transmission network design and architecture guidelines version 1 3

7/27/2019 Transmission Network Design and Architecture Guidelines Version 1 3

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Transmission network planning__________________________________________________________________________

Transmission network design

& architecture guidelines 13/06/2013 Page 1 of 64

Reference: Transmission network design & architecture guidelines

Version: 1.3 Draft

Date: 10 June 2013

Author(s): David Powders

Filed As:

Status: Draft Version (1.3)

ApprovedBy:

Signature /Date:

.......................................................... / ......................

NSI Ireland

Transmission NetworkDesign & Architecture

Guidelines

Version 1.3 Draft


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Document HistoryVersion Date Comment

1.0 Draft 27.01.2013 First draft

1.1 Draft 25.02.2013 Incorporating changes requested from parentoperators;- Resilience- Routing- Performance monitoring

1.2 Draft 14.05.2013 - Updated BT TT Routing section 2.3

1.3 Draft 10.06.2013 - Section 2.3 E-Lines added to TT design- Section 2.6 Updated dimensioning rules- Section 2.6.4 Updated Policing allocation per class- Section 3.x added (Site design)

Reference documents1 (2012.12.27) OPTIMA BLUEPRINT V1.0 DRAFT FINAL.doc

2 Total Transmission IP design - DLD V2 2 (2)[1].pdf


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Contents

DOCUMENT HISTORY ....................................................................................................... ................ 2REFERENCE DOCUMENTS......................................................................... ...................................... 21.0 INTRODUCTION.............................................................................................. ........................... 5

1.1 BACKGROUND............................................................................................................................. 51.2 SCOPE OF DOCUMENT................................................................. ................................................. 51.3 DOCUMENT STRUCTURE.............................................................. ................................................ 5

2.0 PROPOSED NETWORK ARCHITECTURE ............................................................... ................ 62.1TRANSMISSION NETWORK............................................................... ................................................ 72.1DATA CENTRE SOLUTION................................................................ ................................................ 8

2.1.1 Physical interconnection ........................................................ ................................................ 82.2SELF BUILD BACKHAUL NETWORK............................................................ ...................................... 9

2.3.1 Self build fibre diversity ....................................................................................................... 122.3MANAGED BACKHAUL .................................................................................................................. 13

2.3.1 TT Network contract ........................................ .............................................................. ...... 132.3.3 Backhaul network selection.............................. ................................................................. ... 16

2.4 BACKHAUL ROUTING ................................................................................................................ 162.4.1 Legacy mobile services .................................... .............................................................. ...... 162.4.2 Enterprise services ................................................................. .................................... 172.4.3 IP services ......................................................... ......................................................... 17

2.4.3.1 L3VPN structure ............................................................................................................... 172.4.3.2 IP service Resilience........................................................................................................ 19

2.5 ACCESS MICROWAVE NETWORK........................................................... .................................... 202.5.1 Baseband switching ................................................................................................ ... 212.5.2 Microwave DCN .......................................................... .............................................. 222.5.3 Backhaul Interconnections ................................................................ ......................... 22

2.6 NETWORK TOPOLOGY & TRAFFIC ENGINEERING ......................................................... .............. 232.6.1 Access Microwave topology & dimensioning ......................................................... ... 242.6.2 Access MW Resilience rules .............................................................. ......................... 272.6.3 Backhaul & Core transmission network dimensioning rules ..................................... 282.6.4 Traffic engineering .................................................................................................... 29

2.7 NETWORK SYNCHRONISATION .............................................................. .................................... 352.7.1 Self Built Transmission network ................................................................................ 362.7.2 Ethernet Managed services ............................................................... ......................... 372.7.3 DWDM network ........................................................... .............................................. 382.7.4 Mobile network clock recovery ......................................................... ......................... 39

2.7.4.1 Legacy Ran nodes ........................................................................................................... 392.7.4.2 Ericsson SRAN 2G ....................................................................................................... 392.7.4.3 Ericsson SRAN 3G & LTE ........................................................................................... 392.7.4.4 NSN 3G .......................................................................................................................... 402.8 DATA COMMUNICATIONSNETWORK(DCN) .............................................................. .............. 40

2.8.1 NSN 3G RAN Control Plane routing ......................................................................... 412.8.2 NSN 3G RAN O&M routing .............................................................. ......................... 41

2.9 TRANSMISSION NETWORK PERFORMANCE MONITORING ........................................................ ... 433.0 SITE CONFIGURATION ............................................................ .............................................. 45

3.1 CORE SITES ............................................................................................................................... 453.2 BACKHAUL SITES ...................................................................................................................... 51

3.2.1 BT TT locations ........................................................... ......................................................... 563.3ACCESS LOCATIONS ...................................................................................................................... 57

3.3.1 Access sites (Portacabin installation) .......................................................... .............. 573.3.2 Access site (Outdoor cabinet installation) .............................................................. ... 60


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Figures

Figure 1 Proposed NSI transmission solution .................... ...................... ...................... ...................... ..................... . 7Figure 2 Example data centre northbound physical interconnect .................... ...................... ...................... ............... 8Figure 3 - Dublin Dark fibre IP/MPLS network ....................... ...................... ...................... ...................... ............. 10Figure 4 - National North East area IP/MPLS microwave network .................... ...................... ...................... ......... 11Figure 5aBT Total Transmission network............................................................................................................ 14Figure 5bNSI logical and physical transmission across the BT network ..................................... ...................... .. 15Figure 7Access Microwave topology ...................... ...................... ..................... ...................... ...................... ...... 21Figure 8Example VSI grouping configuration ...................... ...................... ...................... ...................... ............. 23Figure 10IP/MPLS traffic engineering .................... ...................... ...................... ..................... ...................... ...... 30Figure 11Enterprise traffic engineering ............................................................................................................... 31Figure 12Downlink traffic control mechanism ..................... ...................... ...................... ...................... ............. 32Figure 13- Normal link operation ............................................................................................................................ 34Figure 14

Self built synchronisation distribution ................... ...................... ...................... ...................... ............. 37

