---
title: Session Persistence with UDP protocols
slug: ps/help/en_us/vtm/userguide/session-persistence-with-udp-protocols
docTags: 
createdAt: 2026-08-02T07:48:41.236Z
---

UDP protocols are not connection oriented, but you will often desire that UDP datagrams in the same session are routed to the same back-end server.

In the **Virtual Servers > Edit > Protocol Settings** page, the two settings **udp\_timeout** and **udp\_response\_datagrams\_expected** are used to inform the Virtual Traffic Manager what the UDP session should look like.

The UDP session lasts until the number of response datagrams observed is equal to the setting **udp\_response\_datagrams\_expected**. For example, if a session completes once the server has sent one datagram to the client, set **udp\_response\_datagrams\_expected** to "1".

If the session is long-lived, set **udp\_response\_datagrams\_expected** to "-1". The UDP session times out if no further UDP traffic has been observed within **udp\_timeout** seconds.

You can use Session Persistence of various types (typically IP-based or Universal) with UDP if you want to track sessions for longer periods of time.