4, 8 or 16 associations

H.248 Context handling

H.248 M3UA

IUA

SIGU2

H.248 H.248

SIGU1

H.248

SIGU4

H.248

SIGU3

H.248

SIGU6

H.248

SIGU5

H.248

SIGU8

H.248

SIGU7

H.248

SIGU10

H.248

SIGU9

H.248

SIGU12

H.248

SIGU11

H.248

SIGU14

H.248

SIGU13

H.248

SIGU16

H.248

SIGU15

H.248

Call control, M3UA, IUA, PCM control, MAP/CAP, SIP, etc…

PLMN BSC

PSTN PBX RNC

NIWU/IWS1

SGW

SISU

SGW

SISU

SGW

SISU

SGW

SISU

SGW

SISU

SGW

SISU

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SIGU capacities (M14.6 SW) * relevant to H.248, BSSAP and TDM trunks

Number of simultaneous half calls per SIGU

2.300 (MSS) *

1.920 (MSS IUA)

3.000 (GCS)

Max. number of MEGACO contexts per SIGU 4.500

Number of controlled user plane terminations (external

PCM connected to MGW) per SIGU 192 PCMs

SIGU (CP816)

Number of vMGWs per MSS 100

Number of vMGWs per SIGU without H.248 Load Balancer 10

Number of vMGWs per SIGU with H.248 Load Balancer 30

Number of H.248 Load Balancer pools per MSS 5

Routes per MSS 4 096 / 6 000 *

Circuit groups per MSS 3 072 / 6 000 *

Routes per BSS Pool (in case of Ater) 1

Circuit Groups per BSS Route (CGRs) 8

Circuits per circuit group 4 096

Max. controlled virtual PCMs 15 936

vMGW

1

SGW

H.248

ISU1

SIGU2

M3UA

IUA

H.248

SIGU2

M3UA

IUA

H.248

SIGU1

M3UA

IUA

H.248

H.248 M3UA

IUA

MGW

MSS/GCS

* requires M14.6 TOP SW

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ISU capacities (U4.2/U5.0 SW + CCP18C) Max number of ISUs 18 (17+1)

Connection attempts (“BHCA”) per ISU (U4.2)

Connection attempts (“BHCA”) per MGW U4.2)

Connection attempts (“BHCA”) per ISU (U5.0)

Connection attempts (“BHCA”) per MGW (U5.0)

215.000

3.000.000

285.000

4.000.000

Max. number of simultaneous connections per ISU (U4.2/U5.0)

Simultaneous connections with 45sec of MHT (U4.2)




13.000

2.688

5.375

3.563

7.125

# of vMGW / ISU

Max. # of vMGW / MGW

1…5

85

Max. # of CGR per ISU

Max. # of CGR per vMGW

Max. # of CRCT / CGR (128 PCM x 32 TSL/PCM)

50

10 (285 in U5.0 EP1)

4.096

Max # of ISUs 18 (17+1)

Min. / max. # of Master-ISUs /MGW

Min. / max. # of Slave-ISUs /MGW

Min. / max. # of Master-ISUs /MGW (H.248 LB by full mesh config.)

Min. / max. # of Slave-ISUs /MGW (H.248 LB by full mesh config.)

2 / 4

2…15

2...17

2...17

Connection attempts (“BHCA”) per 2 / 4 MISU (U4.2)

Connection attempts (“BHCA”) per 2 / 4 MISU (U5.0)

1.76M / 3M

2.32M / 4M

Max. # of simultaneous connections per SISU (U4.2/U5.0) 13.000

# of vMGW per MISU

Max # of vMGW per MGW

1…30

85

Max. # of CGR per MISU

Max. # of CRCT / MISU (30x 128 PCM x 32 TSL/PCM)

30

122.880

H.248 Load Balancer: Master-ISU (MISU) & Slave-ISU (SISU) in MGW

vMGW

1

SGW

H.248

ISU1

SIGU2

M3UA

IUA

H.248

SIGU2

M3UA

IUA

H.248

SIGU1

M3UA

IUA

H.248

H.248 M3UA

IUA

MGW

MSS/GCS

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Parameter 002:0727 MAX_NBR_OF_VMGW_IN_UNIT Descriptive name

Maximum number of Virtual Media Gateways in unit

Modifiable

YES

Description

This parameter defines the maximum number of Virtual Media Gateways per one ISU

unit.

