Design of QoS Router

Terrance Lee

Broadband Internet Architecture

Intelligent AccessElectronic Switch(Intserv or Diffserv)

• Switching /Routing• QoS• Security

CoreNetwork

Access Network

Optimized for speed

Packet over Sonet (Diffserv)(IP/PPP/Sonet/DWDM)

All Optical Network (MPLS)

Access Network

Access Network Access

Network

Content Provider

Core Network

• Optical Switch

• Cache Server for Content Providers

• Label Distribution

• Traffic Engineering

Access Network• Cache Server for Content Providers• QoS Router

- Control PlaneQoS Routing

RSVP

Admission Control

- Data PlaneQoS Mechanisms

Measurements

Switch Fabric

- Management PlaneQoS Service Management

Admission Control

• Bandwidth allocation in access networks• Heavily depends on the adopted service scheduling

algorithm (e.g., WFQ, Rate Monotonic)• Trade off between complexity and utilization

QoS Mechanisms• Packet Classifier

• Meter

• Marker

• Dropper

• Queue Manager

• Shaper

• Scheduler

PHY

MAC

FrameEngine

Packet Classifier

SearchEngine

MeterMarkerDropper

QueueManager

Shaper/Scheduler

Memory

Memory

Modifier

Header Payload

TTL FCS

Protocol Conversion

CompressionAuthentication

Encryption

Memory

RSVP QoS Routing Admission Control

Network PlanningManagement

Control

Data

Switch Fabric

or

MAC

QoS Measurement

QoS Service Management

Packet Classifier

• Purposes

- QoS Guarantee

- Security

- Billing

- etc.

Packet Classifier

• Behavior Aggregate• IPv4 Multi-Field-5• IPv4-Multi-Field-6• IEEE 802 MAC• IEEE 802.1p• IEEE 802.1q• IPv6 Multi-Field-5• IPv6 Multi-Field-6• Free Form

Packet Classifier

• Hash Bucket• 64 Rules• Src and Dest IP Addresses: Prefix Match• Src and Dest Port Numbers: Range Match• Protocol ID: Exact Match• 20 Bytes/Rule (Include Valid Time Period and Outpu

t)• Memory Size: ~ 4K Bytes• Wire Speed Classification: ~ 5 Mpps (32-bit Bus @ 10

0MHz) (4 Reads)

Meter

• Average Rate Meter

Parameters: average rate, delta interval

• EWMA Meter

Parameters: average rate, delta interval, gain

• Token Bucket Meter (srTCM, trTCM)

Parameters: CIR, PIR, CBS, PBS, EBS

Meter

• 64 Token Bucket Entries

• Memory Size: ~ 256Bytes

• Stored Parameters: Bucket Size, Bucket Occupancy, Leaky Rate, Scaling Factor

• Wire Speed Metering: ~ 5 Mpps (32-bit Bus @100MHz) (3 Reads, 1 Write)

Marker

• An Optional Service• When TRUE, Remark the Attribute Field for All

Traffic• When FALSE, Remark Only Unmarked Traffic• Attribute Field TOS Byte DSCP Field IEEE 802.1p Priority Field Proprietary (User Defined)

Marker

• 4 Priority Queues

• 3 Levels of Drop Precedence

Dropper

• Drop from Head

• Drop from Tail

• RED

• WRED

• FRED

• Always Drop

• User Defined

Criteria for Dropping

• Queue Threshold

• Arrival Rate

• Other

Drop Metric

• IP Precedence

• DSCP Value

• IEEE 802.1p Priority Value

• RSVP Session

• Queue Depth

• Packet Arrival Rate

• Other

Scheduler

• FIFO (First In First Out)

• SP (Strict Priority)

• WFQ (Weighted Fair Queuing)

• SP/WFQ

• WRR (Weighted Round Robin)

• Priority Bandwidth (Priority with Maximum Burst Constraint)

Scheduler

• Configurable Number of Queues under Strict Priority

• Weights of WFQ: 0-63

• Up to 4 Queues

Shaper

• An Optional Service

• Per-Class Token Bucket Traffic Shaping

• srTC and trTC shaping

• SLA Guarantee

• When Enabled, Service Becomes

Non-Work-Conserving

Summary

• We Prototyped a Router with Complete QoS Mechanisms

• Future Work: IPSec, MPLS Capability