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MPLS Deployment
Examining the Network Evolution
Agenda

Overview of the existing network infrastructure.
Potential MPLS Networks
 Current Design Practices and Market Forces
 Requirements Met by Current Designs
 Constraints of Current Design


Requirements of MPLS for the New Public Network.
MPLS Technology Evolution
 Obstacles to Deployment
 Benefits of the New Network


The Migration Process.
The Current Layered Model
 Moving to an End-to-end MPLS Network


The New Services Enabled by an MPLS Infrastructure.
Advantages of MPLS Networking
 New Services Enabled By MPLS
 Hybrid Switches Created by MPLS
 Conclusions

Overview of the Existing
Network Design
Potential MPLS Networks
Current Design Practices and Market Forces
Requirements Met by Current Designs
Product Functionality by Product
Constraints of Current Design
Potential MPLS Networks
Target Networks:
IP Service Providers of all types, not just ISPs.
 ISP backbone to start (IP centric).
 CLEC, ILEC – transport providers take on IP knowledge.
Challenges Facing IP Service Providers.
Exponential Internet growth (BW, IP prefixes).
Need to offer multiple service levels.
Need to offer new IP services.
 Ex.: Virtual Private Networks.
Current Design: The Layered Model
Content
Pop
Access Router
Switch
Access Router
Switch
Switch
Access
Core Router
Tier 1
Major Carriers
Access Router
Switch
Switch
Content
Access Router
Core Router
Access Router
Access
Access Router
Current Practice and Market Forces
Today: Layered Model.
ATM backbone surrounded by big “Core” IP routers.
IP over ATM.
Market Forces:
IP becomes universal service interface.
 VPNs, Voice, data (Internet, intranet, extranet), IP multicast.
Traditional router vendors trying to push inward to displace
ATM backbone.
Optical Internetworking poised to grab the very core of the
network hierarchy.
Requirements Met by Current Designs

ATM switching has an enormous presence in the backbone of many service
providers:


Value-add lock-ins, enabled by connection oriented link layer:






Multiple tiers
 Bandwidth
 Capacity
Congestion Aware Routing
Traffic Engineering
QoS
Traffic Management
Circuit (service) Provisioning at ATM Layer
These have been developed in the ATM control plane Extensions:
UNI
 PNNI
 ABR/CBR/VBR/UBR/GFR

Different Products Perform Critical Functions
POP
 IP Routers:
 Classify Traffic
 Forward IP
POP
CR
CR
POP
CR
CR
POP
POP
CR
CR
POP
 ATM Switches
 Provide Raw Switching Capacity
 Provides connection-oriented link
layer, that enables:
 Traffic Engineering
CR
 Hard QoS
POP
 Traffic management
 Constraint-Based / Congestion-
AR
AR
AR
AR
AR
aware routing
Constraints of Existing Designs
 COLL benefits
end at router boundary.
 SPs dislike multiple control plane protocols:

ATM and IP
 Previously Required Because IP Lacked a COLL.
 No TE, TM, CR or QoS
 Induces ‘Cost’
 Infrastructure Cost
 Operational Cost
 Management Cost
 Perceived
Complexity of ATM.
 The benefits of ATM come at the expense of the “cell tax”.


Cells make sense in many portions of the network
Cells will move to edge at OC-3 and down
 DSL, ATM IADs
 MPLS will still provide control plane
Requirements of MPLS for
the New Public Network
Connection Oriented Networking
Comparisons of COLLs
The Evolution of IP Products
Software and Protocol Requirements
Hardware Requirements
Network Management Requirements
The Requirement: Connections

Marketing Debates
Not IP vs. ATM
 Not MPLS vs. ATM


Technical Reality: Connection-oriented vs. connectionless
ATM
 IP enabled by MPLS



Connection oriented traffic allows for traffic engineering and bandwidth guarantees
(QoS) - and is already provided today in technologies like ATM and Frame Relay.
IP alone is a connectionless protocol. Its forwarding decision are made on a hop by hop
basis.


The pinned-up connection is relatively permanent, thereby allowing for resources to be
reserved and allocated.


MPLS enables to COLL behavior.
Traffic Engineering, QoS and Congestion Aware Routing
Service Providers with an existing COLL will require MPLS to be a functional
replacement.
MPLS and ATM as COLLs
 The charts below reflect that MPLS is providing the key components of a COLL
technology.
Connection ID
Connection Method
Explicit Routing
Path Setup
ATM
MPLS
VP / VC (2)
Virtual
Circuits
Designated
Transit List
UNI
Signaling
Stacked Labels (many)
Label Switched Paths (LSPs)
Explicit Route Objects
CR-LDP or RSVP-TE
To meet QoS requirements, even non-ATM LSRs should provide capabilities
similar to ATM switches:
ATM
MPLS
Queuing
Traffic
Scheduling
QoS Routing
Per-VC queuing Per-LSP queuing
Weighted per-VC Weighted per-LSP scheduling
scheduling
PNNI routing
Enhanced IGP (OSPF and IS-IS)
Product Software and Protocol Requirements
 Routing
 Not the ones you have today.
 Need TE and QoS Extensions:
 Maximum Link Bandwidth
 Maximum Allocation Multiplier (a percentage can be used for oversubscription)
 Current Bandwidth Reservation
 Resource class (color, administrative group)
 Packet loss ratio
 Link Propagation Delay
 And several others
 Signaling
 Not just LDP or RSVP
 Need CR-LDP or RSVP-TE
 With matching properties to above items.
 Both will survive !
Additional Required Connection Features
 Combined, they enable the following functions:
 Crankback
 Make-before-break
 Prioritized reroutes
 Prioritized call setup
 Bulldozer bits
 Path computation algorithms
 MPLS based recovery (recent draft submitted)
 Sophisticated path computation methods
 CAC
 Key Measurements:
Calls per second; circuit rerouting; protocol
convergence, in the presence of CR CA information.
Product Hardware Requirements
 Classification
and forwarding
 On a per connection basis