Figure 151588v2 distribution over Ethernet Managed service .................... ...................... ...................... ............. 38

Tables

Table 1: Self build fibre diversity ................... ...................... ...................... ...................... ......... 12Table 2: TT Access fibre diversity ..................... ..................... ...................... ...................... ...... 13Table 3 List of L3VPNs required......................................................................................... 18Table 4 Radio configuration V air interface bandwidth ..................................................... 25Table 5: Feeder link reference .................... ...................... ...................... ...................... ............. 26Table 6: CIR per technology reference...................................................................................... 26Table 5 Sample Quality of Service mapping...................................................................... 30Table 6 City Area (Max link capacity = 400Mb\s).............................................................. 33Table 7 Non City Area (Max link capacity = 200Mb\s) ..................................................... 33Table 7: Synchronisation source and distribution summary .............................................. 36Table 8: DCN network configuration per vendor................................................................. 41Table 9: NSI transmission network KPIs and reporting structure .................................... 44Table 10: Core site build guidelines ..................... ..................... ...................... ...................... ...... 51Table 11: Backhaul site build guidelines ..................... ...................... ...................... .................... 56Table 12: Access site categories ................... ...................... ...................... ...................... ............. 57Table 11: Access site consolidationNo 3PP services in place ............................. .................... 63Table 12: Outdoor cabinet consolidation existing 3PP CPE on site ............................ ............. 64


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1.0 Introduction

1.1 Background

The aim of this document is to detail the design and architecture principles to

be applied across the Netshare Ireland (NSI) transmission network. NSI, as

detailed in the transition document, is tasked with collapsing the existing

transmission networks inherited from both Vodafone Ireland and H3G Ireland

onto one single network carrying all of each operators enterprise and mobile

services. As detailed in the transition document it is NSIs responsibility to

ensure that the network is future proof, scalable and cost effective with the

capability to meet the short term requirements of network consolidation and

the long term requirements of service expansion.

1.2 Scope of document

This document will detail the proposed solutions for the access and backhaul

transmission networks and the steps required to migrate from the current

separate network configuration to one consolidated network. While the

required migration procedures are detailed within this document timescales

required to complete these works are out of scope.

1.3 Document structure

The document is structure as follows:

Section 2 describes the desired end to end solution for the consolidatednetwork and the criteria used to arrive at each design decision

Section 3 covers the site design and build rules


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2.0 Proposed Network architecture

As described in section 1.1, NSI is required to deploy and manage a

transmission network which is future proof, scalable and cost effective. As

services, particularly mobile, move to an all IP flat structure it is important to

ensure that the transmission network is evolved to meet this demand.

Traditionally transmission networks and the services that ran across them

were linked in the sense that the service connections followed the physical

media interconnections between the network nodes. For all IP networks

where any to any logical connections are required, it is essential that the

transmission network decouples the physical layer from the service layer.

For NSI Ireland the breakdown between the physical and service layer can be

described as:

Physical media layer

1. Tellabs 8600 & 8800 multiservice routers

2. Ethernet Microwave (Ceragon / Siae)

3. Dark Fibre (ESB / Eircom / e|net)

4. Vodafone DWDM (Huawei)

5. SDH (Alcatel Lucent/Ericsson)

6. POS / Ethernet (Tellabs)

7. Managed Ethernet services (e|net, UPC,ESBT, Eircom)

8. BT Total Transmission network (TT)

Service layer

o IP/MPLS (Tellabs / BT TT)

o L2 VPN (Tellabs / BT TT)

o E-Line (Ceragon / Siae)

o TDM access (Ceragon / Siae / Ericsson MiniLink)

By decoupling the physical media layer from the service layer it allows NSI the

flexibility to modify one layer without impacting the other. Therefore routing

changes throughout the network are independent of the physical layer once

established. In the same way changes in the physical layer such as new

nodes or bandwidth changes are independent of the service routing. This in


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turn ensures that transmission network changes requiring 3rd party

involvement are restricted primarily to the physical layer which, once

established, should be minimal.

While seamless MPLS from access point through to the core network is

possible, for demarcation purposes the NSI transmission network will

terminate at the core switch (BSC / RNC / SGw / MME / Enterprise gateway).

2.1 Transmission network

Figure 1 details the proposed solution for the NSI transmission network.

680-SR12-1 680-SR12-2

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/29netrworkallocated tobackendBTS interface.

Staticroutes requiredtoOMU, DCNandRNCnetworks??

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Figure 1 Proposed NSI transmission soluti on

To explain in detail the proposed transmission solution the network will be

broken into the following areas

Data centre Northbound interfaces

Self build backhaul

Managed backhaul

Backhaul routing

Access Microwave network


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Network QoS & link dimensioning

DCN

Network synchronisation

2.1 Data Centre solution

2.1.1 Physical interconnection

VFIE and H3G operate their respective networks based on a consolidated

core.

All core switching (BSCs, RNCs, EPCs, Master synchronisation, DCN,

security) for both H3G and VFIE are located in Dublin across 4 data centres.

They are;

1. CDC1 DN680 Vodafone, Clonshaugh (VFIE)

2. CDC2 DN706 BT, Citywest (VFIE)

3. CDC3 DN422 Data Electronics, Clondalkin (VFIE)

4. CDC4 DNxxx Citadel, Citywest (H3G)

Figure 2 below details the possible northbound connections @ each data

centre

Figure 2 Example data centre northbound physical in terconnect

NSI will deploy 2 x Tellabs 8800 multiservice routers (MSRs) at each of thedata centres. 2 routers are required to ensure routing resilience for the


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customer traffic. The 8800 hardware will interface directly at 10Gb\s, 1Gb\s &

STM-1 with the core switches, DCN and synchronisation networks for both

operators.

Each of the Data centres will be interconnected using n x 10Gb\s rings. RSVP

LSPs are not supported on the current release of 8800 interfaces in a Link

Aggregation Group (LAG) so multiple 10Gb\s rings can be used to transport

traffic from both operators. In the first deployment 1 x 10Gb\s ring will be

deployed which can be upgraded as required. Consideration was given to a

meshed MPLS core, however the Nx10Gb\s ring was deemed to be

technically sufficient and more cost effective. This design may be revisited in

the future based on capacity, resilience and expansion requirements.

