Understanding some LTE terms

 IMSI: International Mobile Subscriber Entity

 

 

IMSI is composed of three parts:

1. Mobile Country Code (MCC)consisting of 3 digits. The MCC identifies uniquely the country of domicile of the mobile subscriber;

   2. MobileNetworkCode (MNC)consisting of 2 or 3 digits for GSM/UMTS/LTE applications. The MNC identifies the home PLMN of the mobile subscriber. 

The length of the MNC (two or three digits) depends on the value of the MCC.

 A mixture of two and three digit MNC codes within a single MCC area is not recommended. 

 

3. Mobile Subscriber Identification Number (MSIN) identifying the mobile subscriber within a PLMN.

 

Example IMSI:

234150999999999

• MCC = 234 (UK)
• MNC = 15 (02 UK)
• MSIN = 0999999999

 

           -15 digit number

           -Also associated with GSM and UMTS

           -It uniquely identifies every user of cellular network  

           -IMSI is stored inside the SIM

 

           - When mobile stations are powered on, they perform a location update procedure by indicating their IMSI to the network. The first location update procedure is referred to as the IMSI attach procedure.

 

 

HSS 

Home Subscriber Server

 

 

-Carried forward from GSM and UMTS

-Contains  profile and authentication information about all the subscribers of network operators

-The database stores information about subscribers to help in the authorization, details of devices, as well as the user’s location and service information. The HSS relays this information to the network using Diameter protocol, communicating with the Mobility Management Entity (MME) via the S6a interface. Combined with an Authentication, Authorization, Accounting (AAA) server, the HSS ensures that an LTE network works with legacy or concurrent services.

-The HSS also has the capability to communicate with a WiFi infrastructure, which gives operators the ability to generate revenue streams with the creation of WiFi hotspots and WiFi offload.

-Can also communicate with I-CSCF for supporting VOLTE calls

 

 

APN

Access Point Name

 

 

 -An identifier that lives in the LTE core network, otherwise known as the Evolved Packet Core (EPC)

-the APN identifies a Gateway GPRS Support Node (GGSN) or Packet Data Network GateWay (P-GW). 

- is the virtual private network (VPN) that connects the user equipment through the Packet Data Network Gateway (P-GW) to the Packet Data Network (PDN). User equipment can access many APNs, which are domain names and associated parameters, and one is the default APN. APNs are very similar to MPLS VPNs in landline networks.

-The APN identifies the packet data network (PDN) that a mobile data user wants to communicate with. In addition to identifying a PDN, an APN may also be used to define the type of service, (e.g. connection to Wireless Application Protocol (WAP) server, Multimedia Messaging Service (MMS)) that is provided by the PDN.

-e.g 1: internet.apn.epc.mnc012.mcc345.3gppnetwork.org 

 e.g.2:

Data APN settings:

• Name: T-Mobile US LTE
• APN: fast.t-mobile.com
• Proxy: <Not set>
• Port: <Not set>
• Username: <Not set>
• Password: <Not set>
• Server: <Not set>
• MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
• MMS proxy: <Not set>
• MMS port: <Not set>
• MMS protocol: WAP 2.0
• MCC: 310
• MNC: 260
• Authentication type:<Not set>
• APN type: <Not set> OR Internet+MMS
• APN protocol: IPv4/IPv6
• APN roaming protocol: IPv4
• Enable/disable APN: <greyed out unless there are multiple APNs>
• Bearer: Unspecified