Cisco Cisco Prime Network Registrar 8.0 White Paper

 

 

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White Paper 

Cisco Prime Network Registrar - DNS in Mobile 
Networks 

IP communications between service providers today are starting to evolve to support 
services other than General Packet Radio Service (GPRS) roaming. These new 
services rely upon Domain Name System (DNS) for inter-Public Land Mobile Network 
Multimedia Messaging Service (PLMN MMS) delivery and IP Multimedia Subsystem 
(IMS) interworking. Therefore, it is of utmost importance for service providers to 
choose the most resilient and reliable DNS solution to ensure that their customers 
experience seamless roaming and uninterrupted internet connectivity. 

This document is intended to provide guidelines and technical information for those who need to set up or maintain 

DNS servers for inter-service-provider services with Cisco Prime

™

 Network Registrar. 

DNS as Used in an MPC/EPC Network

1

 

The Domain Name System is critical to such services as GPRS roaming, inter-PLMN MMS delivery, and IMS 

interworking. DNS is defined in many IETF RFC documents; the most notable ones are IETF RFC 1034 [1] and 

IETF RFC 1035 [2]. The DNS on the inter-PLMN IP backbone network (known as the "GRX/IPX") is completely 

separate from the DNS on the Internet. This is purposely done to add an extra layer of security to the GRX/IPX 

network and the nodes within it. 

The GRX/IPX root DNS servers that network operators see are known as "slave" root DNS servers and are 

commonly provisioned by a service provider's GRX/IPX service provider. See Figure 1. However, operators 

themselves can provision these slave root DNS servers if they so wish by making a copy of the GRX root server 
records in their own network. The “master” root DNS servers are managed by the 

 and 

have no relationship to the 13 root name servers ([a-m].root-servers.net.) used by all Internet DNS users.