- •QoS Overview
- •“Do I Know This Already?” Quiz
- •QoS: Tuning Bandwidth, Delay, Jitter, and Loss Questions
- •Foundation Topics
- •QoS: Tuning Bandwidth, Delay, Jitter, and Loss
- •Bandwidth
- •The clock rate Command Versus the bandwidth Command
- •QoS Tools That Affect Bandwidth
- •Delay
- •Serialization Delay
- •Propagation Delay
- •Queuing Delay
- •Forwarding Delay
- •Shaping Delay
- •Network Delay
- •Delay Summary
- •QoS Tools That Affect Delay
- •Jitter
- •QoS Tools That Affect Jitter
- •Loss
- •QoS Tools That Affect Loss
- •Summary: QoS Characteristics: Bandwidth, Delay, Jitter, and Loss
- •Voice Basics
- •Voice Bandwidth Considerations
- •Voice Delay Considerations
- •Voice Jitter Considerations
- •Voice Loss Considerations
- •Video Basics
- •Video Bandwidth Considerations
- •Video Delay Considerations
- •Video Jitter Considerations
- •Video Loss Considerations
- •Comparing Voice and Video: Summary
- •IP Data Basics
- •Data Bandwidth Considerations
- •Data Delay Considerations
- •Data Jitter Considerations
- •Data Loss Considerations
- •Comparing Voice, Video, and Data: Summary
- •Foundation Summary
- •QoS Tools and Architectures
- •“Do I Know This Already?” Quiz
- •QoS Tools Questions
- •Differentiated Services Questions
- •Integrated Services Questions
- •Foundation Topics
- •Introduction to IOS QoS Tools
- •Queuing
- •Queuing Tools
- •Shaping and Policing
- •Shaping and Policing Tools
- •Congestion Avoidance
- •Congestion-Avoidance Tools
- •Call Admission Control and RSVP
- •CAC Tools
- •Management Tools
- •Summary
- •The Good-Old Common Sense QoS Model
- •GOCS Flow-Based QoS
- •GOCS Class-Based QoS
- •The Differentiated Services QoS Model
- •DiffServ Per-Hop Behaviors
- •The Class Selector PHB and DSCP Values
- •The Assured Forwarding PHB and DSCP Values
- •The Expedited Forwarding PHB and DSCP Values
- •The Integrated Services QoS Model
- •Foundation Summary
- •“Do I Know This Already?” Quiz Questions
- •CAR, PBR, and CB Marking Questions
- •Foundation Topics
- •Marking
- •IP Header QoS Fields: Precedence and DSCP
- •LAN Class of Service (CoS)
- •Other Marking Fields
- •Summary of Marking Fields
- •Class-Based Marking (CB Marking)
- •Network-Based Application Recognition (NBAR)
- •CB Marking show Commands
- •CB Marking Summary
- •Committed Access Rate (CAR)
- •CAR Marking Summary
- •Policy-Based Routing (PBR)
- •PBR Marking Summary
- •VoIP Dial Peer
- •VoIP Dial-Peer Summary
- •Foundation Summary
- •Congestion Management
- •“Do I Know This Already?” Quiz
- •Queuing Concepts Questions
- •WFQ and IP RTP Priority Questions
- •CBWFQ and LLQ Questions
- •Comparing Queuing Options Questions
- •Foundation Topics
- •Queuing Concepts
- •Output Queues, TX Rings, and TX Queues
- •Queuing on Interfaces Versus Subinterfaces and Virtual Circuits (VCs)
- •Summary of Queuing Concepts
- •Queuing Tools
- •FIFO Queuing
- •Priority Queuing
- •Custom Queuing
- •Weighted Fair Queuing (WFQ)
- •WFQ Scheduler: The Net Effect
- •WFQ Scheduling: The Process
- •WFQ Drop Policy, Number of Queues, and Queue Lengths
- •WFQ Summary
- •Class-Based WFQ (CBWFQ)
- •CBWFQ Summary
- •Low Latency Queuing (LLQ)
- •LLQ with More Than One Priority Queue
- •IP RTP Priority
- •Summary of Queuing Tool Features
- •Foundation Summary
- •Conceptual Questions
- •Priority Queuing and Custom Queuing
- •CBWFQ, LLQ, IP RTP Priority
- •Comparing Queuing Tool Options
- •“Do I Know This Already?” Quiz
- •Shaping and Policing Concepts Questions
- •Policing with CAR and CB Policer Questions
- •Shaping with FRTS, GTS, DTS, and CB Shaping
- •Foundation Topics
- •When and Where to Use Shaping and Policing
- •How Shaping Works
- •Where to Shape: Interfaces, Subinterfaces, and VCs
- •How Policing Works
- •CAR Internals
- •CB Policing Internals