Interfacing to the out of band DCN (mobile and transmission networks) and

synchronisation networks will be realised through 1Gb\s interfaces.

All interfaces to legacy TDM and ATM systems are achieved through the

deployment of STM-1c and STM-1 ATM interfaces.

Physical and layer 3 monitoring of the physical interfaces is active on all trunk

interfaces so in the event of a link failure all traffic is routed to the diverse path

and the required status messaging and resilience advertisements are

propagated throughout the network. These will be explained in detail in each

of the sections dealing with service provisioning.

2.2 Self build backhaul network

Self build refers to network hardware and transmission links that are within the

full control of NSI in terms of physical provisioning. The Self built Backhaul

network interconnects the aggregation sites and the core data centre

locations via a mix of Ethernet, Packed over SDH (POS) and SDH point to

point trunks. The service layer will be IP/MPLS based on the Tellabs 8600

and 8800 MSR hardware. Figures 3 and 4 are examples of the proposed

network structure,


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Dublin Dark Fibre v1.0

Core Dublin ring STM16 (future 10G/nx10G/40G); ISIS L2-only or L1-2 if between routers in same location

ISIS 49.0031

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PoC3 connections GE (future subrate_10G/line_rate_10G); ISIS L1-only

PoC3 connections GE; ISIS L1-only

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Figure 3 - Dublin Dark f ibre IP/MPLS network

In the network Dark fibre from Eircom, ESB and e|net will be used as the

physical media interconnect. Interconnections based on aggregation

requirements will be at speeds of 1Gb\s, 2.5Gb\s (legacy) or 10Gb\s. A

hierarchical ISIS structure of rings will be used to simplify the MPLS design.

The Level 2 areas will be connected directly to the core data centre sites with

level 1 access rings used to interconnect traffic from the access areas. The L2

access areas will have physically diverse fibre connections to 2 of the data

centres. Physically diverse LSPs are routed from the L2 aggregation routers

to each of the data centres facilitating diverse connectivity to each of the core

switching elements. This provides protection against a single trunk or node

failure.

The access rings will have diverse fibre connectivity to a L1/2 router which will

perform the ABR function.

Within each access ring diverse LSPs will be configured to the ABR or ABRs

providing access route resilience against a single fibre break and/or node

failure.

RSVP LSPs with no bandwidth reservations will be used to route the LSPs

across the backhaul network. All LSPs will use a common Tunnel Affinity

Template. This provides the flexibility to re-parent traffic to alternative trunks

without a traffic intervention should that be required. It is proposed to use a


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combination of strict and loose hop routing across the network. The working

path should always be associated with the strict hop with the protection

assigned to either a strict or loose hop. For those LSPs routed over the

Microwave POS trunks, strict hops will be used to ensure efficient bandwidth

management. For those routed across Dark fibre or managed Ethernet loose

hops will be used. In a mesh network where there are multiple physical

failures and multiple paths possible this approach offers a greater level of

resilience.

LH038200172.25.0.16

DN706201172.25.0.4

DN680200172.25.0.1

DNBW1200172.25.128.1

KECAP200172.25.128.2 MHFKS200

172.25.128.5

MHWD1200172.25.128.3

WHLIN200172.25.128.6

MH009200172.25.128.7

LH001200172.25.128.8

LH011200172.25.128.9

CNSGA200172.25.128.11

CNMCR200172.25.128.12

LHDDK200172.25.128.14

10/1/4

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449 10.82.128.48/30 5

0

Figure 4 - National North East area I P/MPLS microwave network

Figure 4 details a sample of the self built backhaul network routed over N+0

SDH microwave links and rings. In this situation LSPs are routed over


12/64




multiple hops to the data centres and all routers will be added to the Level 2

area. In order to ensure that traffic is correctly balanced across the SDH

trunks RSVP LSPs will be routed statically giving NSI a greater level of

control over the bandwidth utilisation. LSPs from each collector will be

associated with a particular STM-1 and routed to the destination accordingly.

Traffic aggregating at each collector is then associated with a particular LSP.

NOTE: The transition document states that the National SDH Microwave

network should be replaced by NSI with the BT TT network (See section

2.1.2) or a National DF network. However, as this will take time and

consolidated sites are required nationally in the short term, the network

described in Figure 4 will be utilised over the short to medium term.

2.3.1 Self build fibre diversity

The table below details the physical diversity requirements for fibre based on

traffic aggregation in the transmission network. Note that in some cases

where the capital cost to provide media diversity over fibre is prohibitive

Microwave Ethernet will be considered as a medium term alternative. While

the microwave link will for the most part be of a lower capacity than the

primary fibre route the degradation of service during the fibre outage may beacceptable for short periods to maximise the fibre penetration

Aggregation level Diversity Comments

< 5 Single fibre pair No diversity

5 x 9 Flat ring Two fibre pairs sharing

the same duct

> 9 Fibre duct diversity 5m fibre separation to

the aggregation router

Table 1: Self build fibre diversity

Note that the above table details the desired physical separation. In some

cases the physical separation may not be physically possible and a decision

on the aggregation level will be made based on other factors such as location,

security, landlord, antenna support structure and cost.


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2.3 Managed backhaul

Managed backhaul refers to point to point or network connections facilitated

by an OLO over which NSI will transport traffic. In this case the OLO will

provision the physical transmission interconnections.

Presently VFIE use Eircom and e|net as a managed service vendor. In this

case VFIE have individual leased lines from each of the vendors providing

point to point fixed bandwidth connections.

H3G to date have used BT as their backhaul transmission vendor where all

traffic from the access network is routed across the National BT Total

Transmission (TT) network.

2.3.1 TT Network contractThe BT TT contract allows H3G to utilise up to 70Gb\s of bandwidth across a

possible 200 collector or aggregation locations. Presently BT has configured

multiple L3VPNs across the TT to route traffic between the collector locations

and the data centre site at Citadel (Citywest).