Default value(s)

5D – means 5 VMGW per ISU

Allowed values

1D - 30D – Means max 30 VMGW per ISU

Forbidden values

-

Dependence

Dependence on other parameters does not exist.

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Virtual Media Gateway handling, JV MML Command group in MGW

This is section is only for MML commands, valid for MGW based on IPA2800..

• Use JVJ to add (S)ISU.

• Use JVK to modify (S)ISU H.248 load balancer state.

• Use JVL to remove (S)ISU.

• Use JVI to interrogate virtual MGW.

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Comparison of H248 Loadbalancer

DX / IPA Feature is optional

Must be activated by License

IPDU is used 1+1

EMB is required

L3 is required in MSS

M (ISU) in MGW

S (ISU) in MGW

ATCA Feature is mandatory

Must be activated by License

IPDU is used max 5+1

HCLB in MGW

SISU in MGW

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SIP Loadbalancer

H.248 Load Balancer FN1840 available for


• MSS ATCA in Ma16.1(SR5.0)

Load Balancer for SIP FN 1828 available for


• Open MSS in Ma16.1 (SR5.0)

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Challenge:

• Currently MSS/NVS is contacted per SIP signaling unit where each unit has own IP address towards the peer network element

• External load balancer e.g. SBC or DNS is used for MSS

Solution:

• Integrated Load Balancer for SIP improves IP interconnectivity and IP address management

by introducing the IP Director Unit (IPDU) which provides only two redundant IP addresses

visible outside the MSS network element

Load Balancer for SIP

• The load distribution can be done within MSS instead of external DNS server • Removes the requirement for peer elements to support load balancing towards MSS • Reduced IP address cost – less need for public IP addresses • Topology hiding improves the IP security • Multihoming capability in SCTP provides excellent resiliency for SIP/SIP-I protocol

Operator benefits

SR5.0 SR4.0

Confidential


Load Balancer for SIP

Functionality:

• New Linux based IP Director Unit HW unit (IPDU)

introduced:

• Support for TCP, UDP and SCTP transport

• High availability configuration with N+1

• Managed by MSS Operating and Maintenance

Unit (OMU)

• Each IPDU is assigned with a load balancing group

consisting of multiple signaling units. The IPDU

monitors the state of signaling units and balances

new SIP sessions to available units

• SCTP Multihoming provides diverse paths in IP

network for resilient SIP messaging

Support required (e2e viewpoint):

• Requires L3 connectivity in MSS

• Load Balancer for SIP available for MSS DX200 in

M14.6 (SR4.0) and for Open MSS in Ma16.1 (SR5.0)

GISU GISU GISU

MSS/NVS

GISU GISU GISU

IPDU

IPDU IPDU

IPDU

Primary SCTP path

Secondary SCTP path

MSS/NVS

SR5.0

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SIP load balancer

SIP load balancer can be used to limit the number of IP addresses exposed outside the MSS/NVS for SIP interface purposes. This solution works for both SIP and SIP-I interfaces and in MSS, MGCF, standalone NVS and NVS application server roles. SIP load balancer is planned to work with TCP and UDP and SCTP.

The benefits of this feature are, on one hand to improve the interoperability with SIP aware network elements that do not support DNS or that require complex configurations because the MSS exposes many IP addresses for the same SIP interface (CGR). On another hand, it is possible also to use fewer public IPv4 addresses for the IPDUs than is currently required, reducing the number of IP addresses.

The load balancer functionality uses specific IPDU (IP Director Unit) functional units (with N+1 redundancy). The same IPDU technology is also used for H.248 load balancing as defined in H.248 Load Balancing in the MGW and the MSS. Also, one additional aggregating L3-enabled ESB24-A pair is used allowing L3 connectivity to the core site.

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SIP load balancer

SIP load balancer entities located in IPDU units will continuously monitor the state of SIGU and SCPU signaling units that are responsible for SIP signaling. External network elements having SIP and SIP-I connectivity towards the MSS will use the IP addresses of the IPDUs for SIP signaling.

SIP (over TCP/UDP/SCTP) uses different VIPs than H.248. With the Virtual IP address routing, the operator can define which IPDU handles that traffic.

