msan access & interconnection consult21 industry working group 10 jan 2005
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MSAN access & interconnection Consult21 Industry Working Group 10 Jan 2005. AIMS AND AGENDA. Positioning of this Industry Working Group and of this specific meeting Architecture presentation and discussion (BT) in response to industry input Industry presentation(s) and discussion - PowerPoint PPT PresentationTRANSCRIPT
MSAN access & interconnectionConsult21 Industry Working Group
10 Jan 2005
AIMS AND AGENDA
• Positioning of this Industry Working Group and of this specific meeting
• Architecture presentation and discussion (BT)
inresponsetoindustryinput
• Industry presentation(s) and discussion
• Summary and next steps
SCOPE OF MEETING• To explore platform implications of ‘MSAN
interconnect’ to inform scheduled product working group discussions
• To reach a shared understanding of:
possiblearchitectures
platformimplications
relativecostimpactonproducts
• Consultation in parallel with Ofcom consultation
• BT believes this to be a product cost management rather than an engineering problem
CONSULT21 FEEDBACK
• Views of infrastructure players:
don’twishtoberestrictedbyBT’sdesignorpreferences
foranysite,wantpricesforMSANaccessorinterconnectproductsforallservices(broadband,PPCs,PSTNvoice)
wheretheyhavetheirownbackhaul,theywanttouseitforallservices(LLU,broadband,PPCs,PSTNvoice)
‘Equivalenceofinput’regulatoryprinciple
• Scenarios drawn up with infrastructure players
• BT to provide cost implications of scenarios to give a feel for viability
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
Servicecontrol
Servicecontrol
Interconnect
ContentContentprovider-accesstoenduser
BRASISP-accesstoenduser
ExampleofdialIP
PSTNprovider-accesstoenduser
Enduser
Switch Switch
Router
Router
What is Interconnect? What is Access?• ‘Interconnect’ is between peer-level service control and
switching / routing functions
thecontrolprotocolneedstobedefined(eg,ISUP,SIP-I)
• ‘Access’ is the media and control protocol paths between the end user and the service PoP
MSAN
OCP BT
Subtendedaggregatorsite
Aggregatorsite
Metrosite
SoftSwitch
L2 Aggregator access
L3 Aggregator access
Physical media access (LLU)
L3 Metro interconnect
DSLAM
ToCoreSoftSwitch
BRASL3 Metro RouterRouter
Router
Switch
HDF
Remote MSAN
MainDistributionFrame
Enduser Enduser
ACCESS & INTERCONNECT PLATFORM SCENARIOS
Copper shelf
L2 Aggregator
L3 Aggregation Router
L2 switchSwitchL2 Metro access
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
SOFT LLU - OFCOM DIAGRAM
Fibreaccess
BTnetwork
AltnetnetworkAggregationdevice
MSAN
MSAN
MSAN
Copperloops
Copperloops
Copperloops
Altnettunnel
BTtunnel
Logical Schematic of Proposed Soft LLU from OFCOM
INTERCONNECT REALITIES
• What are the realities of today’s interconnect?
Regulatorydriveforinfrastructurecompetitionandbuild-out
LLUprovidesultimateopportunityforinfrastructurecompetitionforcurrentandnext-generationnetworkapplications
OCPstypicallyapplyalogicalprocesstomake‘buildversusbuy’decisionsinnetworkexpansion
RELATIVE COSTINGS
• No access
• Broadband / data-only access
• Broadband / data and PSTN voice access
• Relative cost cf with overall network
Basecase
CostofadditionalportsforOCPconnect+cost
ofL2switching
As(2)+L3routing+MGWatMSAN
COSTING SCENARIOS• Need to recognise that all sites are not equal…
• Scenarios addressed:
MSANisoneoftop100(Metrolocation)
• NBNocommercialadvantageifco-located!
MSANisinrange100-2000(LikelyLLUsite)
• Themostcriticaltounderstand
MSANisinrange2000+(unlikelyLLUsite)
• Costslikelytobedisproportionatelylarger
• Build as incremental cost on a nominal “base case”
potentiallyverylowforL2access
HigherforL3access(Router,MGW,etc)
• For each scenario – assume a realistic number of customer lines, and OCP interconnects (5 OCPs at each MSAN ?)
