Multi-operator connection issues
in GRX networks
GPRS/UMTS roaming
Annikki Welin Ericsson research
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Introduction
• The end-to-end transport of telecom services often involves multiple carriers
• Mobility makes roaming and interworking important
• Interworking
- We have to agree and standardize common minimal set of requirements to
be able to transport end-to-end services
• Resource optimization of across E-NNI (AS) boundaries
• QoS guaranties across E-NNI (AS)
• Fast protection along the (VPN) path
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Home GGSN Roaming Example
Root
DNS
SGSN
Border
Gateway
Visited
Operator
Inter-PLMN
GPRS Backbone
Visited Operator
Intra-PLMN
GGSN
GGSN
Visited
DNS
Internet
Border
Gateway
SGSN
Home Operator
Intra-PLMN
Home
Operator
Home
DNS
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Direct connectivity between GPRS operators
• IPSec
Using Internet as transport
• Frame relay , ATM
Leased line as transport
• VPN
Using ATM, Sonet/SDH or wavelength as transport
Requirements are
Security and QoS
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Connections to the GRX Network
•
•
•
GRX = GPRS Roaming Exchange
Several types of connections to the GRX
network is available
BGP routing between carrier and GRX
provider
Connection to other
GRX operators
GRX
Layer 3
BG
IPSec VPN tunnel
Layer 2
Carrier x
Frame Relay/ATM/Ethernet/SDH
Layer 1
BG
Leased line
Carrier Y
BG
Carrier Z
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MPLS in the GRX - L3 VPN
VPN A
VPN A
CE
PE
VPN B
CE
PE
P
GRX
Netwrok
VRF
P
VPN B
PE
CE
VRFs
P: Provider Router
PE: Provider Edge Router
CE: Customer Edge Router
VRF: VPN Routing & Forwarding
•
•
•
VRF
CE
PE routers maintain multiple routing tables
– one VRF per connected VPN
– interface mapped to VPN
MBGP used for routing updates
MPLS LSPs used for transport
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MPLS in the GRX – L2 VPN
GRX network
FR
FR
LSP
ATM
PE
FE/GE
•
•
PE X
ATM
PE
PE Y
FE/GE
Supports multi-protocol from CE site
Circuit type must be the same on ingress and egress
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Layer one connection Point-to-Point
•
Leased line
ATM. FR. IP
Customer
Edge
GRX network
• Fibre or
wavelength
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Common requirements for all type of connections
•
•
•
•
•
•
Protection
Security
Service garantees CoS/QoS Packet loss
Policies
Signalling/VLANs
Addressing
•Network management requirements
• Monitoring
• Alarms
• Static's
• Event-log
• Filters
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VPN network management issues
• Resource monitoring in VPN tunnels
How to monitor ?
• tunnel head
• tunnel tail
• transfer entries
• QoS resources
• Timers (hello intervals)
• Errors between boundaries
Could distribute management system be the solution?
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Transit VPNs
E-NNI between GRX-networks ?
Central Exchange point
Central Exchange point
GRX-to-GRX
GRX
OXC
X
Central Exchange point
GRX
OXC
GRX-to-GRX
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Conclusions and questions
• The problems are similar at GMPLS and VPNs with
inter-carrier / PLMN connections
• Will MPLS VPNs continue through carrier boarders?
• SLA at L1, L2 or L3
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