- •Policing, but Not Discarding
- •Foundation Summary
- •Shaping and Policing Concepts
- •“Do I Know This Already?” Quiz
- •Congestion-Avoidance Concepts and RED Questions
- •WRED Questions
- •FRED Questions
- •Foundation Topics
- •TCP and UDP Reactions to Packet Loss
- •Tail Drop, Global Synchronization, and TCP Starvation
- •Random Early Detection (RED)
- •Weighted RED (WRED)
- •How WRED Weights Packets
- •WRED and Queuing
- •WRED Summary
- •Flow-Based WRED (FRED)
- •Foundation Summary
- •Congestion-Avoidance Concepts and Random Early Detection (RED)
- •Weighted RED (WRED)
- •Flow-Based WRED (FRED)
- •“Do I Know This Already?” Quiz
- •Compression Questions
- •Link Fragmentation and Interleave Questions
- •Foundation Topics
- •Payload and Header Compression
- •Payload Compression
- •Header Compression
- •Link Fragmentation and Interleaving
- •Multilink PPP LFI
- •Maximum Serialization Delay and Optimum Fragment Sizes
- •Frame Relay LFI Using FRF.12
- •Choosing Fragment Sizes for Frame Relay
- •Fragmentation with More Than One VC on a Single Access Link
- •FRF.11-C and FRF.12 Comparison
- •Foundation Summary
- •Compression Tools
- •LFI Tools
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Call Admission Control Overview
- •Call Rerouting Alternatives
- •Bandwidth Engineering
- •CAC Mechanisms
- •CAC Mechanism Evaluation Criteria
- •Local Voice CAC
- •Physical DS0 Limitation
- •Max-Connections
- •Voice over Frame Relay—Voice Bandwidth
- •Trunk Conditioning
- •Local Voice Busyout
- •Measurement-Based Voice CAC
- •Service Assurance Agents
- •SAA Probes Versus Pings
- •SAA Service
- •Calculated Planning Impairment Factor
- •Advanced Voice Busyout
- •PSTN Fallback
- •SAA Probes Used for PSTN Fallback
- •IP Destination Caching
- •SAA Probe Format
- •PSTN Fallback Scalability
- •PSTN Fallback Summary
- •Resource-Based CAC
- •Resource Availability Indication
- •Gateway Calculation of Resources
- •RAI in Service Provider Networks
- •RAI in Enterprise Networks
- •RAI Operation
- •RAI Platform Support
- •Cisco CallManager Resource-Based CAC
- •Location-Based CAC Operation
- •Locations and Regions
- •Calculation of Resources
- •Automatic Alternate Routing
- •Location-Based CAC Summary
- •Gatekeeper Zone Bandwidth
- •Gatekeeper Zone Bandwidth Operation
- •Single-Zone Topology
- •Multizone Topology
- •Zone-per-Gateway Design
- •Gatekeeper in CallManager Networks
- •Zone Bandwidth Calculation
- •Gatekeeper Zone Bandwidth Summary
- •Integrated Services / Resource Reservation Protocol
- •RSVP Levels of Service
- •RSVP Operation
- •RSVP/H.323 Synchronization
- •Bandwidth per Codec
- •Subnet Bandwidth Management
- •Monitoring and Troubleshooting RSVP
- •RSVP CAC Summary
- •Foundation Summary
- •Call Admission Control Concepts
- •Local-Based CAC
- •Measurement-Based CAC
- •Resources-Based CAC
- •“Do I Know This Already?” Quiz
- •QoS Management Tools Questions
- •QoS Design Questions
- •Foundation Topics
- •QoS Management Tools
- •QoS Device Manager
- •QoS Policy Manager
- •Service Assurance Agent
- •Internetwork Performance Monitor
- •Service Management Solution
- •QoS Management Tool Summary
- •QoS Design for the Cisco QoS Exams
- •Four-Step QoS Design Process
- •Step 1: Determine Customer Priorities/QoS Policy
- •Step 2: Characterize the Network
- •Step 3: Implement the Policy
- •Step 4: Monitor the Network
- •QoS Design Guidelines for Voice and Video
- •Voice and Video: Bandwidth, Delay, Jitter, and Loss Requirements
- •Voice and Video QoS Design Recommendations
- •Foundation Summary
- •QoS Management
- •QoS Design
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •The Need for QoS on the LAN
- •Layer 2 Queues
- •Drop Thresholds
- •Trust Boundries
- •Cisco Catalyst Switch QoS Features
- •Catalyst 6500 QoS Features
