Diameter Routing Extensions
(draft-tsou-dime-base-routing-ext
-03.txt)
tena@huawei.com ; vfajardo@toshiba.com
jouni.korhonen@teliasonera.com ;
tasveren@sonusnet.com
IETF70 DIME WG
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Overview
• Refresher
– Ability for intermediaries to stay in the Diameter
signaling path during a session (e.g. an outgoing
gateway for a domain enforcing policy)
• Updates since IETF 68/69
– Proposes new “workarounds” to provide explicit
routing without using new routing AVPs
• Introduce intermediate proxy nodes that are session stateful
• Session stateful nodes can select the next hop node to send
session messages to
– Retain old scheme
• Use new routing AVPs that keep track of nodes to visit
– Added more use case scenarios; i.e. 3GPP
IETF70 DIME WG
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Comparisons of current explicit routing schemes
•
Stateful node acting as diameter back-to-back server-relay
– Advantage
• Can be used without adding/changing AVPs in messages; easily backward compatible
• Back-to-back server retains the burden of maintaining session-based routing scheme
• End-point receivers (and maybe transmitters) of the messages need not know about
explicit routing
• Requires that the back-to-back server acts as separate Diameter server for all
service/domain pairs
• If security procedures on application level are employed, the back-to-back server should
proxy them
– Disadvantage
• An agent that is not stateful and residing one-hop or more prior to the stateful proxy
node can re-route session messages away from the stateful proxy
• Requires that the back-to-back performs endpoint procedures, e.g. duplicate detection
•
Use of routing AVPs
– Advantage
• Nodes that need to be visited are explicitly tracked from end-to-end
– Disadvantage
• Requires new routing AVPs to be piggybacked on session messages
• Requires support from all participants (sender, intermediate nodes and receiver)
IETF70 DIME WG
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Use case #1: TISPAN NASS
Visited NGN network
Home NGN network
Service control subsystems
Home NGN
Access Network
Visited NGN
Access Network
e2
Resource and
Admission
Control
Subsystem
e4
a2
CLF
a4
PDBF
e5
NACF
a1
a3
CPE
UE
(CNG/TE)
UAAF
UAAF
UAAF
UAAF
UAAF
UAAF
UAAF
UAAF
e1
e1
ARF
AMF
Access Transport network
•E5 interface is a diameter cloud which typically has relays
•For each sessions, a3 can use any available UAAF
•Problem: Server messages (Home to visited) for a session
needs to pass through the same UAAF in the visited network
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Use case #2: 3G I-WLAN
Intranet / Internet
3GPP Visited Network
Wa
WLAN Access Network
WLAN Ww
UE
Wg
WAG
Offline
Charging
System
Wp
3GPP AAA
Server
Wo
HLR
OCS
Wz
•Wd interface is a diameter cloud which typically has relays
•For each sessions, Wd can use any available 3GPP AAA Proxy
•Problem: 3GPP AAA Server messages (Home to visited) for a session
3GPP Home Network
needs to pass through the same 3GPP AAA proxy in the visited network
IETF70 DIME WG
•Problem: Current 3GPP scheme uses decorated NAI in the User-Name
to define a type of source routing
Wi
HSS
f
Wy
W
Packet Data
Gateway
m
SLF
r'
/G
W
Dw
Wx
D'
Wu
WLAN 3GPP IP Access
Wd
Wn
3GPP AAA Wf
ProxyAAA
3GPP
ProxyAAA
3GPP
Proxy AAA
3GPP
Proxy
Offline
Charging
System
5
Use Case #3: Diameter MIPV6 Application
Mobility Service
Authorizer
Mobility Service
Provider
IKEv2-EAP
Home
Agent
AAA
Cloud
AAA-MSP
Server
AAA-MSP
Server
AAA-MSP
Server
AAA
Cloud
AAA-MSA
Server
•Multiple AAA-MSP can exist in the service provider network
•Diameter clouds can contain stateless relays
Problem: Server messages (Authorizer to provider) for a session
needs to pass through the same MSP in the provider network
IETF70 DIME WG
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