Engineering Rules

This section provides SGSN-specific 2.5G, 3G , and common engineering rules or limit guidelines for the current release. These limits are hardcoded into the SGSN system and are not configurable. The limits are documented here because they should be considered prior to configuring an SGSN for network deployment.

Generic platform and system rules or limits can be found in the “Engineering Rules” appendix in the System Administration Guide.

Service Rules

The following engineering rules define the limits for the various services configured on the SGSN (system):


Table 1. Service Rules for the SGSN
Features Limits Comments

Maximum number of (all) services (regardless of type) configurable per SGSN (system).

256

This limit includes the number of GPRS services, SGSN services, SGTP services, IuPS Services, and MAP Services.

Max. number of eGTP services supported by a GPRS/SGSN service.

1

When configured for S4-SGSN.

The same eGTP service should be associated with both the GPRS and the SGSN service.

Max. number of HSS peer services supported by a single GPRS or SGSN service.

1

When configured for S4-SGSN.

Max. number of Gs services supported by a single GPRS or SGSN service.

1

Although the limit is 1 Gs Service configured per GPRS Service or SGSN Service, the GPRS or SGSN service can access multiple Gs Services using Operator Policies.

Max. number of MAP services supported by a single GPRS (2G) or SGSN (3G) service.

1

Although the limit is 1 MAP Service configured per GPRS Service or SGSN Service, the GPRS or SGSN service can access multiple MAP Services using Operator Policies.

Max. number of Gs services supported on an SGSN (system)

12

Maximum number of LACs per Gs service

128

Max. number of MAP Service configurations supported by a single SCCP network.

1

Max. number of SGTP services supported by a single GPRS or SGSN service.

1

 Although the limit is 1 SGTP Service configured per GPRS Service or SGSN Service, the GPRS or SGSN service can access multiple SGTP Services using Operator Policies.


Note:

Maintaining a large number of services increases the complexity of management and may impact overall system performance. Therefore, it is recommended that a large number of services only be configured if your application absolutely requires it. Please contact your service representative for optimization suggetions and more information on service limits.

SGSN Connection Rules

The following limitations apply to both 2G and 3G SGSNs.
Features Limits Comments

Maximum number of entry authentication triplets (RAND, SRES, and KC) and quintuplets stored per MM context

 5

5 (unused) + 5 (used) Triplets/Quituplets

Maximum number of logically connected SMSCs

 no limit

Limit would be based on the number of routes if directly connected. No limit if GT is used.

Maximum number of logically connected HLRs

 no limit

Limit would be based on the number of routes if directly connected. No limit if GT is used.

Maximum number of logically connected EIRs

 1

SGSN will be connected to only 1 EIR.

Maximum number of logically connected MSCs

 see comment

System supports a max of 128 LACs per Gs service and a max of 12 Gs service.

Maximum number of concurrent PDP contexts per active user

 11

Maximum number of logically connected GGSNs per Gn/Gp interface

 20000

Maximum number of packets buffered while other engagement

Maximum number of packets buffered in suspended state

Maximum number of packets buffered during RAU

 see comment

- Minimum of 2KB/subscriber.

- Maximum of 10KB/subscriber -- if buffers are available in the shared pool*. (*SGSN provides a common buffer pool for 2G and 3G subscribers of 10M per session manager; buffers to be shared by all subscribers “belonging” to that session manager.)

- Additional 2G subscriber buffer pool in BSSGP.


Operator Policy Rules

The following engineering rules apply for the entire system when the system is configured as an SGSN.

The limits listed in the table below are applicable for an ASR 5000 running a standalone SGSN application on a PSC2/PSC3. Limits may be lower when using a PSC1 or in combo nodes, such as SGSN+GGSN.

Features Limits Comments

Maximum number of Operator Policies

 1000

Includes the 1 default policy.

Maximum number of Call-Control Profiles

 1000 .

Maximum number of APN Profiles

 1000 .

Maximum number of IMEI Profiles

 1000 .

Maximum number of APN Remap Tables

 1000 .

Maximum number of APN remap entries per APN Remap Table

 100 .

Maximum number of IMSI ranges under SGSN mode

 1000 .

Maximum number of IMEI ranges per operator policy

 128 .

Maximum number of APN profile associations per operator policy

 128 .

Maximum number of call-control profiles per opreator policy

 1 .

Maximum number of APN remap tables per operator policy

 1 .
Call-Control Profiles . .

Maximum number of equivalent PLMN for 2G and 3G

15 Mandatory to configure the IMSI range. Limit per call-control profile.

Maximum number of equivalent PLMN for 2G

15 Limit per call-control profile.

Maximum number of equivalent PLMN for 3G

 15 Limit per call-control profile.

Maximum number of static SGSN addresses

 256 Limit per PLMN.

Maximum number of location area code lists

 5 .