- •Supervisor and Switching Engine
- •Policy Feature Card
- •Ethernet Interfaces
- •QoS Flow on the Catalyst 6500
- •Ingress Queue Scheduling
- •Layer 2 Switching Engine QoS Frame Flow
- •Layer 3 Switching Engine QoS Packet Flow
- •Egress Queue Scheduling
- •Catalyst 6500 QoS Summary
- •Cisco Catalyst 4500/4000 QoS Features
- •Supervisor Engine I and II
- •Supervisor Engine III and IV
- •Cisco Catalyst 3550 QoS Features
- •Cisco Catalyst 3524 QoS Features
- •CoS-to-Egress Queue Mapping for the Catalyst OS Switch
- •Layer-2-to-Layer 3 Mapping
- •Connecting a Catalyst OS Switch to WAN Segments
- •Displaying QoS Settings for the Catalyst OS Switch
- •Enabling QoS for the Catalyst IOS Switch
- •Enabling Priority Queuing for the Catalyst IOS Switch
- •CoS-to-Egress Queue Mapping for the Catalyst IOS Switch
- •Layer 2-to-Layer 3 Mapping
- •Connecting a Catalyst IOS Switch to Distribution Switches or WAN Segments
- •Displaying QoS Settings for the Catalyst IOS Switch
- •Foundation Summary
- •LAN QoS Concepts
- •Catalyst 6500 Series of Switches
- •Catalyst 4500/4000 Series of Switches
- •Catalyst 3550/3524 Series of Switches
- •QoS: Tuning Bandwidth, Delay, Jitter, and Loss
- •QoS Tools
- •Differentiated Services
- •Integrated Services
- •CAR, PBR, and CB Marking
- •Queuing Concepts
- •WFQ and IP RTP Priority
- •CBWFQ and LLQ
- •Comparing Queuing Options
- •Conceptual Questions
- •Priority Queuing and Custom Queuing
- •CBWFQ, LLQ, IP RTP Priority
- •Comparing Queuing Tool Options
- •Shaping and Policing Concepts
- •Policing with CAR and CB Policer
- •Shaping with FRTS, GTS, DTS, and CB Shaping
- •Shaping and Policing Concepts
- •Congestion-Avoidance Concepts and RED
- •WRED
- •FRED
- •Congestion-Avoidance Concepts and Random Early Detection (RED)
- •Weighted RED (WRED)
- •Flow-Based WRED (FRED)
- •Compression
- •Link Fragmentation and Interleave
- •Compression Tools
- •LFI Tools
- •Call Admission Control Concepts
- •Local-Based CAC
- •Measurement-Based CAC
- •Resources-Based CAC
- •QoS Management Tools
- •QoS Design
- •QoS Management
- •QoS Design
- •LAN QoS Concepts
- •Catalyst 6500 Series of Switches
- •Catalyst 4500/4000 Series of Switches
- •Catalyst 3550/3524 Series of Switches
- •Foundation Topics
- •QPPB Route Marking: Step 1
- •QPPB Per-Packet Marking: Step 2
- •QPPB: The Hidden Details
- •QPPB Summary
- •Flow-Based dWFQ
- •ToS-Based dWFQ
- •Distributed QoS Group–Based WFQ
- •Summary: dWFQ Options
Cisco Catalyst Switch QoS Features 713
If the PFC has forwarded the frame into the egress queue, the IP DCSP value and CoS value is set as the frame is placed in the proper transmit queue. If the frame is an 802.1Q or ISL trunk frame, only the CoS value is set as the frame is placed in the proper transmit queue.
Catalyst 6500 QoS Summary
The numerous hardware options available on the Catalyst 6500 offer a wide range of customization. This section summarizes the impact of the hardware choices on the QoS performance of a Catalyst 6500 series switch.
Table 10-8 summarizes the QoS processes of the Catalyst 6500 and lists the component responsible for the function.
Table 10-8 QoS Processess of the Catalyst 6500
QoS Process |
Catalyst 6500 Component That Performs This Function |
|
|
Input scheduling |
Performed by port application-specific integrated circuits (ASICs) |
|
Layer 2 only with or without PFC |
|
|
Classification |
Performed by supervisor or PFC |
|
L2 only is done by supervisor |
|
L2/3 is done by PFC |
|
|
Policing |
Performed by PFC via L3 forwarding engine |
|
|
Packet rewrite |
Performed by port ASICs |
|
L2/L3 based on classification |
|
|
Output scheduling |
Performed by port ASICs |
|
L2/L3 based on classification |
|
|
Table 10-9 describes the supported receive queues of the Catalyst 6500.
