mpls deployment examining the network evolution. agenda overview of the existing network...
TRANSCRIPT
MPLS DeploymentExamining 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 DesignPotential MPLS Networks
Current Design Practices and Market ForcesRequirements Met by Current Designs
Product Functionality by ProductConstraints 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
T ier 1M ajor C arrie rs
PopContent
Access
Access
ContentCore Router
Core Router
Access Router
Access Router
Access Router
Access Router
Access Router
Access Router
Switch
SwitchSwitchSwitch
SwitchSwitch
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: Multiple tiers
Bandwidth Capacity
Value-add lock-ins, enabled by connection oriented link layer: 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
IP Routers: Classify Traffic Forward IP
ATM Switches Provide Raw Switching Capacity Provides connection-oriented link
layer, that enables: Traffic Engineering Hard QoS Traffic management Constraint-Based / Congestion-
aware routing
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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 NetworkingComparisons of COLLs
The Evolution of IP ProductsSoftware and Protocol Requirements
Hardware RequirementsNetwork 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. MPLS enables to COLL behavior.
The pinned-up connection is relatively permanent, thereby allowing for resources to be reserved and allocated. Traffic Engineering, QoS and Congestion Aware Routing
Service Providers with an existing COLL will require MPLS to be a functional replacement.
The charts below reflect that MPLS is providing the key components of a COLL technology.
MPLS and ATM as COLLs
ATM MPLS Connection ID VP / VC (2) Stacked Labels (many)
Connection Method Virtual Circuits
Label Switched Paths (LSPs)
Explicit Routing Designated Transit List
Explicit Route Objects
Path Setup UNI Signaling
CR-LDP or RSVP-TE
To meet QoS requirements, even non-ATM LSRs should provide capabilities similar to ATM switches:
ATM MPLSQueuing Per-VC queuing Per-LSP queuing
TrafficScheduling
Weighted per-VCscheduling
Weighted per-LSP scheduling
QoS Routing 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 over-
subscription) 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
Connection oriented Networking
Traditional Routing IP Routing and forwarding
MPLS Connections for IP
Connection Switching
Connectionless Packet Routing
IP ATM
MPLS
ATM already has the right experience with the necessary algorithms.Connection types: Is your MPLS vendor delivering 1994 technology?
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 ModelMoving to an End-to-end MPLS Network
The Migration Process
AAL5Header Fixed 53 byte MTU
AAL5Header Dynamic MTU up to 16k
PPPHeader Dynamic MTU up to 16k
Encapsulation and MTU Routing Protocol
OSPF, RIP,
IS-IS, BGP
P-NNI
P-NNI
Technology
ATM
F-NNI
POS
ATMCells
ATMCellsF-NNI
Easy migration IP/ATM/cells Today IP/ATM/FNNI HW IP/MPLS/FNNI SW IP/MPLS/POS SW
Each step is a fully functional network.
What is not shown is that you lose your COLL….which is why you need to add MPLS back on top.
The New Services Enabled by an MPLS Infrastructure
Advantages of MPLS NetworkingNew Services Enabled By MPLS
Hybrid Switches Created by MPLSConclusions
Advantages of MPLS network Transport technology independent End to end connections COLL in single control plane
TE TM QoS CR
Greater tunnel hierarchy N2 adjacencies gone Minimizes IP lookup process
Intelligence at edge Core can be simpler switches
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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 VC, VP, POS, MPLS, Frame Relay…
Only ATM switches can operate in SIN mode 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
Edge
4 modes: hop by hop; ATM; MPLS, SIN
PayloadCon ID
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 service, enable multi-application uses: Voice video data
The Effect of Hybrid Switches in the Network Design
Routers’ View of the Network
Full mesh of SPVCs between all Core Routers
Many diverse paths exploited through ATM core
CR
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ATM Switch
Core IP Router
Access Router /AS Border Router
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Conclusions
MPLS promises to be a powerful unification technology Marring the best of IP and ATM
It will take time to meet all high expectation. Functional replacement Network management
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!