Diameter Pending Answer Timers

A Pending Answer Timer sets the amount of time Diameter waits for an Answer after sending a Request to a Peer Node.

You can perform these tasks on an Active System OAM (SOAM).

In many cases, the Pending Answer Timer used by diameter is based on Diameter client response time requirements. Different Diameter clients for a single Application-ID and (Extended) Command Code can have differing response time requirements. The diameter Pending Answer Timer can be controlled based on Ingress Peer Node.

Users can assign a Pending Answer Timer (PAT) to Diameter messages based on Application ID and (Extended) Command Codes by configuring Transaction Configuration Rule (TCR) with Application ID plus (E)CC as a key in Transaction Configuration Sets.

A Pending Answer Timer can be associated with:

The Peer Node from which the request was received through Routing Option Set.
The Peer Node that the Request is sent to
The Transaction Configuration Set

Select the Pending Answer Timer using the following precedence selection criterion, highest to lowest priority:

If Transaction Configuration Set is selected on ingress Peer Node from which the Diameter Request was received, use Transaction Configuration Set and apply longest/strongest match search criteria for Diameter Request message parameters comparison and if a match is found, apply PAT assigned to Transaction Configuration Rule defined under this Transaction Configuration Set, if it exists.
The Pending Answer Timer assigned to the Routing Option Set for the Ingress Peer, if it exists.
The Pending Answer Timer assigned to the egress Peer Node to which the Request message is forwarded, if it exists.
Search Default TCS and apply longest/strongest match. Use PAT associated with best match, if any is found.
Default Pending Answer Timer.

The Diameter Routing Option Set provides an optional Pending Answer Timer element. If a configured Pending Answer Timer is specified in a Routing Option Set:

Routing Option Set Maximum per Message Forwarding Allowed must be > 1.
Routing Option Set Transaction Lifetime must be greater than or equal to the value of the Pending Answer Timer specified for the Routing Option Set.

The Routing Option Set Transaction Lifetime value controls the total time Diameter attempts to process a transaction, including re-routing attempts. Although the Routing Option Set can be associated with an Ingress Peer Node, Diameter evaluates the Routing Option Set Transaction Lifetime for expiration only at re-routing attempts, which means:

Routing Option Set Maximum per Message Forwarding Allowed must be > 1
Routing Option Set Transaction Lifetime must be greater than or equal to the value of the Pending Answer Timer specified for the Routing Option Set

Transaction Lifetime is not applicable or configurable if the Routing Option Set has re-routing disabled (Maximum per Message Forwarding Allowed value is set to 1)
Transaction Lifetime may be extended by as much as 1 Pending Answer Timer interval in some cases.

A Routing Option Set referenced by a Transaction Configuration Set Rule in Transaction Configuration Set cannot have a Pending Answer Timer configured, because each Transaction Configuration Rule always has an associated Pending Answer Timer.

Diameter selection of the Pending Answer Timer and Transaction Lifetime values to use when routing Requests upstream operates as indicated in Table 3-30.

Table 3-30 Diameter Pending Answer Timer and Transaction Lifetime Selection

Transaction Configuration Set entry exists for Appl-ID and (Extended) Command Code in Request being processed and is associated with Ingress Peer Node	Pending Answer Timer specified in Ingress Peer Node Routing Option Set?	Egress Pending Answer Timer specified in Egress Peer Node?	Default Transaction Configuration Set entry exists for Appl-ID and (Extended) Command Code in Request being processed?	Resultant Pending Answer Timer value used
Yes	Yes	Yes	Yes	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	No	Yes	No	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	Yes	No	No	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	Yes	Yes	No	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	Yes	No	Yes	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	No	Yes	No	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	No	No	Yes	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
Yes	No	Yes	Yes	Pending Answer Timer from Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria.
No	Yes	Yes	No	Pending Answer Timer in Ingress Peer Node Routing Option Set.
No	Yes	No	Yes	Pending Answer Timer in Ingress Peer Node Routing Option Set.
No	Yes	No	No	Pending Answer Timer in Ingress Peer Node Routing Option Set.
No	Yes	Yes	Yes	Pending Answer Timer in Ingress Peer Node Routing Option Set.
No	No	Yes	Yes	Egress Pending Answer Timer in Egress Peer Node.
No	No	Yes	No	Egress Pending Answer Timer in Egress Peer Node.
No	No	No	Yes	Pending Answer Timer from Default Transaction Configuration Set for Request's Appl-ID and (E)CC after applying longest/strongest search criteria if match occur otherwise System Default Pending Answer Timer.
No	No	No	No	System Default Pending Answer Timer.

The Diameter > Configuration > Pending Answer Timers

On the Diameter > Configuration > Pending Answer Timers page, you can perform the following actions:

Filter the list of Pending Answer Timers to display only the desired Pending Answer Timers.
Sort the list by a column in ascending or descending order by clicking the column heading. The default order is by Pending Answer Timer Name in ascending ASCII order.
Click Insert.

On the Diameter > Configuration > Pending Answer Timers [Insert] page, you can add a new Pending Answer Timer.

The Diameter > Configuration > Pending Answer Timers [Insert] page does not open if the maximum number of Pending Answer Timers (16) already exists in the system.
Select a Pending Answer Timer in the list and click Edit.

On the Diameter > Configuration > Pending Answer Timers [Edit] page, you can edit the selected Pending Answer Timer.

If the selected Pending Answer Timer has been deleted by another user, the Diameter > Configuration > Pending Answer Timers [Edit] page does not open.
Select a Pending Answer Timer in the list and click Delete. You can delete the selected Pending Answer Timer. You cannot delete the Default Pending Answer Timer.