7.7.102 GGSN Back-Off Time

29.0603GPPGeneral Packet Radio Service (GPRS)GPRS Tunnelling Protocol (GTP) across the Gn and Gp interfaceRelease 17TS

The GGSN Back-Off Time information element indicates the time during which the SGSN should refrain from sending subsequent PDP Context requests to the GGSN for the congested APN for services other than emergency services.

The GGSN Back-Off Time information element is coded as shown in figure 7.7.102-1 and table 7.7.102.1

Bits

Octets

8

7

6

5

4

3

2

1

1

Type = 202 (decimal)

2 to 3

Length = n

4

Timer unit

Timer value

5 to (n+3)

These octet(s) is/are present only if explicitly specified

Figure 7.7.102-1: GGSN Back-Off Time

Table 7.7.102.1: GGSN Back-Off Time information element

Timer value

Bits 5 to 1 represent the binary coded timer value.

Timer unit

Bits 6 to 8 defines the timer value unit for the GGSN Back-off time as follows:

Bits

8 7 6

0 0 0 value is incremented in multiples of 2 seconds

0 0 1 value is incremented in multiples of 1 minute

0 1 0 value is incremented in multiples of 10 minutes

0 1 1 value is incremented in multiples of 1 hour

1 0 0 value is incremented in multiples of 10 hours

1 1 1 value indicates that the timer is infinite

Other values shall be interpreted as multiples of 1 minute in this version of the protocol.

Timer unit and Timer value both set to all "zeros" shall be interpreted as an indication that the timer is stopped.