connecting t-mobile core network using cisco r4 … emulation over packet enables clock distribution...

Connecting T-Mobile Core Network Using Cisco R4 Architecture

© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 1

Cisco R4 Architecture

Viktor Nastev, T-Mobile Macedonia

T-Mobile Old Core Network

2

© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID

� T-Mobile MK new generation core network R4/5 must meet all the requirements regarding quality,

availability, reliability as well existing TDM based core network and ensure future evolution to all-IP.

It’s a fundamental step for T-Mobile MK to migrate voice services from traditional TDM transport

and Monolithic architecture to the more cost-effective and flexible IP transport launching new

distributed switching subsystem architecture.

� T-mobile MK core network involves 4 sites (Skopje, Veles, Bitola and Strumica) which have to be

connected in presented configuration (see Figure 1).

MSC-S 2

HLR2/

FNR2

MSC-S 1

HLR1/

FNR1

MGW3

MGW2

SKOPJE VELES

3


BSC3

SGSN GGSN

BSC1 BSC2

MGW4

BSC4

MGW6

BSC6

BITOLA STRUMICA

Backbone Network

MGW1

Figure 1. TM MK Network

T-Mobile New Core Network

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Network Requirements

� Due to the constraints of the production traffic that will be carried, it is necessary to engineer theentire network to provide for the highest possible availability (99.999%). This is defined as networkconnectivity (i.e. an active path with sufficient capacity) between any two TMMK locations beingavailable not less than 99.999% of the time. The allowable outage figures includeincludeincludeinclude downtime forplanned, service affecting work.

� The network must also be capable of supporting IP QoS using both differentiated services andMPLS traffic engineering in order to ensure that the individual needs of all services can be met.

� The target time for fault detection and re-routing is <50ms.

� As the new network will be required to carry different services, with different traffic characteristicsand requirements, it is essential that a workable QoS model be deployed on the network from the

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and requirements, it is essential that a workable QoS model be deployed on the network from thebeginning

� Primary sites have been chosen as they have high data / voice requirements and for redundancy reasons .

� It is also important that the WAN design is created so that in the event of a failure, the extra distance that traffic has to travel does not mean that latency budgets for the core network are exceeded.

� Physical layer for WAN connections will be based on point-to-point links 1 Gbps Ethernet with availability of 99,99%, connecting PE routers between primary sites. The distance of Ethernet links will be max. 300 km and delay of less than 2 ms.

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GE

GEGE

GEGE

GE SR A

MGW

GE

GE

GE

GE

FE

FE

GE

GE

FE

FE

FE

FE

GE

GE

GE

GE

GE

GE

FE

FE

FE

FE

FE

FE

GE

GE

GE

GE

FE

FE

FE

FE

FE

FE

GE

GE

GPB

Main

SubrackO&M

GPB

Switch 1Nb

SS7O&M

SS7 VLAN A & Nb VLAN active

O&M VLAN

O&M VLAN

SS7 VLAN A

ET-MFG19

ET-MFG20

SS7 VLAN B & Nb VLAN standby

O&M VLAN

Typical MSS Core Network Site

7


GE

GE

GE

GE

SR BGE

GE

GE

GE

GE

GE

FE

FE

GE

GE

FE

FE

FE

FE

GE

GEG

E

GE

GE

GE

FE

FE

FE

FE

FE

FE

Switch 2

GE

GE

GE

GE

FE

FE

FE

FE

FE

FE

GE

GE

MSC-S

SLI

SLI

FE

APG40 O&M

Nb

SS7

O&M

FE

SS7 VLAN B

O&M VLAN

O&M VLAN

SS7 VLAN A & Nb VLAN standby

SS7 VLAN B & Nb VLAN active

FE

APG40 O&M

FEO&M VLAN

Cisco IP NGN Transport Products

Low Bandwidth

Aggregation

PE

High Bandwidth

AggregationPE

CoreP

IP Solution Center

Management

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Cisco XR

12000 SeriesCisco 7304Cisco 7600

Series

Cisco CRS-1 MC

88

Cisco CRS-1 4/SCisco 7200

2 Mpps 3.5 Mpps 30+ Mpps 300+ Mpps 1+ Tpps

Cisco IP NGN Transport FeaturesSolving All-IP Challenges

� Reliability (99.999%, <200ms failover, delay, jitter)Reliability (99.999%, <200ms failover, delay, jitter)Reliability (99.999%, <200ms failover, delay, jitter)Reliability (99.999%, <200ms failover, delay, jitter)

� High-availability features – SSO, NSF

� Fast convergence features – IGP-FRR, TE-FRR, BFD

� Flexible QoS for delay and jitter requirements

� Resource reservationResource reservationResource reservationResource reservation

� MPLS-TE – based on Traffic Class reservations can be made

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� Strict QoS features ensure quality for voice traffic

� Call admissionCall admissionCall admissionCall admission

� Cisco participates in standardization efforts for Bandwidth Manager (controlled by MSC-S)

� However, the limitation is mostly on the MGWs

� Clock distributionClock distributionClock distributionClock distribution

� Circuit Emulation over Packet enables clock distribution over MPLS

Cisco IP NGN Transport Added Value

� IPv6IPv6IPv6IPv6

Support for IPv6 VPNs

� MulticastMulticastMulticastMulticast

Support for multicast over MPLS

Enables new services

�

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� Integration of existing corporate networkIntegration of existing corporate networkIntegration of existing corporate networkIntegration of existing corporate network