Table 10-9 Supported Receive Queues of the Catalyst 6500
Catalyst 6500 |
|
Receive Queues |
Description |
|
|
1q4t |
1 standard queue with 4 tail-drop thresholds |
|
|
1p1q4t |
1 strict-priority queue, 1 standard queue with 4 tail-drop thresholds |
|
|
1p1q0t |
1 strict-priority queue, 1 standard queue with one nonconfigurable (100%) |
|
tail-drop threshold |
|
|
1p1q8t |
1 strict-priority queue, 1 standard queue with 8 configurable WRED-drop |
|
thresholds and 1 nonconfigurable (100%) tail-drop threshold |
|
|
714 Chapter 10: LAN QoS
Table 10-10 describes the supported transmit queues of the Catalyst 6500.
Table 10-10 Supported Transmit Queues of the Catalyst 6500
Catalyst 6500 |
|
Transmit Queues |
Description |
|
|
2q2t |
2 standard queues with 2 tail-drop thresholds per queue |
|
|
1p2q2t |
1 strict-priority queue, 2 standard queues with 2 WRED-drop thresholds per |
|
queue |
|
|
1p3q1t |
1 strict-priority queue, 3 standard queues with 1 WRED-drop threshold and |
|
1 nonconfigurable tail-drop threshold per queue |
|
|
1p2q1t |
1 strict-priority queue, 2 standard queues with 1 WRED-drop threshold and |
|
1 nonconfigurable (100%) tail-drop threshold per queue |
|
|
Table 10-11 lists the supported receive and transmit queues of the Ethernet modules for the Catalyst 6500.
Table 10-11 Supported Receive and Transmit Queues of the Ethernet Modules for the Catalyst 6500
|
Module |
RX Queue |
TX Queue |
RX Queue |
TX Queue |
Ethernet Modules |
Description |
Type |
Type |
Size |
Size |
|
|
|
|
|
|
WS-X6K-S2U-MSFC2 |
All Supervisor |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
WS-X6K-S2-MSFC2 |
Engine II uplink |
|
|
Q1: 64 KB |
Q2: 64 KB |
WS-X6K-S2-PFC2 |
ports |
|
|
|
Q1: 311 KB |
|
|
|
|
||
|
|
|
|
|
|
WS-X6K-S1A-MSFC2 |
All Supervisor |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
WS-X6K-SUP1A-MSFC |
Engine IA uplink |
|
|
Q1: 64 KB |
Q2: 64 KB |
WS-X6K-SUP1A-PFC |
ports |
|
|
|
Q1: 311 KB |
|
|
|
|
||
WS-X6K-SUP1A-2GE |
|
|
|
|
|
|
|
|
|
|
|
WS-X6K-SUP1-2GE |
Supervisor Engine II |
1q4t |
2q2t |
Q1: 80 KB |
Q2: 80 KB |
|
uplink ports |
|
|
|
Q1: 352 KB |
|
|
|
|
|
|
WS-X6524-100FX-MM |
24-port 100BASE- |
1p1q0t |
1p3q1t |
PQ: 6 KB |
PQ: 272 KB |
|
FX fabric-enabled |
|
|
Q1: 22 KB |
Q3: 272 KB |
|
with MT-RJ |
|
|
|
Q2: 272 KB |
|
connectors |
|
|
|
|
|
|
|
|
Q1: 272 KB |
|
|
|
|
|
|
|
|
|
|
|
|
|
WS-X6548-RJ-21 |
48-port |
1p1q0t |
1p3q1t |
PQ: 6 KB |
PQ: 272 KB |
|
10/100BASE-TX |
|
|
Q1: 22 KB |
Q3: 272 KB |
|
fabric-enabled with |
|
|
|
Q2: 272 KB |
|
RJ-21 connectors |
|
|
|
|
|
|
|
|
Q1: 272 KB |
|
|
|
|
|
|
|
|
|
|
|
|
|
Cisco Catalyst Switch QoS Features 715
Table 10-11 Supported Receive and Transmit Queues of the Ethernet Modules for the Catalyst 6500 (Continued)
|
Module |
RX Queue |
TX Queue |
RX Queue |
TX Queue |
Ethernet Modules |
Description |
Type |
Type |
Size |
Size |
|
|
|
|
|
|
WS-X6548-RJ-45 |
48-port 10/ |
1p1q0t |
1p3q1t |
PQ: 6 KB |
PQ: 272 KB |
|
100BASE-TX |
|
|
Q1: 22 KB |
Q3: 272 KB |
|
fabric-enabled with |
|
|
|
Q2: 272 KB |
|
RJ-45 connectors |
|
|
|
|
|
|
|
|
Q1: 272 KB |
|
|
|
|
|
|
|
|
|
|
|
|
|
WS-X6324-100FX-MM |