BT deployed 2 x SR12 (ALU) routers at Citadel to terminate all of the traffic

from the possible 200 x locations.

H3G can interconnect from their access network at a BT GPOP onto a

collocated SR12 or APOP. At an APOP BT deploy an Alcatel-Lucent (ALU)

7210 node and extend the TT to this point. The physical resilience from the

GPOP to the APOP depends on the traffic to be aggregated at the site. See

Table 2.

Collector

Type

Sites

aggregated

Physical resilience Comments

Small 5 None

Medium 5 < x 9 Flat ring

Large 10 Diverse fibre duct

Table 2: TT Access fibre diversity

Figure 5a details the configuration of the BT TT solution.


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Figure 5aBT Total Transmission network

Because BT route traffic to and from the collector points over L3VPNs theymust be involved in the provisioning process for all RBS across the network.

As described in section 2.0 it is proposed to separate the physical

interconnection of sites from the service provisioning for NSI. To achieve this

across the TT NSI must use the TT to replicate physical point to point

connections across the backhaul network.

It is proposed to change the BT managed service from a Layer 3 network to a

layer 2 network and replicate the approach taken in the self built network. Theend result being that the provision of services across the NSI backhaul

network is consistent regardless of the underlying physical infrastructure (Self

built or managed).

In order to replicate the self built architecture and utilise the BT TT contract it

will be necessary to extend the TT network to a second data centre. It is

proposed to extend the BT TT to the VFIE date centre in Clonshaugh.

At Citadel and Clonshaugh the TT will interconnect with the 8800 network on

Nx10Gb\s connections. While it is not necessary to deploy 2 x SR-12 TT


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routers at the data centres due to the path resilience employed, it will be

useful in terms of load balancing and future bandwidth requirements. As with

the self build design, resilience will be achieved through the physical path

diversity to diverse data centre locations from each of the BT GPoPs.

Figure 5b illustrates the physical and logical connectivity across the BT TT.

BT

Total Transmission

Core

L1/2

BT - Alcatel7210- Collector

1Gbit/s

1Gbit/s

BT

IP GPoP

Ballymount

BT

IP GPoP

HPD 2

10Gb

BT

IP GPoP

HPD 1

10Gb

10Gb\ s NSI MPLS 10Gb\ s NSI MPLS10Gb\ s NSI MPLS

Symmetricom

TP500

ge

P1_1588v2

P1_SyncE

E-Lines on BT

TT

Citadel

100Clonshaugh

ADVA

XG210

NSI

MPLS ABR

(1)

L1/2

SymmetricomTP500

ge

P1_1588v2

P1_SyncE

NSI

MPLS ABR

(2)

ADVA

XG210

NSI MPLS

Collector

1G/10G 1G/10G 1G/10G 1G/10G

1G/10G

1Gb\s 1Gb\s

Primary &

secondary

LSPs

E-Lines from BT

Collector to

GPOP

Figure 5b

NSI logical and physical transmission across the BT network

VLAN trunks over E-Lines are configured from the collector to the GPOP over

which LSPs are configured to the ABRs using LDP. LDP will facilitate

automatic label exchange within the MPLS network and remove the

requirement for manual configuration in the access area.

In the BT TT network, VLAN trunks over E-Lines are configured for each ABR

to one of the parent data centres. RSVP-TE LSPs can be configured across

these trunks to any of the data centre facilities in a resilient manner.

Dual ABRs are used to ensure hardware resilience for the access areas

where up to 20 collector nodes could be connected to a BT GPOP in this

manner.


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2.3.3 Backhaul network selection

In some cases NSI will have the option to use either self build dark fibre or

managed services to backhaul services from a particular aggregation point. In

this case a number of factors must be considered when selecting the network

type. They are;

Factor Self Build Managed Comment

Long term

bandwidth

requirements

High Low /

medium

For large bandwidth sites

dark fibre may offer the

more attractive cost per bit

Operational Cost

impact

High/Medium Low To reduce the impact on

the operational expenditure

dark Fibre CapEx deals

may be more attractive

Surrounding

network

Dark fibre Managed The transmission network

selection should take

account of the surrounding

backhaul type. This is to

ensure that the

interconnecting clusters are

optimally routed through

the hierarchical structure.

2.4 Backhaul routing

Backhaul routing can be split into legacy (TDM/ATM) services, enterprise

services and IP services.

2.4.1 Legacy mobile services

Legacy mobile services relate to 2G BTS and 3G RBS nodes with TDM and

ATM interfaces. For these services NSI will configure pseudowires (PWEs)


17/64




across the MPLS network. ATM services will be carried in ATM PWEs with

N:1 encapsulation used for the signalling VCs to reduce the number required.

Userplane VCs can be mapped into single PWE. TDM services will be

transported using SAToP PWEs. At the core locations MSP1+1 protected

STM-1 interfaces will be deployed between the 8800 MSRs and the core

switches (BSC / RNC).

Note: Multichassis MSP feature is not available on the Tellabs 8800 MSRs.

Therefore MSP1+1 protecting ports will be on separate cards.

At the access locations MSP protection for ingress TDM traffic will be

configured in the same way on the 8600 nodes.

PWEs for legacy services will be routed between the core and collector

locations over physically diverse LSPs.

2.4.2 Enterprise services

Similar to legacy services, enterprise services will be routed between the core

and collector locations over diverse or non diverse LSPs based on the

customers SLA. For the most part enterprise services are provided as

Ethernet services. In this case Ethernet PWEs will be configured to carry the

services. A Class of Service (CoS) will be applied to the Ethernet PWE basedon the customers SLA.

At the core locations the service will be handed to the customer network over

an Ethernet connection with VLAN separation for the individual customers. In

the event that multiple customers are sharing the same physical interfaces

SVLAN separation per customer can be implemented. This will be finalised

based on a statement of requirements from the parent operator.

TDM services for enterprise customers will be treated the same as legacy

TDM services described in 2.4.1 with STM-1 interfaces used to interface the

core switches

2.4.3 IP services

2.4.3.1 L3VPN structure

For IP services L3VPNs will be configured across the MPLS network.All

routing information will be propagated throughout each L3VPN using BGP.