In the MSS, a new Linux-based IPDU computer unit is used. It is recommended that the same IPDUs are used for both H.248 and SIP load balancers. Thus, more resilience is gained with fewer IPDUs. Either of the LBs can be deployed separately. However, the greatest benefits are realized if the H.248 load balancer is used both in the MGW and the MSS.

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Requirements

Software

To enable this feature, the following PRFILE commands need to be enabled:

• MSC_SIP_TUNNELING_SUPPORT (002:1320)

• MSC_MGCF_SUPPORT (002:1321)

The SIP Load Balancing functionality is controlled by the FEA1462 license.

FEA1462 is an On/Off license.

Hardware open MSS DX MSS

The Open MSS release supports a simplified Layer 2 connectivity model, and does not require a loop topology for external connectivity or usage of the Spanning Tree Protocol. LAN connection principle in M16.1 level Open MSS with IPDUs displays a simplified site connectivity configuration supporting Load Balancing.

In DX MSS: To get 1Gbit/s links for SIP Load Balancer between the L2 and L3 switches, use the ESB24-D SWU variant as a L2 switch in the IPDU cabinet.

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SIP Load Balancer Overload Control functionality:

If the SIP Load Balancer feature is activated, the SIP Load Balancer Overload Control functionality can be configured with the SLIPLB_OLC_CONTROL PRFILE parameter.

This parameter controls if the ticketing service is used to protect the IPDUs used. The default value of this parameter is ‘TRUE’.

ZWOI:12,126;

Confidential


General IP

The SIP Load Balancer feature allows a number of IPDU units to be configured as dedicated SIP load balancing units for incoming SIP access, SIP trunk and MGCF/SIP-I traffic.

If both the UDP/TCP and the SCTP MH transports are available for SIP, three virtual IP addresses are visible externally. Multiple signaling units are accessed behind a single (external) IP address.

The actual number of externally visible IP addresses is directly proportional to the number of SIP load balancing service instances (SIP LBSes). Each SIP LBS needs a minimum of one IP address (for UDP/TCP and SCTP single-homing) or two IP addresses (used for SCTP multihoming).

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General IP

With SIP load balancing, the signaling load can be distributed within the MSS instead of using an external DNS server. SIP load balancing enables a service or application to be hosted on multiple servers in the signaling unit cluster, through having one, or as many as five, SIP load sharing groups (LSGPs).

With SIP load balancing, only the (virtual) IP addresses configured for each SIP LSGP are visible outside the MSS/NVS. Multiple computer units with several physical (internal) IP addresses can be hidden behind a single virtual (external) IP address. The IPDU forwards the SIP packets to GISU units based on their unit-specific physical IP addresses —that is, on their MAC addresses— using L2 routing. The SIP traffic from the GISU units belonging to one or more SIP LSGPs is forwarded to the IPDU using a local IP-based default gateway configuration for the virtual IP addresses (VIPs).

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IP connectivity for LB in open MSS

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DX Connection in DX MSS

SWU 40 and SWU 41

Are ESB24_D

SWU 6 and SWU 7

Should be ESB24_D or

As alternative ESB24_A

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MML

SIP Address Configuration Handling, JI Command Group

JIM Modify SIP addresses

Use this command to create and modify SIP listening points. When using this feature, any of the available non-multihomed SIP interfaces can be set as a Virtual IP (VIP) address when the transport protocol used is SCTP.

Load Balancer Configuration Handling, JJ Command Group

The command group is used for configuring the SIP load balancer. LIKE IN H248 LB

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new URI parameter (YOP)

When the feature is active, MSS/NVS inserts "YOP" parameter into SIP messages.

• YOP is globally unique, e.g. the MSS number and the used signaling unit impact YOP generation.

• The load balancer reads YOP and routes the SIP messages to the correct unit.

• YOP is part of the existing headers (Via, Record-Route, Contact). The used header depends on the call case.

A new URI parameter (YOP) is added to the own SIP URI every time the NVS needs to put its address to a header in an outgoing SIP request or response using a SIP interface (e.g. Contact, Route, Record-Route, etc.).

It is needed by the SIP LB in order to find the correct signaling unit to which all requests and responses of the same SIP dialogue should be routed.

