Status and challenges for practical implementation

of synchronization in a NGN network seen from a

Telecom Operator’s perspective

Sverre Bjønnes, Telenor Norway

Contents

1. Implementation of SyncE in the Telenor Core network in Norway for frequency

synchronisation.

2. Status for implementation of 1588v2 for frequency synchronisation

3. Challenges for an existing operators network when phase-synchronization is

introduced for LTE-A/LTE-TDD

2

3

Implementation of SyncE in the Telenor Core network in

Norway for frequency synchronisation.

Implementation of SyncE in the

Norwegian Core network for frequency

synchronisation.

• NEs used in SDH-Core are

the oldest SDH-NEs and

should be replaced (>15y)

• Old STM-16 SDH-rings

which is carrying sync are

nearly emptied.

4

From sync

distribution in SDH CORE

5

PRC

R11

CC11

R12

R2m

CC12 CC13

R22 R21

CC21

R3o

CC22 CC23 CC2n

R3m R3m R3m SEC (G.813)

SEC (G.813)

SSU (G.812)

PRC (G.811)

Will be removed first

Will be removed later

Cross Connect w/ G.812

SDH ring

SSU (G.812)

SEC (G.813)

• NEs used in SDH-Core are

the oldest SDH-NEs and

should be replaced (>15y)

• Old STM-16 SDH-rings

which is carrying sync are

nearly emptied.

• Traffic are moved to IP over

WDM.

• IP network are chosen as

carrier for synchronisation

6

From sync

distribution in SDH CORE

To SyncE

distribution in Telenor MPLS and IP/VPN CORE

network

Implementation of SyncE in the

Norwegian Core network for frequency

synchronisation.

• Test to be executed with SyncE from PRC in Oslo to IP nodes with GPS

reference in Tromsø (1966 km fibre + 14% delay due to DCMs).

• SASE (G.812 clocks) to be used between SyncE distribution in Core

and sync input via SDXC to the regional SDH network

7

SyncE distribution in Telenor MPLS and IP/VPN CORE network

Sync distribution from IP Core Network to SDH regional network

8

Status for implementation of 1588v2 for

frequency synchronisation

Mobile network with IEEE-1588v2 sync distribution -

frequency.

• Green: 6 hops minimum + MPLS-core

• Red (Fault situation): 11 hops maximum + MPLS-core

9

MSS

MSS

MSS MSS

MSS

MSS

BNG

BNG

MPLS/IP

Network BNG RSS

IPClk / GM

CSS CSS Node B/OC Node B/OC

Metro-ring (MPLS/IP)

MSS – Metro Site Switch

Supports TC and BC

CSS – Cell Site Switch

BNG - Broadband Network Gateway

Supports SyncE

RSS - RNC Site Switch

(RNC = Radio Network Controller)

10

Challenges for an existing operators network when

phase-synchronization is introduced

for LTE-A / LTE-TDD

Mobil network

with IEEE-

1588v2

Green: 2-fiber WDM system

Red: 1-fiber CWDM system or BiDi SFP

Blue: Micro-wave system (No adaptive modulation used)

11

MSS

MSS

MSS MSS

MSS

MSS

BNG

BNG

MPLS/IP

Network BNG RSS

IPClk / GM

CSS

CSS

Node B Node B

Metro-ring (MPLS/IP)

(up to ~600 km)

x

Node B

Node B

CSS

CSS

CWDM

CWDM

CWDM

MSS

Mobil network

with IEEE-1588v2

for phase-

synchronisation

• Introduction of BC with SyncE support will:

• Reduce the number of clients to be connected towards GM

• Reduce the number of hops from Node B to nearest master

• Crypto between Node B and BNG. PTP packets not available between Node

B and BNG. TC/BC in MSS not available!

• Layer 3 and preferably also multicast have to be activated to use TC/BC in

Metro-ring

12

MSS MSS

MSS MSS

BNG

BNG

MPLS/I

P

SyncE BNG RSS

IPClk / GM

CSS

CSS Node B Node B

Metro-ring (MPLS/IP)

(up to ~600 km)

Node B

Node B

CSS

CSS

BC

BC MSS

Requirements for adjacent clusters using different parts of the transport network

providing timing for LTE-A with or without CoMP (coordinated multipoint)

13

MPLS/IP

SyncE BNG RSS

IPClk / GM

MSS

MSS

MSS MSS

MSS

MSS

BNG

BNG

CSS CSS

Node B Node B

Metro-ring 1 (MPLS/IP)

x

Node B

Node B

CSS

CSS

CWDM

CWDM

CWDM

MSS

MSS

BNG

Metro-ring 2 (MPLS-IP) CWDM

MSS

BNG

MSS

Node B

Node B

CSS

CSS

?

? ? ?

?

BC

BC

BC

BC

Core Network

operator serving

multiple

Mobile Operators

• Mobile operator owns GM and provides timing for his own purpose

• Requirements for the Core Network

• BC at BNG will have support for SyncE

• TC at Metro-Ring is desirable, but will have problems due to Crypto and MPLS 14

MSS

MSS

MSS MSS

MSS

MSS

BNG

BNG

MPLS/IP

SyncE BNG

RSS Operator 1

IPClk / GM

CSS

Node B2

Metro-ring (MPLS/IP)

CSS

RSS Operator 2

Node B1 Node B2 Node B1

BC

BC IPClk / GM

BC

BC

Core Network

operator serving

multiple

Mobile Operators

• Network operator owns GM and provides timing

15

MSS

MSS

MSS MSS

MSS

MSS

BNG

BNG

MPLS/IP

SyncE BNG

RSS Operator 1

IPClk / GM

CSS

Node B2

Metro-ring (MPLS/IP)

CSS

RSS Operator 2

Node B1 Node B2 Node B1

BC

BC

Summary

• This presentation is made in order to point out challenges for an operator to

support phase-synchronization.

• New infrastructure just installed for IP/MPLS Core and IP mobile backhaul.

Short term solutions should be based on existing hardware!

• LTE-A, LTE-TDD and LTE-A CoMP

Which phase-requirements will be relevant for the Network to serve different

sizes of radio sub-networks?

• Implementation of TC and BC in MPLS-networks is a challenge

• CRYPTO when used is a challenge as traffic- and sync-packets use the same

VPN between Node B and a «CRYPTO-Box»

16

Thank you