11 List of system variables

08.163GPPBase Station System (BSS) - Serving GPRS Support Node (SGSN) interfaceGeneral Packet Radio Service (GPRS)Network serviceRelease 1999TS

Table 15/ 3GPP TS 08.16: System timers

timer name

timer value


relation to other timers


1s to 120s

Guards the blocking and unblocking procedures



1s to 120s

Guards the reset procedure



1s to 60s

Periodicity of the NS-VC test procedure




Guards the NS-VC test procedure


Table 16/ 3GPP TS 08.16: System counters

counter name





recommended value



recommended value



recommended value

Annex A (informative):
Recommended usage of BVCI and NSEI

This annex recommends a way to use BVCIs and NSEIs, avoiding huge and unflexible configuration data at the SGSN. This annex uses concepts defined in 3GPP TS 08.18 [5].

The key points are:

– A BVCI needs not to be unique within an SGSN, a BVCI is unique within an NS Entity. BVCI together with NSEI uniquely identify a BVC within an SGSN (the global identifier within an SGSN is BVCI+NSEI).

– BVCIs corresponding to PTP functional entities need not to be statically configured at the SGSN side: no fixed, permanent relationship is required in the SGSN between PTP BVCIs and NS-VCs.

With the NSEI, the SGSN needs not to be updated when a new cell (BVCI) is added to a BSS (NSEI). The pre-configuration of a cell in the SGSN and the constraint in the number of BVCs in an SGSN are not needed:

– The SGSN keeps detailed MM information about an MS while the MS is in the READY state, i.e. the SGSN knows the BVCI and NSEI which can be used to contact the MS for downlink transmission. The BVCI and NSEI are passed from NS to BSSGP and from BSSGP to the upper layers as a primitive parameter in every uplink packet received by the SGSN. Subsequent downlink LLC frames to this MS shall be transmitted by the SGSN over the BVC identified by this BVCI+NSEI.

– An SGSN in STANDBY state will page an MS before sending downlink traffic. The MS will respond with an LLC packet that will put the MM context in READY state and will deliver the BVCI and NSEI to the user of BSSGP.

For paging purposes, the SGSN only needs to know the correspondence between each Routeing Area and one or more NSEI(s) where to send the corresponding paging messages. Paging messages for a mobile in STANDBY state shall always be sent over BVCI=0 of an NSEI and for a mobile in READY state the circuit page is sent over the PTP BVC identified by the BVCI+NSEI. There may be NSEI(s) where BVCI=0 is not used.

Annex B (informative):
Change History

Date / Meeting




New ver

Creation of R99 version


May 2002

Updated to 3GPP TS style format. Reference clause cleaned up