MSAN
ToBT
CopperShelf
CopperShelf
FibreShelf
LOGICAL FUNCTIONS INSIDE MSAN - NO ACCESS
• Copper Shelf & Fibre Shelf – Currently proposed MSAN components
• No OCP connection direct to MSAN, no additional gateways
• OCP connection at Metro node – with “connectivity” provided by MSAN if needed
• Relative cost of providing this = 1 unit
• Costing scenarios:
MSANisoneoftop100
MSANisinrange100-2000
MSANisinrange2000+
Indicatesadditionalcomponentrequired(overandabovecurrent21CNArchitecture)
MSAN
ToOCP
ToBT
CopperShelf
CopperShelf
FibreShelf
L2 switch
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
LOGICAL FUNCTIONS INSIDE MSAN - BROADBAND / DATA-ONLY ACCESS
• Layer 2 switch - at MSAN sites that would otherwise only offer basic SDH functionality – this could be a separate device or fully functional fibre box
• L2 OCP connection at MSAN
• L2 turnaround within MSAN infrastructure
• Relative cost of providing this = 1+x units
• Costing scenarios:
MSANisoneoftop100
• Noadditionalfunctionalityrequired-apartfromadditionalports.
MSANisinrange100-2000
• Noadditionalfunctionalityrequired-apartfromadditionalports.
MSANisinrange2000+
• WillrequireL2switchingcapability–requiresadditionalfullyfunctionalFibreboxatsomelocations.
MSAN
ToOCP
ToBT
CopperShelf
CopperShelf
MediaServer
Router
FibreShelf IP
BGW
Indicatesadditionalcomponentrequired(overandabovecurrent21CNArchitecture)
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
LOGICAL FUNCTIONS INSIDE MSAN - PSTN VOICE ACCESS
• Router – capable of handling ALL voice traffic at an MSAN, call by call routing required
• IP BGW – Border Gateway. Provided as one per OCP. Shown connected via Fibre Shelf, but could be a direct GE connection to an OCP
• Media Server – provides announcement capabilities – including 3 party call with one BT & one OCP parties (Otherwise, traffic would need to be backhauled to Metro node for these services – which defeats the lowest backhaul cost argument). BT is also required to provide a specific announcement when OCP connections are busy, indicating that the call is unable to be connected due to congestion on the BT network.
Ethernetinterfaceaggregatingallvoicetraffic.
Connectedtofibreboxduetoportandfunctionalitylimitationswithincopperelement.
COSTING SCENARIO - PSTN VOICE ACCESS • L2 OCP connection at MSAN
• L2 turnaround within MSAN infrastructure
• No requirement to support local call control under MSAN isolation
• NB: L2 switching component removed for clarity – still required for Data and Broadband access
• Relative cost of providing this = 1+x+y units
• Costing scenarios:
MSANisoneoftop100
• CapabilityshouldalreadybeavailableatMetronodeienoadditionalcost(?)
MSANisinrange100-2000
• WillrequirecapabilityhighlightedinorangeplusfibreMSANports
MSANisinrange2000+
• WillrequirecapabilityhighlightedinorangeplusfibreMSANcapabilityatsomelocationsplusports
MSAN
ToOCP
ToBT
CopperShelf
CopperShelf
MediaServer
Router
FibreShelf IP
BGW
Indicatesadditionalcomponentrequired(overandabovecurrent21CNArchitecture)
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
RELATIVE COSTS FOR PSTN VOICE ACCESS• The following is capex only
coverscostsofrouterandsessionbordercontrolwithredundancy
excludesmediaserverandOCPfibreports
basedonindicationsfromvendors-subjecttochange
• Does not include opex costs
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5000 10000 15000 20000 25000 30000 35000 40000 45000 50000
Number of lines per MSAN site
Rat
io o
f M
SA
N c
apex
wit
h P
ST
N
voic
e ac
cess
to
no
acc
ess
CONCLUSION
• MSAN interconnect is technically possible, commercial issues dominate
• Broadband / data-only access needs no additional functionality for the top 2000 MSAN sites, apart from additional fibre ports
• PSTN voice access needs significant additional functionality, adding over 50% to the capital costs of MSANs for 30000-line sites
Fordiscussionpurposesonly.Noimplementationassuranceimpliedorintended