Flow-Based Routing: Towards New QoS Models
Dr. Riad Hartani
Caspian Networks© 2003 Caspian Networks, Inc.

Agenda`

MPLS: status and ongoing work items`

Flow-based routing – the technology`

Flow-based routing benefitsOverall technology benefitsSpecific benefits in an MPLS environment`

Flow-based routing: application examples`

Conclusions

Corporate Overview

2003/10/29 - 2© 2003 Caspian Networks, Inc.

MPLS: Status`

A packet-based transport platform:
For IP Internet traffic
 For private IP traffic (L3 VPN)
 For multi-services traffic (ATM / FR / Ethernet / TDMand L2 VPN)``

Corporate Overview

Used jointly with Diffserv to provide QoS
Being augmented with dynamic restoration
schemes and various OAM functionalities

2003/10/29 - 3© 2003 Caspian Networks, Inc.

MPLS: Work in progress

MPLS - a good technology, but some issues remain:






Corporate Overview

Traffic engineering is good for long term timescales, butneed complementary techniques for short term variations
Additional design complexity (and hence cost) in the network
No QoS guarantees yet, even with Diffserv!
Remaining scalability issues (e.g. #LSPs, MBGP RR,Restoration, etc.)
Not an end-to-end solution – and not designed to be soLittle room for differentiation between service providers,when it comes to QoS

2003/10/29 - 4© 2003 Caspian Networks, Inc.

Flow-Based Routing: The Technology
RAM

1. Route each packet
Route Each Packet

2. Switch to output
3. Class-based QoSQueue (Class) & Forward

Flow Router
1. Hash for flow identification••

2M flows/s and 6M flows per 10 Gig
Flexible definition of flows

2. Create “soft” state or look up•RAMRAMRAMRAM

Hash, Look Up State, Route,Store, WFQ/Flow, Switch

Route, switch, filters, stats

Look Up State, Store,WFQ/Flow

3. Per-flow QoS behavior

RAMCorporate Overview

2003/10/29 - 5© 2003 Caspian Networks, Inc.

RAM

Switch Fabric

RAMSwitching
Network

Conventional RouterFlow-Based Routing Overall Benefits`

Network-level
`Novel congestion control and QoS schemes
X Improved DiffServ model with enhanced Per Hop Behavior
X Scalable IntServ model – Nodal behavior only
X Or … an alternative/evolution of existing IP networks
Optimized for Per-flow dynamic statistics collection
Router based preventive security (IDS/DOS)
Efficient flow based load balancing and dynamic flow aware routing

Node-level


Corporate Overview

Packet processing I/O scaling
Switch fabric scaling and intra-switch load balancing schemes

2003/10/29 - 6© 2003 Caspian Networks, Inc.

Flow-Based Routing QoS-Specific Benefits
Requirement

Conventional
Packet Routers

Flow Based Routers

Protect certain traffic types
from others (voice vs. video,
www vs. P2P, etc.)

No explicit
differentiation oftraffic types

Alternative congestion control schemes
for high rate vs. low rate, responsive vs.
unresponsive, long-lived vs. short lived flows, etc.

Enable ON/OFF service model

Performancedegradation undercongestion`Optimize network good-put &user response timeLimited`

Tight jitter and guaranteed
QoS for real-time applications

Jitter increases withutilization and hopcounts

CAC for flows with guarantees` Guaranteed QoS capabilities (policing/shaping)
for low, constant jitter even at high utilization

Network simplification(cost reduction)

Manual trafficengineering

Increased node intelligence: dynamic resource
management and granular statistics collection

Corporate Overview

2003/10/29 - 7

CAC for UDP flows` Per-flow pre-emption capabilities`

CAC for TCP flows
Alternative congestion control schemes`© 2003 Caspian Networks, Inc.

Flow-Based Routing in an MPLS context`

Two deployment options


LSP is the flowXThe flow is what is carried within the LSP: IP flows or pseudo-Wire flows
X`

State per LSP: scheduling / shaping / policing per LSP

Intra-LSP visibility: dual state per-flow and per-LSPBenefitsCorporate Overview

Granular and deterministic QoS (both for the E-LSP and L-LSP models)
Simplified traffic engineering by increasing node level intelligence
More scalable deployments in terms of # LSPs
More opportunity for service differentiation leveraging state information

2003/10/29 - 8© 2003 Caspian Networks, Inc.

Application – Network Consolidation
Today

Apeiro-Enabled
Optical/Transmission Network

Optical/Transmission Network
IP/MPLS

IP/MPLS

ATMCoreCore Core

Edge

Edge Edge`Internet

Data

Voice

IP, IP VPN

FR, ATM,
IP VPN

Voice &Private Line

Separate Frame and ATM overlay
networks required for premium traffic

Corporate Overview

2003/10/29 - 9Internet`

ATMequivalent
QoS

Metro
Ethernet

Data

Voice

FR, ATM,IP VPN

Voice &Private Line

ATM-like rate, performance & bandwidth guarantees
allow subsuming of ATM and Frame traffic on acommon IP backbone© 2003 Caspian Networks, Inc.

Application – Controlling P2P Traffic

Isolated Congestion Points

P2P Traffic
ISP B Network

ISP A Network• Traffic rates, flow lengths and traffic
per flow potentially used to identify
P2P traffic

Peering• Provides customized control
behavior under congestion• Leads to optimized ROI when it
comes to expensive peering links,
etc.
Corporate Overview

2003/10/29 - 10

© 2003 Caspian Networks, Inc.

Undersea Links

Conclusions`Flow-based routing is a new paradigm thatcombines the best of packet/circuit switching –fits within a native IP network or an MPLS network`Technology has obvious benefits today –a new IP QoS model`

Technology also has other not-so-obvious benefits`

Most importantly, technology has potential ofchanging service providers’ business models

Corporate Overview

2003/10/29 - 11

© 2003 Caspian Networks, Inc.