24-port 100BASE- |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
FX with MT-RJ |
|
|
|
Q1: 90 KB |
|
connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6324-100FX-SM |
24-port 100BASE- |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
FX with MT-RJ |
|
|
|
Q1: 90 KB |
|
connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6348-RJ-45 |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-45 |
|
|
|
|
|
connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6348-RJ21V |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-21 |
|
|
|
|
|
connectors and |
|
|
|
|
|
inline power |
|
|
|
|
|
|
|
|
|
|
WS-X6348-RJ-45V |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-45 |
|
|
|
|
|
connectors and |
|
|
|
|
|
inline power |
|
|
|
|
|
|
|
|
|
|
WS-X6224-100FX-MT |
24-port |
1q4t |
2q2t |
Q1: 8 KB |
Q2: 16 KB |
|
100BASE-FX with |
|
|
|
Q1: 40 KB |
|
MT-RJ connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6248-RJ-45 |
48-port |
1q4t |
2q2t |
Q1: 8 KB |
Q2: 16 KB |
|
10/100BASE-TX |
|
|
|
Q1: 40 KB |
|
with RJ-45 |
|
|
|
|
|
connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6248-TEL |
48-port |
1q4t |
2q2t |
Q1: 8 KB |
Q2: 16 KB |
|
10/100BASE-TX |
|
|
|
Q1: 40 KB |
|
with RJ-21 |
|
|
|
|
|
connectors |
|
|
|
|
|
|
|
|
|
|
continues
716 Chapter 10: LAN QoS
Table 10-11 Supported Receive and Transmit Queues of the Ethernet Modules for the Catalyst 6500 (Continued)
|
Module |
RX Queue |
TX Queue |
RX Queue |
TX Queue |
Ethernet Modules |
Description |
Type |
Type |
Size |
Size |
|
|
|
|
|
|
WS-X6248A-TEL |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-21 |
|
|
|
|
|
connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6148-RJ-45V |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-45 |
|
|
|
|
|
connectors and |
|
|
|
|
|
inline power |
|
|
|
|
|
|
|
|
|
|
WS-X6148-RJ21V |
48-port |
1q4t |
2q2t |
Q1: 16 KB |
Q2: 22 KB |
|
10/100BASE-TX |
|
|
|
Q1: 90 KB |
|
with RJ-21 |
|
|
|
|
|
connectors and |
|
|
|
|
|
inline power |
|
|
|
|
|
|
|
|
|
|
WS-X6024-10FL-MT |
24-port |
1q4t |
2q2t |
Q1: 8 KB |
Q2: 16 KB |
|
10BASE-FL with |
|
|
|
Q1: 40 KB |
|
MT-RJ connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6816-GBIC |
16-port |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
|
1000BASE-X |
|
|
Q1: 64 KB |
Q2: 64 KB |
|
dual-fabric with |
|
|
|
Q1: 311 KB |
|
GBIC connectors |
|
|
|
|
|
|
|
|
|
|
|
and onboard DFC |
|
|
|
|
|
|
|
|
|
|
WS-X6516-GBIC |
16-port |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
|
1000BASE-X with |
|
|
Q1: 64 KB |
Q2: 64 KB |
|
GBIC connectors |
|
|
|
Q1: 311 KB |
|
|
|
|
|
|
|
|
|
|
|
|
WS-X6516-GE-TX |
16-port 10/100/ |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
|
100BASE-T with |
|
|
Q1: 64 KB |
Q2: 64 KB |
|
RJ-45 connectors |
|
|
|
Q1: 311 KB |
|
|
|
|
|
|
|
|
|
|
|
|
WS-X6408-GBIC |
8-port |
1q4t |
2q2t |
Q1: 80 KB |
Q2: 80 KB |
|
1000BASE-X with |
|
|
|
Q1: 352 KB |
|
GBIC connectors |
|
|
|
|
|
|
|
|
|
|
WS-X6408A-GBIC |
8-port |
1p1q4t |
1p2q2t |
PQ: 9 KB |
PQ: 64 KB |
|
1000BASE-X with |
|
|
Q1: 64 KB |
Q2: 64 KB |
|
GBIC connectors |
|
|
|
Q1: 311 KB |
|
|
|
|
|
|
|
|
|
|
|
|