End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new packets that are dropped when the queue size is at the maximum threshold. In the preceding example, the mark probability denominator indicates that all IP precedence levels will have 1 of every 10 packets dropped when the average queue depth equals the maximum threshold.
In the show queueing output, notice that the minimum threshold is different for each IP precedence level. It was previously mentioned that it is possible to modify the configuration so that all IP precedence or DSCP values are treated the same. Example 2-2 shows one way to do this.
Example 2-2. Configuring WRED Parameters on a Cisco IOS Router Interface
Router(config)#interface s6/0
Router(config-if)#random-detect precedence 1 ? <1-4096> minimum threshold (number of packets)
Router(config-if)#random-detect precedence 1 20 ? <1-4096> maximum threshold (number of packets)
Router(config-if)#random-detect precedence 1 20 40 ? <1-65535> mark probability denominator
<cr>
Router(config-if)#random-detect precedence 1 20 40 10 Router(config-if)#random-detect precedence 2 20 40 10 Router(config-if)#random-detect precedence 3 20 40 10 Router(config-if)#random-detect precedence 4 20 40 10 Router(config-if)#random-detect precedence 5 20 40 10 Router(config-if)#random-detect precedence 6 20 40 10 Router(config-if)#random-detect precedence 7 20 40 10 Router(config-if)#exit
Router(config)#exit
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new Router#show queueing interface s6/0
Interface Serial6/0 queueing strategy: random early detection (WRED) Exp-weight-constant: 9 (1/512)
Mean queue depth: 0
class Random drop Tail drop Minimum Maximum Mark pkts/bytes pkts/bytes thresh thresh prob 0 0/0 0/0 20 40 1/10 1 0/0 0/0 20 40 1/10 2 0/0 0/0 20 40 1/10 3 0/0 0/0 20 40 1/10 4 0/0 0/0 20 40 1/10 5 0/0 0/0 20 40 1/10 6 0/0 0/0 20 40 1/10 7 0/0 0/0 20 40 1/10 rsvp 0/0 0/0 37 40 1/10
As you can see from the show queueing output, the minimum threshold, maximum threshold, and mark probability denominator are now the same for all IP precedence values. This is not necessarily recommended; instead, it is shown to illustrate that the treatment of packets is entirely user configurable.
It is also possible to use DSCP-based WRED, and the configuration options for that differ slightly, as demonstrated in Example 2-3.
Example 2-3. Configuring DSCP-based WRED on a Cisco IOS Router Interface
Router(config)#interface s6/0 Router(config-if)#random-detect ?
dscp-based Enable dscp based WRED on an interface prec-based Enable prec based WRED on an interface
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new <cr>
Router(config-if)#random-detect dscp-based Router(config-if)#random-detect ?
dscp parameters for each dscp value
dscp-based Enable dscp based WRED on an interface exponential-weighting-constant weight for mean queue depth calculation flow enable flow based WRED
prec-based Enable prec based WRED on an interface precedence parameters for each precedence value <cr>
Router(config-if)#random-detect dscp ?
<0-63> Differentiated services codepoint value af11 Match packets with AF11 dscp (001010) af12 Match packets with AF12 dscp (001100) af13 Match packets with AF13 dscp (001110) af21 Match packets with AF21 dscp (010010) af22 Match packets with AF22 dscp (010100) af23 Match packets with AF23 dscp (010110) af31 Match packets with AF31 dscp (011010) af32 Match packets with AF32 dscp (011100) af33 Match packets with AF33 dscp (011110) af41 Match packets with AF41 dscp (100010) af42 Match packets with AF42 dscp (100100) af43 Match packets with AF43 dscp (100110)
cs1 Match packets with CS1(precedence 1) dscp (001000) cs2 Match packets with CS2(precedence 2) dscp (010000) cs3 Match packets with CS3(precedence 3) dscp (011000)
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new cs4 Match packets with CS4(precedence 4) dscp (100000)
cs5 Match packets with CS5(precedence 5) dscp (101000) cs6 Match packets with CS6(precedence 6) dscp (110000) cs7 Match packets with CS7(precedence 7) dscp (111000) default Match packets with default dscp (000000)
ef Match packets with EF dscp (101110) rsvp rsvp traffic
Router(config-if)#random-detect dscp af11 ?
