Engineering Rules

Engineering Rules

This section provides SGSN-specific (2G, 3G, S4-SGSN related) 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):


Note

Maintaining a large number of services increases the complexity of management and may impact overall system performance. Therefore, we recommend that you limit the number of services that you configure and that you talk to your Cisco Service Representative for optimization suggestions and additional information on service limits.


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, 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.

SGSN Connection Rules

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

Table 2. Connection Rules for the SGSN
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 a standalone SGSN application . Limits may be lower when using a PSC1 or in combo nodes, such as SGSN+GGSN.

Table 3. Operator Policy Limits Applicable to the SGSN
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

300

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 Operator Policy

1

Maximum number of APN remap tables per Operator Policy

1

Maximum number of EIR Profiles

16

Maximum number of congestion-action-profiles

16
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 4. 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-server.

Maximum number of routes possible via a link-set

2048

Maximum number of routes possible via peer-server

2048

This includes one route for the peer-server and 2047 indirect routes.

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

16

SIGTRAN

Table 5. SIGTRAN Rules for SGSN
Features Limits Comments

Maximum number of peer servers per LinkMgr

512

Maximum number of peer servers per SS7RD

256

Maximum number of PSPs per peer server

12

Maximum number of ASPs per SS7RD

12

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 6. Broadband SS7 Rules for SGSN
Features Limits Comments

Maximum number of MTP3 linksets

512

Maximum number of MTP3 linksets per SS7RD

256

Maximum number of MTP3 links per linkset

16

Maximum number of MTP3 links per combined linkset

256

SCCP

Table 7. 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 8. GTT Rules for SGSN
Features Limits Comments

Maximum number of associated GTTs

16

Maximum number of actions per association

15

Maximum number of address maps

4096

Maximum number of out-addresses per address map

20

SGSN Interface Rules

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

System-Level

Table 9. 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 10. 3G Interface Rules for SGSN
Features Limits Comments

Maximum number of RNCs

See comment

Supports upto 256 directly connected RNC and 1024 indirectly connected through gateways.

Maximum number of RNCs controlling the same RA

no limit

Maximum number of RAIs per SGSN

16K 16K 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 RAIs per RNC

2.5K

Maximum number of GTPU addresses per SGTP service

12

2G Interface Limits

Table 11. 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

16K 16K 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 RAIs per NSE 2.5K

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

Whether or not Gb Flex is enabled.

Maximum number of cell sites supported

64,000
Table 12. 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 RAIs per SGSN

16K 16K 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 RAI per NSE

2.5K

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