18/64




The IP/MPLS network will be configured in a hierarchical fashion with route

reflectors used to advertise routing within each area. Route Reflectors (RRs)

will be implemented in the core area with all level 2 routers peering to those

RRs. The ABRs between the level 1 and 2 areas will act as the route

reflectors for the connected level 1 areas. This will reduce the size and

complexity of the routing tables across the network.

For each service a L3VPN will be configured. Because H3G and VFIE use

different vendors and have different requirements in the core the number of

L3VPNs required differ slightly. Table 3 details the L3VPNs to be configured

across the NSI network.

Parent L3VPN Description Comment

VFIE 2G UP User Plane Separate L3VPNs are configured for

each BSC

VFIE SIU O&M Baseband

aggregation switch

VFIE RNC UP 3G User Plane Separate L3 VPN are configured for

each RNC

VFIE SRAN O&M SRAN O&M

VFIE Synchronisation 1588v2 network

VFIE Siae O&M Ethernet

microwave O&M

VFIE MiniLink O&M O&M for the

MiniLink PDH

network (SAU-IP)

H3G 3G UP User plane A single L3VPN for all RNCs

H3G 3G CP Control plane A single L3VPN for all RNCs

H3G 3G O&M (RNC) Operation and

maintenance

A single L3VPN for all RNCs

H3G 3G O&M RBS Operation and

maintenance

A single L3VPN for all RBS

H3G TOP 1588v2 network Synchronisation

H3G Ceragon O&M Ethernet

Microwave O&M

VFIE LTE Tbc Tbc

H3G LTE Tbc Tbc

Table 3 List of L3VPNs required


19/64




As services are added to the network they will be added as endpoints to the

respective L3VPN for that service and parent core node. This is achieved by

adding the endpoint interface and subnet to the VPN. Any adjacent network

routing required to connect to a network will be redistributed into the VPN

also.

VFIE use /30 subnets to address the mobile services across the network. This

results in a large number of endpoints within each L3VPN. For that reason the

networks will be split based on the parent core switch. This results in a L3VPN

for each of the services routed to each of the RNCs/BSCs. For the H3G

network, /26 networks are typically used at each of the endpoints. This

summarisation reduces significantly the number of endpoints required within

each VPN and consequently the number of VPNs.

Sections 3 and 4 detail the impacts the proposed design have on each of the

operators existing solutions and the steps, if any, required to migrate to the

proposed solution.

2.4.3.2 IP service Resilience

Transport resilience

Within the backhaul network IP services will be carried resiliently between the

core and collector locations over diversely routed LSPs. It is proposed to use

a combination of strict and loose hop routing across the network. The working

path should always be associated with the strict hop with the protection

assigned to the loose hop. By configuring the protection on a loose hop it will

allow the IGP to route the LSP between the source and destination. In the

event of a failure all traffic will be switched to the protecting LSP which has

been routed between the source and destination via the IGP. In a mesh

network where there are multiple physical failures and multiple paths possible

this approach offers a greater level of resilience.

Note, as described in section 2.2, in the case where both the main and

protecting paths are routed over Microwave STM-1 trunks, strict hop routing

will be employed for both paths to ensure optimum utilisation of the available

capacity.


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Router Resilience

Within the level 2 area of the network dual routers are deployed to ensure

resilience at locations aggregating large volumes of traffic. In this case

resiliently LSPs are routed from the collector nodes to both routers. In the

event of a router failure traffic will route over the operating router until such

time as the second router is operational after which the routing will return to

the initial configuration.

Core switch resilience - VRRPFor all connections to the mobile core, Virtual Router Redundancy Protocol

(VRRP) should be used. While the VRRP implementation will differ slightly

based on the mobile core vendor and function, the objective is to ensure that

the transmission network to the core has full interface and router redundancy.

10Gb\s (with LAG if required) cross links at each data centre location between

the 8800 nodes will be implemented to support the router redundancy.

For the 8800 nodes during restart it is possible that the router will advertise

the interface addresses to the core switch (BSC/RNC/SGw/MME) before the

router forwarding function is re-established. This may result in the temporary

Black Holing of traffic. To avoid this scenario a separate connection is

required between the routers with a default route added to each for all traffic.

This will avoid the above scenario. It is proposed that a 10Gb\s link should be

used for this also.

2.5 Access Microwave network

The target access microwave network with be based on an Ethernet

microwave solution utilising ACM to maximise the available bandwidth. In the

existing networks H3G use Ceragon IPx Microwave products while VFIE use

the Siae Alc+2 and Alc+2e products. While it is envisaged that NSI will tender

for one supplier it is not planned to replace one of the existing networks. The

access network solution must be designed so as to ensure both vendors


21/64




products and the services transported across them inter operate without

issue.

Figure 7 details a possible configuration of the access network topology

utilising both vendors products.

Cgn

Cgn

Siae

Siae

Siae

CgnGigE

GigE

GigE

GigE

elp

Cgn

Cgn

Cgn

Siae

Siae

Siae

Siae

Siae

CgnCgn

Siae

Siae Siae

GigE

Cgn

Cgn

Aggregation Node 86xx

Figure 7Access M icrowave topology

2.5.1 Baseband switching

For the access network all traffic will be routed at layer 2 utilising VLAN

switching at each point. VLANs will be statically configured at each site on

each of the indoor units. For VFIE, unique VLANs are used to switch traffic

from each of the RBS nodes. For H3G, common VLANs are used for each of

the service types switched across the network. They are;

UP VID = 3170

CP VID = 3180

O&M VID = 3190

TOP VID = 3200

Ceragon O&M = 3210

Note: Future developments may result in the deployment of all outdoor MW

Radio products in the traditional MW Bands and in the E-Band. In this case at

feeder locations a cell site router may be deployed to perform the baseband

switching function using IP/MPLS routing functions. Should this solution be


22/64




employed in the future, an additional design scenario will be described and

added to this document.