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Comparison of SIP Loadbalancer

DX Feature is optional

Must be activated by Licence

IPDU is used 1+1

EMB is required

L3 is required in MSS

Virtual IP address used for external communication (could not be reused by H248)

ATCA Feature is mandatory

Must be activated by Licence

IPDU is used max 5+1

Confidential


M3UA Load Balancer

Load Balancer for M3UA FN 1949 available for


• Open MSS in M16.0EP1 (SR4.2) with IP Forwarding

• Open MSS in Ma16.1 (SR5.0) with IPDU

Confidential


Challenge • SS7 over IP is rapidly replacing traditional SS7 over TDM. This increases the demand for easy

deployment and management of the IP based signaling network

• For some network topologies it is desirable to reduce the number of signaling relations and exposed IP addresses between peering elements while in other topologies more distributed signaling relations are needed

• In complex networks with varying traffic patterns the task of ensuring even load balancing on the network element level can be challenging

Solution • The Load balancer for M3UA feature enables the MSS and MGW to be connected to the control plane

network through few, dedicated signaling units (for BSSAP, RANAP, MAP, CAP, INAP, SINAP, ISUP, BICC)

• The MSS and MGW will internally take care of load balancing to ensure an even utilization of available signaling units

Load balancer for M3UA

• The number of exposed IP addresses outside the MSS and MGW is reduced dramatically -> topology hiding

• Automatic internal load sharing will remove the need for continuous manual optimization of the control plane configuration

• Simplified control plane network • More efficient load sharing enables higher utilization of signaling resources and reduced risk of

overloading certain signaling units

Operator benefits

SR3.3

Confidential


Load balancer for M3UA

Functionality:

• Certain signaling units can be configured to terminate all M3UA signaling connections – all

external M3UA signaling originated from or terminated at the network element will be sent

or received through these assigned units

• The number of signaling units required for terminating the signaling connections

depends on traffic volume and resilience requirements

• In the MSS and MGW the signaling messages are distributed internally to all available

signaling units for processing in order to achieve even load sharing

MSS1 SU

SU

SU

SU

SU

MSS2 SU

SU

SU

SU

SU

MGW1 SU

SU

SU

MSS1 SU

SU

SU

SU

SU

MSS2 SU

SU

SU

SU

SU

MGW1 SU

SU

SU

Internal load balancing

SU = Signalling Unit

SR3.3

Confidential


SIGU-1 and SIGU-2 have been selected as M3UA LB units. ( DX MSS)

ZUSI:SIGU;

UNITS IN SPECIFIED WORKING STATE

UNIT PHYS STATE LOCATION INFO

SIGU-0 003A WO-EX AMTA

SIGU-1 003B WO-EX -

SIGU-2 003C WO-EX -

SIGU-3 003D WO-EX AMTA

SIGU-4 003E SP-EX IDLE AMTA

SIGU-5 003F SE-NH AMTA

SIGU-6 0040 SE-NH AMTA



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M3UA Loadbalancer for DX and Open MSS in M16.1

M3UA_LOAD_BALANCE On/Off license. Before the following feature activation steps, you need to select an appropriate number of SIGU units to behave as dedicated M3UA LB units to handle all M3UA-based signaling connections.

ZW7I:FEA,FULL:FEA=1510;

where 1510 is the feature code

IPDU_BASED_M3UA_LB On/Off license.

ZW7I:FEA,FULL:FEA=3479;

where 3479 is the feature code

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Summary for M3UA Loadbalancer in Open MSS

Evolution steps from M16.0 via M16.0EP1 to Ma16.1

From GISU based via IP forwarding to IPDU based LB

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Overview of the Open MSS Control Plane connectivity evolution

M16.0 First Delivery elements

• Physical connectivity:

• All control plane traffic is connected via the Hub blades using a L3 model

• Load Balancing:

• Only GISU based M3UA Load Balancer is supported (and it is mandatory*)

M16.0EP1 FD elements


• All control plane traffic is

connected via the IPDU

blades using a L2 model • Load Balancing:

• GISU based M3UA

Load Balancer is still

mandatory*

• IPDUs are in IP

forwarding mode (no LB

performed)

Ma16.1 FD elements


• All control plane traffic is

connected via the IPDU

blades using a L2 model • Load Balancing:

• H.248, SIP and M3UA

traffic is load balanced

using the IPDUs

RTMRTM

RTMRTM

RTM

RTM storage

O&M

OMU

H

u

b

FI BI, between

shelves

RTM

RTM storage

CHU

VMU

IPDU

CMM

Billing

GISU

VLRU

STU

CMU

OLCM

Control plane

RTMRTM

RTMRTM

RTM

RTM storage

O&M

OMU

H

u

b

FI BI, between

shelves

RTM

RTM storage

CHU

VMU

IPDU

CMM

Billing

GISU

VLRU

STU

CMU

OLCM

Control plane

RTMRTM

RTMRTM

RTM

RTM storage

O&M

OMU

H

u

b

FI BI, between

shelves

RTM

RTM storage

CHU

VMU

IPDU

CMM

Billing

GISU

VLRU

STU

CMU

OLCM

Control plane

See notes for further explanations

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IPDU Configuration Rules

• 1st shelf must have two IPDUs with RTMs, equipped to slots 7 and 10

• Open MSS 1st shelf has two IPDUs and following shelves have one additional IPDU by default(slot 7).

Nokia Siemens Networks

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Shelf IPDU units

1st shelf IPDU-0 (WO)

IPDU-1 (WO)

2nd shelf IPDU-2 (SP)

3rd shelf IPDU-3 (WO)

4th shelf IPDU-4 (WO)

5th shelf N/A

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Site Connectivity before IP Forwarder Migration

MSS

GISU-0

IPDU-1

GISU-1

GISU-2

GISU-3

GISU-n

GISU-4

Peer network

element

IPDU-2

IPDU-0

SP-EX WO-EX SCTP association 1

SCTP association 2

TCP/UDP

10.22.95.249 (3/1 of AHUB) CE-1

CE-2

AHUB

AHUB

SCTP PRI: 10.23.151.2

SCTP SEC: 10.23.152.2

TCPUDP: 10.23.153.66

10.22.95.253 (3/4)

GW: 10.23.152.1

GW: 10.23.151.1 GW: 10.23.153.65 (VRRP)

10.22.96.249 (3/1)

10.22.96.253 (3/4)

10.22.95.250(3/1)

10.22.96.250 (3/4)

10.22.95.253(3/1)

10.22.96.253 (3/4)

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Site Connectivity after IP Forwarder Migration

MSS

GISU-0

IPDU-1

GISU-1

GISU-2

GISU-3

GISU-n

GISU-4

Peer network

element

IPDU-2

IPDU-0

IP forwarder

unit

SP-EX WO-EX

IP forwarder

unit

SCTP association 1

SCTP association 2

TCP/UDP

GW: 10.23.152.1

GW: 10.23.153.65 (ex-VRRP)

VLAN1200:10.22.96.2

VLAN1100: 10.22.95.2

SCTP PRI: 10.23.151.2

SCTP SEC: 10.23.152.2

TCPUDP: 10.23.153.66

CE-1

CE-2

GW: 10.23.151.1

10.22.95.1

10.22.96.1

10.22.97.2 VLAN1300 IF

10.22.97.3 VLAN1300 IF

10.22.97.1 HSRP (CE-1 active)

VLAN1300 & 1310: 10.22.97.4

VLAN1300 & 1310: 10.22.97.5

Confidential


IPDU Connectivity Details for M16.0 EP1

• Static routing is used GISUs,

IPDUs and site routers.

• Resiliency is based on

• MSTP inside the element

• SCTP multihoming

• Bonding interface with GARP

based Ethernet port

switchover

• Garrier grade IP address with

GARP based Ethernet port

switchover

MSTP between the

AHUB3-As for

connectivity

between shelves

SCTP Multihoming and

Bonding interface

IP BackBone

SCTP 2nd path

IPDU-1

ACPI4-A

IPDU-2

ACPI4-A

GISU-1

ACPI4-A

GISU-N

ACPI4-A

SCTP

primary path

Bonding interface

Carrier Grade

IP address

Site L2/L3

switch/router

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Site Connectivity before IP Forwarder Migration

Confidential


Site Connectivity After IP Forwarder Migration

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IP Forwarding ZQRH to interrogate or ZQRT to configure

UNIT : The computer unit whose TCP/IP stack parameters are configured

IPF: IP forwarding flag

TTL : IPv4 time-to-live value

SNL : Subnets are local flag

IAA: InATMARP flag

HOST NAME: The name of the host computer

HLIM: The hoplimit for IPv6 packets

CONFIGURED TCP/IP PARAMETER DATA

UNIT IPF TTL SNL IAA HLIM HOST NAME

------------------ --- --- --- --- ---- --------------------------------------

OMU-0 NO 64 YES YES 64 MYHOST

COMMAND EXECUTED

Confidential


Challenge:

• The number of Sigtran connections that one network element needs to support is increasing due to new signaling network planning preferences such as full mesh signaling networks and I-HSPA with direct Sigtran connections to each I-BTS

Solution: • IP Director Unit (IPDU) is fully resilient M3UA Load Balancer Unit which performs

network element internal signaling load balancing in Sigtran MTP3 User Adaptation Layer

IPDU based Load Balancer for M3UA

• In the Open MSS architecture all the IP based signaling traffic is transferred via Load Balancer Unit that performs even load balancing to all the Signalling Units of the network element

• Easy and simple address management and signaling network configuration • Topology hiding improves the IP security

Operator benefits

SR5.0

Confidential


IPDU based Load Balancer for M3UA

Functionality:

• Pool of Generic Signalling Units (GISU)

share the same Signalling Point Code

(SPC). IPDUs perform automatic load

balancing of M3UA message traffic

towards the GISUs

• Separate GISUs are not visible to the

external Sigtran network

• In the signaling network the M3UA

messages are transported using SCTP

associations.

• SCTP Multihoming available for IP

network resiliency

• Only two redundant IP addresses

visible to external networks

• IPDU supports N+1 resiliency

SR5.0

GISU

MSS/NVS

IPDU

SCTP association #1

GISU GISU GISU

IPDU

SCTP association #2

BSSAP

RANAP

MAP

CAP

INAP

ISUP

BICC

Sigtran

network

Support required (e2e viewpoint): • IPDU HW Unit is part of standard Open MSS HW configuration

• Note: for DX200 MSS the M3UA Load Balancing is based on Signalling

Unit based message balancing solution (no IPDU needed)

Confidential


In Open MSS M16.1

The configuration of M3UA load balancing in the Open MSS consists of two main parts:

1. the configuration of SCTP associations which carry M3UA traffic from the external M3UA network to the IPDU units

2. the configuration of IPDU units as M3UA load balancers to forward load balanced M3UA traffic over the internal BI interface to GISU units

The IPDU-based M3UA LB does not support IUA protocol.

Confidential


IPDU-1 Interfaces + static route to site router

IPDU-1

BOND0 UP 1500

-> EL0 EL1

EL0 UP 1500

EL1 UP 1500

EL4 UP 1500 L 10.22.75.106/29

L 10.22.75.107/29

L 10.22.75.108/29

EL5 UP 1500 L 10.22.76.106/29

L 10.22.76.107/29

L 10.22.76.108/29

VLAN400 UP 1500 P 192.168.2.1/24

->BOND0 400 0/0 P 192.168.2.2/24

P 192.168.2.3/24

L 192.168.2.100/24

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OYI:NAME=M3UAC;

INTERROGATING ASSOCIATION SET DATA ASSOCIATION SET NAME ASSOC SET ID SCTP USER ROLE

-------------------- ------------ --------- --------

M3UAC 0 SS7 CLIENT

ASSOC. ASSOC ID PARAMETER SET

IND UNIT IN UNIT NAME STATE

--- ------- --------- ---------------- --------------------

0 IPDU-0 2 SS7 DOWN-BY-USER

SOURCE ADDRESS 1 . . . . . : 10.22.71.82

SOURCE ADDRESS 2 . . . . . : 10.22.72.82

SOURCE PORT . . . . . . . : 1500

PRIMARY DEST. ADDRESS . . : 10.22.65.106/29

SECONDARY DEST. ADDRESS . : 10.22.66.106/29

DESTINATION PORT . . . . . : 2500

DATA STREAM COUNT . . . . : 16

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Load Balancer definitions

ZJJI:TYPE=UNIT:UTYPE=IPDU,;

INTERROGATING LBS UNIT CONFIGURATION

IPD UNIT INFO

INT EXT

UNIT INDEX INTERFACE INTERFACE LBS NAME

---- ----- --------- --------- --------

IPDU 0 VLAN400 EL4 M3UALB0

IPDU 1 VLAN400 EL4

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Comparison of M3UA Loadbalancer

DX Signalling unit based, using

AMTA parameter

ATCA GISU based or from Ma16.1

on IPDU based

05_ load balancer

Documents

mgw load balancer

load balancer unit

mss l3

mss atca

open mss

mss cabinets

single physical mgw

mss dx200 available