Listened to XO to introduce Enterprise SIP (ESIP) to the Channel today. This offering is very targeted. Enterprise SIP is designed for multi-location customers such as Retail and Restaurant chains that are looking to get rid of PRI's.  

ESIP will be for high capacity connections with the minimum connection of 10MB at the hub (or HQ) for aggregated voice traffic. 

Essentially it is a SIP trunk (at 10MB) that will take all of the local and long distance traffic - inbound and outbound - from the branch offices across an MPLS (or other private network) through one or two hub circuits. 

Here's how it works.

You connect all of the offices together via a private network or MPLS architecture. Then you port all of the numbers to the SIP Trunking of XO's Enterprise SIP Service. The trunk will plug into an IP-PBX or an SBC and handle all of the voice traffic on the company network. All inbound and outbound voice traffic will utilize the ESIP Trunk.

A 10MB pipe will handle about 100 G.711 call streams (more or less). That means about 500 to 1000 extensions depending on the phone usage of the employees.

XO will even give Virtual-NXX numbers off this trunk. Although toll bypass is not allowed. 

The thing that surprised me the most was how specific the offering is. It's isn't for everyone. It was designed with a very particular market segment in mind - namely retail and restaurant chains.

The ESIP offering is designed to terminate on a Session Border Controller, IP-PBX or a Fax Server. 

Need to UPDATE that this is my take-away from the call. XO has many VoIP products and they want to match up the best solution for each customer. The ESIP is specifically for Multi-Location, MPLS-enabled customers. Not many companies need or can afford a Session Border Controller, so to me that is an indicator of the type of Enterprise that this offering i sdesigned for.