Dear Cash Market participant,

While our constant effort is to keep the usual high availability rate of the Xetra T7 trading system, we want to support our trading participants to be prepared as best as possible for the rarely occurring incident cases. Therefore, we will start publishing newsflash messages on a regular basis that explain the handling of various special incident cases or provide more general incident handling information. 

Today, we provide you with the information needed, in case a delay in the matching engine processing takes place.

1.  Background information

Large processing delays in the T7 matching engine (caused e.g. by technical problems or unexpected extreme loads) may lead to the build-up of internally queued orders. 

To avoid processing of old orders and to quickly recover from this delay situation, the affected products change to an internal “not tradeable” state. This rarely occurring kind of incident is automatically detected and for the relevant products the following actions are taken: 

• All non-persistent orders and quotes are deleted. 
• The product is temporarily set to an internal “not tradeable” state. Session data and listener broadcasts are sent. The product is not set to “Halt”. 
• All transactions will be rejected except for order deletions, for a minimum time frame, which is currently configured to ten seconds and until the delayed processing is resolved.
• Once the situation is resolved, it will be communicated via session data and listener broadcasts.

2.  Best Practice

If an ETI trading session receives the message “Product_temporarily_not_tradeable”, submission of new orders should be avoided until the “Service Resumed” notification is received, since the new order flow will only exacerbate the solution of the delay problem and the orders will be rejected anyway.

Deletion of non-persistent orders and quotes already took place, so any clean-up can be limited to the deletion of persistent orders, if necessary.

3.  Focus days in Simulation

This focus day scenario is provided to assist participants in testing the very rare event, where massive processing delays occur on a partition.

For more details, please check the following documents on our Xetra website www.xetra.com:

• Participant Simulation Guide
  under the path: Technology > T7 trading architecture > System documentation > Release 8.1 (or latest release version) > Simulation
• Simulation Calendar
  under the path: Trading > trading calendar and trading hours

The latest news on the development and the implementation of T7 Xetra is available on our page

• Implementation News
  under the path: Technology > Implementation News

4.  Further information

For further information, on our Xetra website, please have a look at the

• T7 Incident Handling Guide (Chapter 3.6)
  under the following path: Technology > T7 trading architecture > System documentation > Release 8.1 (or latest release version) > Production

If you have any further questions or comments please do not hesitate to contact your Key Account Manager or send an e-mail to client.services@deutsche-boerse.com.

Kind regards,

Your Client Services Team