Maximum number of LACs per location area code list

 100 .

Maximum number of allowed zone code lists

 10 .

Maximum number of allowed zone code lists

 no limit For Release 12.2

Maximum number of LACs per allowed zone code list

100 .

Maximum number of integrity algorithms for 3G

2 .

Maximum number of encryption algorithms for 3G

3 .
APN Profiles . .

Maximum number of APN profiles

 1000 .

Maximum number of gateway addresses per APN profile

 16 .


SS7 Rules

SS7 Routing


Table 2. SS7 Routing Rules for SGSN
Features Limits Comments

Maximum number of SS7 routing domains supported by an SGSN

 12

Maximum number of SS7 routes supported by an SGSN

 2048

This includes the self point code of the peer, 1 per link-set and 1 per peer-server

Maximum number of routes possible via a link-set

 2048

This includes the self point code of the peer, 1 per link-set and 1 per peer-server

Maximum number of routes possible via peer-server

 2048

This includes the self point code of the peer, 1 per link-set and 1 per peer-server

Maximum number of different levels of priority for link sets used in a single route set

 16



SIGTRAN


Table 3. SIGTRAN Rules for SGSN
Features Limits Comments

Maximum number of peer servers

 144

Maximum number of peer servers per SS7RD

 144

Maximum number of PSPs per peer server

 4

Maximum number of ASPs per SS7RD

 4

Maximum number of SCTP endpoints per ASP

 2

Maximum number of of SCTP endpoints per PSP

 2

Maximum number of SCTP endpoints per PSP (dynamically learnt)

 5



Broadband SS7


Table 4. Broadband SS7 Rules for SGSN
Features Limits Comments

Maximum number of MTP3 linksets

 256

Maximum number of MTP3 linksets per SS7RD

 144

Maximum number of MTP3 links per linkset

 16

Maximum number of MTP3 links per combined linkset

 16



SCCP


Table 5. SCCP Rules for SGSN
Features Limits Comments

Maximum number of SCCP networks

 12

Maximum number of destination point codes (DPCs)

 2048

Maximum number of SSNs per DPC

 3



GTT


Table 6. GTT Rules for SGSN
Features Limits Comments

Maximum number of associated GTTs

 16

Maximum number of actions per association

 8 .

Maximum number of actions per association

 15 For Release 12.2

Maximum number of address maps

 4096

Maximum number of out-addresses per address map

 5



SGSN Interface Rules

The following information relates to the virtual interfaces supported by the SGSN:

System-Level


Table 7. System Rules on the SGSN
Features Limits Comments

Maximum supported size for IP packets (data)

 1480

Maximum recovery/reload time

 17 mins.



3G Interface Limits


Table 8. 3G Interface Rules for SGSN
Features Limits Comments

Maximum number of RNCs

 See comment

Supports upto 144 directly connected RNC and 1024 indirectly connected through gateways.

Maximum number of RNCs controlling the same RA

 no limit

Maximum number of RAIs per RNC

 2500 .

Maximum number of RAIs per SGSN

 2.5K

2.5k is the recommended max RAI per SGSN, however, there is no hard limit imposed. Adding more RAIs may lead to memory issues

Maximum number of GTPU addresses per SGTP service

 12



2G Interface Limits


Table 9. 2G Interface Rules - Gb over Frame Relay
Features Limits Comments

Maximum number of NSEs

 2048

Limit is total of FR + IP

Maximum number of RAIs per SGSN

 2.5K

2.5k is the recommended max RAI per SGSN, however, there is no hard limit imposed. Adding more RAIs may lead to memory issues

Maximum number of NSEs controlling the same RA

 no limit

Maximum number of NSVCs per NSE

 128

Maximum number of BVCs per NSE

 max / SGSN is 64000

Maximum number of cell sites supported

 64,000




Table 10. 2G Interface Rules - Gb over IP
Features Limits Comments

Maximum number of NSEs

 2048

Limit is total of FR + IP

Maximum number of Local NSVLs per SGSN

 4

Maximum number of Peer NSVLs per NSE

 128

Maximum number of NSE controlling the same RA

 no limit

Maximum number of NSVCs per NSE

 512

Maximum number of BVCs per NSE

 max / SGSN is 64000

Maximum number of cell sites supported

 64000

Maximum number of 802.1q VLANs per Gb interface

 1024

Maximum number of RAIs per SGSN

 2.5K

2.5k is the recommended max RAI per SGSN, however, there is no hard limit imposed. Adding more RAIs may lead to memory issues