2.5.2 Microwave DCN

All Microwave DCN will be carried in band (this is already the case for the

Ceragon network elements). As sites are consolidated and migrated to the

consolidated network, it will be necessary to migrate the Siae DCN solution to

an in band solution. It is proposed to assign VLAN ID 3000 to the Siae

network for DCN.

2.5.3 Backhaul Interconnections

The access network will interface with the backhaul network over multiple GE

interfaces. The interfaces can be protected or not depending on the capacity

requirements. While LAG is possible on the GE interfaces the preference will

be to use ELP on the access router with interconnected IDU interfaces in an

active / active mode.

In a situation where greater than one 1Gb\s is required over the Radio link,

LAG can be used. The limitation on the access interfaces is that the interfaces

in a LAG on the Tellabs 8600 must be on the same interface module. This is aplanned feature for release FP4.1 and is planned to be deployed in the NSI

network forQ2 2014.

VSI interfaces will be used to associate common network VLANs arriving on

separate physical interfaces to a common virtual interface. This ensures that

the approach used to assign a single subnet per traffic type per cluster can be

continued where required. A separate VSI interface will be configured for each

service type and added as the endpoint to the required IPVPN. Any static

routes required to connect to and from the DCN network will use the VSI

interface address. Figure 8 details the operation of the VSI interface.


23/64




GE

GE

GE

VSIVSI

VSI

GE

GE

GE

Cgn

Cgn

Siae

VID3170

VID3210VID3000

VID3000

VID3210VID3170

VID3000VID3210

VID3170

VID3000

VID3210VID3170

VID3000

VID3210VID3170

VID3000

VID3210VID3170

VID3000 Siae DCN

VID3210 Ceragon DCNVID3170 H3G UP

VID3000

Siae DCN


VID3000 Siae DCN


Tellabs 86xx

Figure 8Example VSI grouping conf iguration

2.6 Network topology & traffic engineering

The NSI transition document details the targets for network topology, traffic

engineering and bandwidth allocation on a per site basis for each of the

mobile networks. In summary they are;

No more than 1 Microwave hop to fibre (Facilitated by providing fibre

solutions to 190 towns)

No contention for shared transmission resources (NSI are required to

monitor utilisation and ensure upgrade prior to congestion on the

transmission network)

Traffic engineering (CoS, DSCP, PHB) will be assigned equally to each

service type from each operator. At a minimum the following will be

applied;

o Voice (GBR)

o Video/interactive (VBR-RT)

o Enterprise (VBR-NRT)

o Data (BE)

Bandwidth allocation per site

o Dublin & other cities (400Mb\s\site)

o Towns (5 10K) (300Mb\s\site)


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o Rural (200Mb\s\site)

This chapter will explain in detail the required Access, Backhaul and Core

transmission network dimensioning guidelines and traffic engineering rules to

achieve the targets set out in the transition document

2.6.1 Access Microwave topology & dimensioning

The national access microwave network will be broken into clusters of

microwave links connected, over one or multiple hops, to a fibre access point.

The fibre access point can be part of the self built or managed backhaul

networks but must have the following characteristics;

Long term lease or wholly owned by NSI or one of the parent operators

24 x 7 access for field maintenance

Excellent Line of Site properties

Facility to house a significant number of microwave antennas

Space to house all the required transmission nodes and DC rectifier

systems

No Health and safety restrictions

Before creating a cluster plan, each site in the MW network must be classified

under the following criteria;

Equipment support capabilities

Line of sight capabilities proximity to existing fibre solution

Existing frequency designations

Site development opportunities

Landlord agreements (Number and type of equipment/services

permitted under the existing agreements)

Term of agreement

Creating a database as above will allow the MW network planning team to

create cluster solutions where a number of sites are associated with a

designated head of cluster. As per the transition document the target topology

is one hop to a fire access point. However this will not always be possible due

to one or a combination of the following factors;


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Line of Site

Channel restrictions

Proximity of fibre solutions

Once the topology of the cluster is defined it is necessary to define thecapacity of each link within the cluster. For tail links this is straight forward, the

link must meet the capacity requirements of the transition document;

Dublin & other cities (400Mb\s\site)

Towns (5 10K) (300Mb\s\site)

Rural (200Mb\s\site)

For feeder links, statistical gain must be factored while still meeting the

capacity requirements for each of the individual sites. Table 4 gives examplesof existing MW Radio configurations and the average air interface speeds

available.

Channel

Bandwidth

Configuration Max Air interface speed @

256QAM

14MHz Single channel 85Mb\s

28MHz Single channel 170Mb\s

28Mhz 2 channel LAG 340Mb\s

28MHz 3 channel LAG 500Mb\s


56Mhz Single Channel 340Mb\s


56MHz 3 channel LAG 1.02Gb\s

56MHz 4 channel LAG 1.34Gb\s

E-Band 1GHz 1Gb\s

Table 4 Radio configuration V air interface bandwidth

Table 5 provides a guide for feeder link configurations based on the number

of physical sites aggregated across that link.

Physical sites

aggregatedCity Urban Rural Comments

2P1: E-band

P2: 2 x56MHzP1: 1 x56MHz P1: 1 x56MHz 3:1 Stat gain


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3P1: E-band


4P1: E-band


5 P1: E-band


6P1: E-band


7P1: E-band

P2: 3 x56MHz

P1: E-band

P2: 3 x56MHzP1: 2 x56MHz 3:1 Stat gain

8P1: E-band

P2: 4 x56MHz

P1: E-band

P2: 3 x56MHzP1: 2 x56MHz 3:1 Stat gain

Table 5: Feeder link reference

Note that no more than 8 physical sites should be aggregated on any one

feeder link.

For MW links utilising adaptive code modulation (ACM) it is important that at

the reference modulation (i.e. the modulation scheme for which ComReg have

allocated the Max EIRP) is dimensioned so as to meet the sum of the CIRs

from each operator across that link.The total CIR per link is based on the product of the RAN technologies

deployed and the CIR per RAN technology.

