Lately the subject of ShoreTel Route Points and IRN’s has been getting a lot of “mind share” from those working with them.   Two questions:  How many Route Points can a ShoreTel server support?  How many IRN’s can an ECC support?  How many DNIS numbers can a ShoreTel support.   Seems like a simple set of questions, but the answers are something like “herding cats”.    Route Points are used in a ShoreTel system to accomplish call routing and TAPI connectivity between the IPBX and the Enterprise Contact Center, for example.   Let us assume, for purpose of illustration, that you have a large call center and you want to track the effectiveness of your advertising campaigns.   You determine to do this by tracking DNIS numbers.  Each DNIS represents a different advertising campaign.  Recently, I came across a client who was creating a route point – IRN pair for each DNIS number.   Nothing particularly wrong with this, but using the DNIS map would have required only one Route Point if the DNIs was pointing to the same Group of Agents (e.g. Service) in the Contact Center. The Contact Center, currently can only map one DNIS number per IRN.  It is my understanding that ShoreTel may be moving toward 1000-1500 DNIS numbers in future ECC releases.  So if you want to run report about DNIS you might have to look in two databases: (a) the ShoreTel MySQL CDR database on the IPBX; and (b) the C2G database on the ECC.  You will need to use the GUID if you want to tie the two databases together to get the DNIS and Agent Events and Wrap codes.   If you bring the DNIS into the IRN,  to enable DNIS reporting in the ECC, you can see the list of IRN’s could get very long and there is a  limit. I suspect that DNIS has a limitation as well.  My thinking is that DNIS numbers would live in the various SG switches.  So the ultimate answer to how many DNIS numbers you can have may be memory constraint and  configuration specific (e.g. different for each configuration).    If you have any input on this, I would welcome it!   At the end of the day what we know is that you can create Route Points all day long in ShoreTel (though I have not attempted to find the real limit).  If the Route Points live on the ShoreTel server the real limitation is the 254 simultaneous media streams that a Microsoft Server can support.   If you point 12 PRI’s at one server and you have the potential of having 276 simultaneous phone calls, bad things are going to happen.   You need to spread your media stream over multiple servers.   In the contact center, you generally shape media streams (e.g. IVR ports) to 150 per server. The “devil is in the details”.