Use common MPLS core for corporate traffic

Use QoS to avoid impact on customer traffic

� Cisco 7600 platform for other applicationsCisco 7600 platform for other applicationsCisco 7600 platform for other applicationsCisco 7600 platform for other applications

ITP

GGSN

Load-balancing

MSC server

SGSN Gs

GGSN GMSC

server

Gn HLR

Gr

Gc C

D

Nc

H

EIR

F Gf

Gi PSTN

VLR B

Gp

VLR

G

MSC server

B

PSTN

CS-

MGW

AuC

Nb

Mc Mc

PSTN PSTN

Nc

Mc

E

3GPP Release 4 – Main Changes

Changes

Circuit Core Split Architecture

� signaling separated from user traffic� Media Gateways responsible for transcoding and transporting voice traffic� MSC Servers are responsible for signaling and control of MGWs� IP as option for transport

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BSS

BSC

RNS

RNC

CN

Node B Node B

IuPS

Iur

Iub

USIM

ME

MS

Cu

Uu

IuCS

BTS BTS

Um

RNC

Abis

SIM

SIM-ME i/f or

cell

CS-MGW CS-MGW

Mc Mc

Nb

A Gb

(1 some components can support SIGTRAN directly

3GPP TS 23.002

Signaling over IP

� IP as option for SS7 transport� Signaling Gateways introduced between legacy SS7 and SS7oIP networks

IP option for Iu-PS/Iu-CS/Gb

� IP as option between RNC/RNC and SGSN� IP as option between RNC and MGW� A remains TDM

MPLS Core

IP NGN Transport for 3GPP Release 4

CN

MSC server

SGSN Gs

GGSN GMSC

server

Gn HLR

Gr

Gc C

D

Nc

H

EIR

F Gf

Gi PSTN

VLR B

Gp

VLR

G

MSC server

B

PSTN

CS-MGW CS-MGW

CS-

MGW

AuC

Nb

Mc Mc

Nb

PSTN PSTN

Nc

Mc

E

Transport

Gn/Gp/Gi (GPRS User Plane)� classical IP interfaces� Map to appropriate VRFs on the MPLS Core

Nb/Nc/Mc (CS User and Control Plane) � Transport Option IP:

� Mapped to VRFs on the MPLS Core� Ethernet Access Interfaces

C/D/F/Gf/Gr/Gs (SS7 Interfaces)� Classical SS7 Option

� use CEoP (Circuit Emulation over Packet) or ATMoMPLS

� SIGTRAN Option� use Cisco ITPs as SS7 to SIGTRAN gateways(1

� map SIGTRAN traffic to VRF

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IP AccessIP Access

BSS

BSC

RNS

RNC

Node B Node B

IuPS

Iur

Iub

USIM

ME

MS

Cu

Uu

IuCS

BTS BTS

Um

RNC

Abis

SIM

SIM-ME i/f or

cell

Nb

A Gb

� Ethernet Access Interfaces� Transport Option ATM:

� ATMoMPLS PWs

� ATM Access Interfaces

Iu-CS/Iu-PS/A/Gb (User and Control Plane)� ATMoMPLS PWs for ATM based interfaces� FRoMPLS for Frame-Relay based interfaces� CEoP for SDH/PDH based interfaces� Native IP for IP option of Iu-PS, Iu-CS or Gb

Abis/Iu (User and Control Plane)� RAN-Optimization portfolio � ATMoMPLS PWs for ATM based interfaces� FRoMPLS for Frame-Relay based interfaces� CEoP for SDH/PDH based interfaces and clocking

(1 some components can support SIGTRAN directly

3GPP TS 23.002

T-PE

End-to-End

VoIP

L3 VPN

Edge Domain ProtectionIP routing, HSRP, BFD

Edge Domain ProtectionIP routing, HSRP, BFD

Core Domain ProtectionFast IGP, MP-iBGP, TE FRR

L2 SWL2 SW

T-PE

R4 Site structure and IP / MPLS Core Connectivity

CS domain interconnection at L2 or L3

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MGW

T-PE

Core Domain Control PlaneIP / MPLS (IGP,LDP, MPLS VPN, L2 VPN)

Edge DomainGE, ATM

Edge DomainGE, ATM

MGWT-PE L2 SW

L2 SW

L2 SW

T-PE

RNC

T-PE

T-PE

L2 VPN

End-to-End

ATM

T-PE

IP / MPLSATM

Summary

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� As voice revenues are decreasing we have to offer more and more data services to our

subscribers

� Voice increase YoY is 40 - 50 %

� Data increase is even more significant

� The trend in the industry is to implement native IP interfaces for transmission on all core

network elements

Summary

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network elements

� It is too expensive to build 2 independent transmission networks

(one for DATA and one for VOICE)

� Having in mind the transmission capacities needed in future it is more adequate to build

IP network for the transmission

� As VOICE is still responsible for biggest part of the revenue it is necessary to build the

IP network in such a way that the voice as such will not suffer in any way

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