Add RedHat ERN details

docs/support/redhat.md

@@ -68,3 +68,29 @@ Users of the [linux-announce-rhel](https://e-groups.cern.ch/e-groups/Egroup.do?e
 
 In order to open a ticket, ask if a colleague added your account for RedHat support (as part of the onboarding steps), you can report cases on <https://access.redhat.com/support/cases/>
 
+## Extended Research Network (ERN)
+
+* As part of the CERN's academic site license, we negogiated special conditions for HEP sites as part of a "Extended Research Network" (ERN) whereby sites affiliated with CERN for "research" can get up to 1000 RHEL licenses for zero cost
+* Interested sites need a commercial agreement with Red Hat (although one can be created at the time of interest) and an "introduction" through CERN (See [Red Hat Contacts](#Red Hat Contacts) above)
+* Larger HEP sites can also apply directly to Red Hat for a Site License agreement
+
+!!! note ""
+    Research: servers exclusively doing computations, analysing and storing research data. HPC, Big data
+    Non-research: computing capacity required to run organisation’s backend systems such as email servers, file servers storing various documents, HR, ERP, backup servers etc
+
+This information has been shared with the HEP community several times, the most recent being the [Update on the Linux Strategy for CERN (and WLCG)](https://indico.cern.ch/event/1222948/contributions/5321042/attachments/2618936/4527498/20230328-hepix-linux-update.pdf) presentation at HEPiX Spring 2023
+
+If a HEP site contacts us asking to profit from this offer, all we need to do is forward the request email to our [Red Hat Contacts](#Red Hat Contacts) - indicating that the institution is affiliated with CERN for the purposes of research. If you do not know who/what the institution is, it's best to check if they have [signed a MOU](https://wlcg.web.cern.ch/mou/signed) which indicates that the site is contributing to CERN via WLCG resources in some capacity.
+
+Here is a list of the sites that we assume have so far profited from this agreement.
+
+!!! note ""
+    CERN is only involved in the initial onboarding, we don't know any specifics about how the contract is implemented
+
+| Date site contacted CERN | Institution                                       | Institution contact name     |
+| ------------------------ | ------------------------------------------------- | ---------------------------- |
+| 2023.06.08               | Istituto Nazionale di Fisica Nucleare (INFN)      | andrea.chierici@cnaf.infn.it |
+| 2023.05.30               | Institut de Physique des 2 Infinis de Lyon (IP2I) | d.pugnere@ipnl.in2p3.fr      |
+| 2023.01.11               | Helsinki Institute of Physics (HIP)               | tomas.linden@Helsinki.fi     |
+| 2022.06.27               | TRIUMF                                            | di.qing@cern.ch              |
+