Service RAN technology CIR (Mb\s)

Voice 2G 1

Voice 3G 1

Voice LTE 1

Data GPRS 1.5Data R99 2

Data HSxPA 15

Data LTE 20

Table 6: CIR per technology reference


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Should restrictions apply in terms of hardware, licensing, topology with the

effect that links cannot be dimensioned as per table 4 then the following

formula should be used to determine the minimum link bandwidth.

Min Feeder l ink c apacity = MAX (VFIE CIR + H3G CIR, Max Tai l l ink capacity)

CIR = Total CIR across all links aggregated from each operator

Max Tail link capacity = Max tail link capacity of all sites aggregated

across the feeder link

The formula is designed to facilitate the required capacity for each site based

on location while at the same time ensuring, where multiple sites are

aggregated, that the minimum CIR is available to each site.

2.6.2 Access MW Resilience rules

The resilience rules for the access MW network are based on the number of

cell sites and enterprise services aggregated across the link. 1+1 HSB will be

used to protect the physical path.

Collector site Sites

aggregated

Physical resilience Comments

Small 5 None

Medium /

Large

> 5 1+1 HSB

Note that while LAG can be considered as a protection mechanism, allowing

the link to operate at a lower bandwidth in the event of a Radio failure, NSI will

protect the Radios in a LAG group using 1+1HSB to ensure the highest

hardware availability for a physical link. NSI will consider LAG for capacity

only and 1+1 HSB for protection.

The target microwave topology, as described in the transition document, is for

1 microwave hop to fibre which will result in minimal use of 1+1 HSB

configurations. However in the event that this topology is not possible NSI will

implement protection as described above.


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2.6.3 Backhaul & Core transmission network dimensioning rules

Forecasting data utilisation across mobile networks is unpredictable due to

the fact that service is quite new and technologies are still evolving. The

dimensioning rules for the core and backhaul networks will be based in the

first instance on projected statistical gain.

To ensure that the Backhaul and Core networks are dimensioned correctly for

the initial network consolidation the following criteria will be used;

Network Statistical gain Action

Backhaul network Less than 6 ok

Greater than 6 and less than 8 under review

8 or greater upgrade

Core Dark Fibre Less than 8 ok

Greater than 8 and less than 10 under review

8 or greater upgrade

The statistical gain will be based on the average throughputs per technology

aggregated. The statistical gain is based on the following calculation;

Stat Gain = Total existing service capacity + Forecasted service capacity

Backhaul capacity

For the backhaul and core networks the current utilisation will be monitored on

a monthly basis with the forecasted Statistical gain forecasted over an annual

basis. This will give rise to programmed capacity upgrades across the

Backhaul (managed and self build) and Core networks. The time to upgrade

trunks across these networks is typically between 6 and 24 months depending

on the upgrade involved.

To facilitate this process the parent companies must provide 12, 24 and 36

month rolling forecasts at least twice yearly. These forecasts must detail at a

minimum;

Volume deployment per service type per geographic area

Average throughput per service type

Max allowable latency per service type


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NSI will constantly monitor utilisation Vs forecast and feedback to the parent

companies. This will ensure that the capacity forecasting processes are

optimised over time.

2.6.4 Traffic engineering

As described in section 2.6.2, while all efforts will be made to ensure

congestion and contention is minimised across the transmission network, in

some cases it will be unavoidable. NSI must ensure, in such circumstances,

that both operators have equal access to the available bandwidth. To ensure

that this is the case traffic engineering must be employed across the

transmission and RAN networks;

QoS mapping

Shaping

Policing

Queue management

Quality of service is used to assign priority to certain services above others.

Critical service signalling and GBR services will be assigned the highest

priorities with VBR services assigned lower priority based on the service

and/or the technology. There are large variations in the bandwidth

requirements for LTE, HSPA, R99 and GPRS. For this reason, if all services

were assigned equal priority, during periods of congestion, the low bandwidth

services would be disproportionally impacted to such an extent that they may

become unusable. For that reason, the low bandwidth data services will be

assigned a higher priority to those presenting very high bandwidths.

QoS along with the queue management function should be designed to

ensure, during periods of congestion, that equivalent services from the two

operators have equal access to the available bandwidth.

Table 5 details the proposed QoS mapping for all mobile RAN services.

Traffic Type DSCP L2-pbit MPLS Queue

Signalling, synchronisation, routing

protocols,

24,40,48,49,56 7 CS7 (Strict)

Speech 46 6 EF (Strict)


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VBR Streaming, GPRS data,

Gaming

32,34,36,38 4 AF4 (WRED)

R99 data 24,26,28,30 3 AF3 (WRED)

HS Data 18,20,22 2 AF2 (WRED)Premium Internet access 10 1 AF1 (WRED)

LTE Data 0,8 0 BE

Table 5 Quality of Service mapping

Traffic engineering across the IP/MPLS network

Classification

EF

Tail drop

RT

Tail drop

pG

WRED

BE

WRED

Shaper

CIR / PIR

Strict

priority

WFQ

Ingress from Core Traffic

ClassificationQueue &

Queue ManagementShaping Scheduling Trunk Interface

IP/MPLS traffic Engineering

IP Flow

IP Flow

IP Flow

IP Flow

Ingress - POC 1 Location IP/MPLS PHB

G+E

WRED

Shaper

CIR / PIR

Shaping

Figure 10I P/MPLS traff ic engineeri ng

Figure 10 describes the flow of traffic through the IP/MPLS network. On

ingress from the core and access networks traffic is classified according to the

DSCP value and mapped to the required Per Hop Behaviour (PHB) service

class. From there it is passed to the egress interface where it is queued and

scheduled based on a strict plus weighted fair queue (WFQ) mechanism.

GBR services are passed to the strict queue and VBR services are passed to

a weighted fair queue where access to the egress interface is controlledbased on the service class priority. In times of no congestion all traffic is


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passed without delay. In a congested environment, GBR services are passed

directly to the egress interface and the VBR services are queued with access

to the egress interface controlled by the weighted fair algorithm. Weighted

Random Early Discard (WRED) is used to ensure efficient queue

management. Packets from data flows are discarded at a pre-determined rate

as the queue fills up. By doing this the 3G flow control and TCP/IP flow control

should slow down resulting in reduced retransmissions and more efficient use

of the available bandwidth.

