[Home](./index.md) > [sip.js](./sip.js.md) > [ClientTransaction](./sip.js.clienttransaction.md) > [onRequestTimeout](./sip.js.clienttransaction.onrequesttimeout.md) ## ClientTransaction.onRequestTimeout() method A 408 to non-INVITE will always arrive too late to be useful (\[3\]), The client already has full knowledge of the timeout. The only information this message would convey is whether or not the server believed the transaction timed out. However, with the current design of the NIT, a client cannot do anything with this knowledge. Thus, the 408 is simply wasting network resources and contributes to the response bombardment illustrated in \[3\]. https://tools.ietf.org/html/rfc4320\#section-4.1 Signature: ```typescript protected onRequestTimeout(): void; ``` Returns: `void`