User Manual

Chapter 4 - Operation and Administration Using the CLI NPU Configuration
4Motion 392 System Manual
In certain cases, such as entity reset, other entities are not aware of service
termination of an MS in that entity, and keep maintaining the MS context. This
may result in service failure, excessive consumption of memory resources and
accounting mistakes.
The keep-alive mechanism should be used to clear MS context from all network
entities when it is de-attached from the BS, and de-register MS from the network
when its context becomes unavailable in one of its serving function locations.
When the keep-alive mechanism is enabled the ASN-GW periodically polls other
ASN entities-of-interest (BSs and other ASN-GW) and waits for their responses. In
case of no keep-alive response, the ASN-GW shall make further actions, such as
clearing the applicable MS(s) context.
The ASN-GW builds a list of BS-of-interest and ASN-GW-of-interest which it must
poll. ASN-GW shall poll other ASN-GW in case data-path was established over R4
during inter-ASN HO (hierarchical data-path establishment).
The list shall be dynamically updated; the ASN-GW tracks all BSID(s) in all MS(s)
contexts it holds, and dynamically updates the list of BSs-of-interest. When a new
MS is attached to a BS that does not exist in the list, it will be added it to the list.
When the last MS(s) with specific BSID makes network exit, the ASN-GW shall
remove the BS from the list.
The same dynamic behavior applies also to ASN-GW-of-interest list. When
hierarchical data-path is established, the Data Path Function ASN-GW updates
its ASN-GW-of-Interest list with Relay Data Path ASN-GW and vice-versa. The
trigger is R4 data-path creation.
The ASN-GW periodically polls the BS(s) and ASN-GW(s) for keep-alive. The
polling mechanism is independent and unrelated for every BS-of-interest or
ASN-GW-of-interest the ASN-GW polls.
The keep-alive mechanism uses configurable retry timer and retries counter.
Upon expiration of the retry timer, the ASN-GW resends the ASN Keep-Alive
request message. Upon expiration of the retries counter, the ASN-GW assumes
failure of the polled BS/ASN-GW and clears the contexts of all MS(s) served by
that BS/ASN-GW.
In addition, the ASN-GW verifies that for each polled entity that the
"Last-Reset-Time" UTC value of poll N+1 is equal to the value of poll N. If the
"Last-Reset-Time" UTC value of poll N+1 is higher than the value of poll N, this
mean that the BS/ASN-GW went through reset state during the interval between
two consecutive polls. In this case, the ASN-GW shall clear all MS(s) contexts,
served by that specific BS/ASN-GW that are "older" than BS/ASN-GW life after