For enterprise services, policing on ingress will be implemented to ensure the

enterprise customer is within the SLA. In such circumstances a CIR and PIR

can be allocated to the customer services with a CBS and PBS assigned also.

In this case the two rate three colour marking (trTCM) mechanism will be used

to control the flow of enterprise traffic through the network.

Figure 11Enterpri se traff ic engineering

Traffic within contract and within the PBS will be marked Green, traffic greater

than the CIR and within the PIR including the PBS will be marked Yellow, all

other traffic will be marked Red and discarded. In congestion scenarios the

WRED queue management function will discard the Yellow marked packets

first.

Traffic engineering across the Layer 2 Microwave network

Input data burst Policing marking Output traffic

Data

Input data burst Policing marking Output trafficInput data burst Policing marking Output traffic

DataData

Discarded

traffic

Discarded

traffic

Yellow marked traffic.

First to be discarded in

case of network congestions

Yellow marked traffic.

First to be discarded in

case of network congestions

Policing implementation according to standard Two Rate Three Color Marker (trTCM)

CBS allows to tolerate bursts above CIR

short bursts will be marked GREEN

PBS allows to tolerate bursts above PIR

short bursts will not be discarded

Policing implementation according to standard Two Rate Three Color Marker (trTCM)

CBS allows to tolerate bursts above CIR

short bursts will be marked GREEN

PBS allows to tolerate bursts above PIR

short bursts will not be discarded


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Across the microwave network a combination of Shaping, CoS based policing,

trTCM and WRED queue management should be used to ensure congestion

control and fairness in terms of bandwidth contention.

For downlink traffic, the physical interface from the IP/MPLS network must be

shaped to the maximum bandwidth of the radio interface. This is to ensure

that egress buffer overflow is not experienced, in particular for large bursts of

LTE traffic. For LTE traffic, shaping per VLAN should also be implemented to

ensure that tail links, which may be connected to feeder links and be of lower

capacity, do not experience buffer overflow.

Note: VLAN shaping for LTE must be considered when considering the Layer

2 VLAN structure and Layer 3 addressing to the H3G LTE network.

Figure 12Downlink tr aff ic control mechanism

For uplink traffic, shaping should be applied on both the H3G and VFI RAN

nodes. This is to ensure that both operators present the same bandwidth to

the Transmission network for sharing.

Data traffic should be policed on ingress to the access microwave network on

a per service level. This ensures that during congestion, out of policy traffic

from each operator is discarded first during periods of congestion.

GE

BEP1.0

LTE

3G

2GBEP2.0

BEP2.0

H3G

VFIE

LTE traffic shaping per service

& per port (VLAN group) shaping

In order to avoid BEP2.0 buffer overflow

Sh

ap

ing

Sh

ap

ing

GE

BEP1.0

LTE

3G

2G

LTE

3G

2GBEP2.0

BEP2.0

H3G

VFIE







Sh

ap

ing

Sh

ap

ing

Sh

ap

ing

Sh

ap

ing


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As detailed in previous sections the target bandwidth for RBS sites is 400Mb\s

in the City areas, 300Mb\s in towns and 200Mb\s for all others. Tables 6 and 7

detail the proposed policing settings for the two areas.

Data traffic CIR

(Per operator)

PIR

(Per Operator)

Comments

GBR Services NA NA No Policing - Green

GPRS Data 1Mb\s Not set PIR will not be greater than

max link capacity.

Out of policy = yellow

R99 Data 2Mb\s Not set PIR will not be greater than

max link capacity.


HSDPA 15Mb\s Not Set PIR will not be greater than

max link capacity.


LTE 20Mb\s 400Mb\s Contracted SLA to operator.

Out of policy = Red

Table 6 City Area (Max link capacity = 400Mb\s)

Traffic CIR

(Per operator)

PIR

(Per Operator)

Comments

GBR Services NA NA No Policing - Green

GPRS Data 1Mb\s Not set

PIR will not be greater than

max link capacity.


R99 Data 2Mb\s Not set


max link capacity.Out of policy = yellow

HSDPA 15Mb\s Not Set


max link capacity.


LTE 20Mb\s 200Mb\sContracted SLA to operator.

Out of policy = Red

Table 7 Non City Area (Max link capacity = 200Mb\s)


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All packets within CIR and the CBS will be marked green. For 3G and HS

services the PIR should not exceed the available link capacity so packets will

be marked as yellow. For LTE traffic, out of policy traffic will be marked red

and discarded.

In some cases the sum of both operators PIR will be greater than the

available link capacity, even at maximum modulation. In this case, it will be

possible for both operators to peak to the maximum available capacity, but not

at the same time.

Figure 13- Normal li nk operation

Figure 13 details the operation of both policing and queue management on a

microwave link. For operator 1, when the traffic presented exceeds the PIR, it

is marked Red and discarded. Where the sum of both operators traffic does

not exceed the interface PIR but exceeds the available link capacity the

WRED mechanism in the outbound queue will start discarding yellow marked

packets at a predetermined rate based on the queue size. In this instance, the

3G flow control and TCP/IP (LTE) flow control mechanisms will slow down the

Policing will color

packets according

to trTCM

CIR1

Operator 1

Operator 2

PIR1

PIR2

CIR2

TX link

capacity

Discarded traffic by policing

Op1 + Op2 traffic exceeding TX link capacity. When queues start to fill-up

WRED (QoS) mechanism will start dropping YELLOW marked packets from data traffic

3G flow control & TCP/IP LTE sessions will slow down traffic of both Operators

Thus preserving GREEN packets (CIR) for both operators

Policing will color

packets according

to trTCM

Policing will color

packets according

to trTCM

CIR1

Operator 1

Operator 2

PIR1

PIR2

CIR2

TX link

capacity

Discarded traffic by policingDiscarded traffic by policing









transmission network design and architecture guidelines version 1 3

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