Cisco Cisco ASR 5000
Attach Rate Throttling
▀ How it Works
▄ SGSN Administration Guide, StarOS Release 18
processed at the configured attach rate and then forwarded to the identified Session Manager queue for normal
processing. This allows the operator to cap the rate at which new requests are accepted by the SGSN. An overload
scenario can be prevented with the introduction of the Attach Rate Throttling feature. The intermediary queues are
operational only when the Attach Rate Throttling feature is enabled. If the feature is disabled, attach requests are
directly queued for processing at the identified Session Manager.
processing. This allows the operator to cap the rate at which new requests are accepted by the SGSN. An overload
scenario can be prevented with the introduction of the Attach Rate Throttling feature. The intermediary queues are
operational only when the Attach Rate Throttling feature is enabled. If the feature is disabled, attach requests are
directly queued for processing at the identified Session Manager.
Limitations
The operator must ensure that an optimal attach rate must be configured based on the network conditions:
1. If the incoming requests arrive at a very high rate and the attach rate configured to a very low rate, the requests will be
dropped from the intermediary queue once the queue is full. The IMSI Manager can send a reject response with the
appropriate reject cause codes for such all dropped requests or silently drop the requests.
appropriate reject cause codes for such all dropped requests or silently drop the requests.
2. If the configured attach rate is very low, the requests waiting time in the queue increases. The "t3310" timer at the MS
expires and the MS will have to re-transmit the request. The IMSI Manager drops all requests which have waited in the
queue for more than the configured wait time.
queue for more than the configured wait time.
The configured Attach rate must have an optimal processing rate and waiting time.