Presentation from December 18, 2002 on Diameter and it's use in 3G networks

1. Diameter and Diameter Roaming
John Loughney
Research Manager
Nokia Research Center
john.loughney@nokia.com
1 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

2. AAA & Diameter
• Next generation Authentication, Authorization & Accounting
protocol
• Consists of base specification and applications
• MIP
• Network Access Server (Dial-up / PPP / SLIP environment)
• SIP Services
• Accounting Extensions
2 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

3. Standard RADIUS Model
3 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

4. Diameter Roaming
4 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

5. How It Works
• The user requests service from the remote ISP, which in tern
requests the user’s credentials.
• The user submits ID, password and address of his home-
agent. The remote server performs mutual authentication with
the home-agend and forwards the user’s credentials.
• The home-agent accepts the user’s credentials and then tells
the remove ISP to grant access to the user.
• Subsequently, the two ISPs update their call accounting
records.
5 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

6. AAA Elements
• Diameter Node
• A host that implements the Diameter protocol, and acts either as a
Client, Agent or Server.
• Broker
• A business term used in AAA infrastructures. A broker is either a relay,
proxy or redirect agent, and operated by roaming consortiums.
• Diameter Agent
• A host that provides either relay, proxy, redirect or translation services.
• Diameter Client
• A device at the edge of the network that performs access control. An
example of a Diameter client is a Network Access Server (NAS) or a
Foreign Agent (FA).
• Diameter Peer
• Node to which a given Diameter Node has a direct transport connection.
• Diameter Server
• A server that handles authentication, authorization and accounting
requests for a particular realm.
6 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

7. Diameter Connections and Sessions
Server relay Server
Peer connection A Peer connection B
User session X
7 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

8. Translation of RADIUS to Diameter
RADIUS Req Diameter Req
Translation Home
NAS
RADIUS Ans Agent Diameter Req Server
8 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

9. Diameter Proxy Example
local service home service
provider provider
Primary Primary
Proxy Home
Server Server
Network
Access
Server
Backup Backup
Proxy Home
Server Server
9 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

10. Diameter Extensibility
• Diameter tries to preserve Radius -like flexibility
• Diameter base commands and AVPs defined in the base spec
• Diameter extension can define new commands and AVPs.
• Examples are:
• NASREQ
• MOBILE-IP
• 3GPP Credit Control
• 3GPP Multimedia Application
• New AVPs can be added
10 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

11. AAA-SIP in 3GPP Rel. 5
Diameter
SLF HSS AS
Sh
Diameter ISC
Dx Cx Cx
Diameter
Gm Mr
Mw Mw
UE P- I- S- MRFC
CSCF CSCF CSCF
Megaco
Compression Mi
COPS for
Go SIP MRFP
Policy Control
GGSN
Mj
BGCF MGCF SGW
SIP SIP-ISUP
Megaco Mc
Visited Home
Domain Domain
MGW
11 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

12. Work to Do
• Diameter Base Specification just submitted.
• Diameter Mobile IPv4 Application nearly ready (needed by
3GPP2).
• Diameter NASREQ Application nearly ready.
• CMS Security Application, needed for e2e security
• AAA Key Distribution
• SIP-AAA Requirements
• Diameter Mobile IPv6 Application
• Diameter Multimedia Application (3GPP rel. 6)
• Diameter Credit Control Application (3GPP rel. 6)
12 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

13. Summary
• Integrating different access technologies (3G, WLAN, DSL,
Dial-up):
• increases the potential for increasing subscribers.
• increases accesses to services.
• Integrating/harmonizing signaling:
• harmonizes network infrastructure.
• simplifies network management.
• simplifies charging/billing.
• simplifies the user experience.
13 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney

14. More Info
• http://www.diameter.org/
• I will be heading an NRC program
• Access Independent AAA Infrastructure
14 © NOKIA diam-roam.PPT/ 18 December 2002 / John A. Loughney