Queue
Schedule
Buffer
Shape
Policing
Marking
Throttling
 New methods
 Class Based Queuing (CBQ)
 Random Early Discard (RED/wRED)
 Not per box or per port, but per connection.
MPLS: The Common Ground

ATM Switches


Traditional Routing


Connection oriented Networking
Connectionless Packet
Routing
Connection
Switching
IP Routing and forwarding
MPLS

Connections for IP
MPLS
IP
ATM already has the right experience with the necessary algorithms.
Connection
types: Is your MPLS vendor delivering 1994 technology?
ATM
Network Management Requirements
 Management
is critical component to the migration.
 Provisioning, billing and accounting is a major operational issue.
 Sophisticated
tools already exist for current networking technologies.
 Relatively long evolution to meet SP needs.
 Many SPs have extended these even further through own engineering.
 These networks can’t migrate and restart the clock, and wait for new
tools.

They must be available day-1
The Migration Process
The Current Layered Model
Moving to an End-to-end MPLS Network
The Migration Process
Easy migration
 IP/ATM/cells
ATM
Cells
Today
 IP/ATM/FNNI
HW
 IP/MPLS/FNNI
SW
 IP/MPLS/POS
SW
F-NNI
Technology
Encapsulation and MTU
ATM
Cells
Routing Protocol
 Each step is a fully functional network.
ATM
AAL5
Header
 What is not shown
F-NNI
AAL5
Header
Dynamic MTU up to 16k
P-NNI
POS
PPP
Header
Dynamic MTU up to 16k
OSPF, RIP,
is that you
lose your COLL….which is why
you need to add MPLS back on
top.
Fixed 53 byte MTU
P-NNI
IS-IS, BGP
The New Services Enabled
by an MPLS Infrastructure
Advantages of MPLS Networking
New Services Enabled By MPLS
Hybrid Switches Created by MPLS
Conclusions
Advantages of MPLS network
 Transport technology
independent
 End to end connections
 COLL in single control plane
POP




TE
TM
QoS
CR
 Greater tunnel
hierarchy
 N2 adjacencies gone
 Minimizes IP lookup process


Intelligence at edge
Core can be simpler switches
POP
POP
CR
CR
CR
CR
POP
POP
CR
CR
CR
POP
AR
AR
AR
AR
AR
POP
Service Offerings Enabled By MPLS
 IP Routing/Forwarding on ALL ports.
 Filtering, policies, firewalling
 Customer prem. gear
 MPLS based VPNs (IP VPNs)
 Virtual leased line
 MPLS based QoS
 Service level agreements
 Voice over IP/MPLS Architectures
 IP Multicast
A New Breed of Switching Product


Hybrids that offer Ships In the Night mode (MPLS and ATM)
Many carriers today have multiple networks
Frame, IP, ATM
 Replicated operational costs


SIN – expose multiple service interfaces to customer over a single infrastructure


Only ATM switches can operate in SIN mode



VC, VP, POS, MPLS, Frame Relay…
Packet-based routers can not
Packet based IP centric services only – likely POS/MPLS
BUT, if there are other services….…
ATM service
 VC/VP/ L2VPN
 TDM/CEM


This approach is also a low risk approach to building out your next backbone.
ATM COLL is proven technology
 Easily migration to MPLS on same product
 Move entirely to MPLS when ready
 Or, stay in SIN mode for hybrid network

4 Modes of Hybrid Operation
Edge
Con ID
Edge
4 modes: hop by hop; ATM; MPLS, SIN
Payload
Hybrids Redefine Multi-Service
 Multi service past:
 Voice
 Video
 Data
 Multi service now
 POS, ATM, FNNI, IP interface to customer
 Option of MPLS on top of all
 Hybrid acts as adaptation layer
 Connection oriented
 Voice video data
service, enable multi-application uses:
The Effect of Hybrid Switches in the Network Design
POP
Full mesh of SPVCs between
all Core Routers
POP
CR
Many diverse paths exploited
through ATM core
CR
POP
Routers’ View of the Network
CR
CR
POP
POP
CR
CR
POP
ATM Switch
CR
POP
AR
AR
AR
AR
AR
CR
Core IP Router
AR
Access Router /
AS Border Router
Conclusions
 MPLS promises to be a powerful
 Marring the best of IP and ATM
 It will take time to meet all high
 Functional replacement
 Network management
unification technology
expectation.
 MPLS is not vanilla
IP.
 SPs will be very cautious, and will be sure they know what they are
getting when vendors talk about MPLS.
 SPs do require a low risk, simple migration process.

Can not build out a parallel network
 MPLS is just a technology, with great potential
 Must enable new services (revenue)
 Reduce operational burdens (costs)
 Hybrid Switches
enable a low risk migration process, while enabling a
truly multi-service network.
Thank You!