<1-4096> minimum threshold (number of packets)
Router(config-if)#random-detect dscp af11 20 ? <1-4096> maximum threshold (number of packets)
Router(config-if)#random-detect dscp af11 20 40 ? <1-65535> mark probability denominator
<cr>
Router(config-if)#random-detect dscp af11 20 40 10 ? <cr>
Router(config-if)#random-detect dscp af11 20 40 10 Router(config-if)#exit
Router(config)#exit
Router#show queueing interface s6/0
Interface Serial6/0 queueing strategy: random early detection (WRED) Exp-weight-constant: 9 (1/512)
Mean queue depth: 0
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new dscp Random drop Tail drop Minimum Maximum Mark
pkts/bytes pkts/bytes thresh thresh prob af11 0/0 0/0 20 40 1/10 af12 0/0 0/0 28 40 1/10 af13 0/0 0/0 24 40 1/10 af21 0/0 0/0 33 40 1/10 af22 0/0 0/0 28 40 1/10 af23 0/0 0/0 24 40 1/10 af31 0/0 0/0 33 40 1/10 af32 0/0 0/0 28 40 1/10 af33 0/0 0/0 24 40 1/10 af41 0/0 0/0 33 40 1/10 af42 0/0 0/0 28 40 1/10 af43 0/0 0/0 24 40 1/10 cs1 0/0 0/0 22 40 1/10 cs2 0/0 0/0 24 40 1/10 cs3 0/0 0/0 26 40 1/10 cs4 0/0 0/0 28 40 1/10 cs5 0/0 0/0 31 40 1/10 cs6 0/0 0/0 33 40 1/10 cs7 0/0 0/0 35 40 1/10 ef 0/0 0/0 37 40 1/10 rsvp 0/0 0/0 37 40 1/10 default 0/0 0/0 20 40 1/10
The show queueing output for af21, af31, and af41 indicates that the minimum threshold for af11 would have been 33 by default. As shown, the minimum threshold is 20, based on commands entered.
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new
NOTE
The afxx values shown in the show queueing output are related to the assured forwarding per-hop behavior (AF PHB) discussed in Chapter 1. From the show queueing output, you can see that afx3 packets will be dropped before afx2 packets, and afx2 packets will be dropped before afx1 packets. This behavior was explained in detail in Chapter 1.
Incidentally, the term average queue depth has been used several times during this discussion of WRED and, although a detailed explanation of this formula is beyond the scope of this chapter, the formula used to calculate average queue depth is as follows:
Average = (old_average * (1 – 2 -n)) + (current_queue_size * 2 -n), where n is the exponential weight factor, which is user configurable.
CAUTION
If the value for n is set too high, WRED will not work properly and the net impact will be roughly the same as if WRED were not in use at all.
At time of publication, the Catalyst 3550 Family and Catalyst 6500 Family of switches support the WRED congestion management feature. Refer to the congestion management section in each product chapter for the Catalyst 3550 Family and Catalyst 6500 Family of switches for more details.
• Table of Contents
• Index
Cisco Catalyst QoS: Quality of Service in Campus Networks By Mike Flannagan CCIE® No. 7651, Richard Froom CCIE No. 5102, Kevin Turek CCIE No. 7284
Publisher: Cisco Press Pub Date: June 06, 2003
ISBN: 1-58705-120-6 Pages: 432
End-to-end QoS deployment techniques for Cisco Catalyst series switches
Examine various QoS components, including congestion management, congestion
avoidance, shaping, policing/admission control, signaling, link efficiency mechanisms, and classification and marking
Map specified class of service (CoS) values to various queues and maintain CoS values through the use of 802.1q tagging on the Cisco Catalyst 2900XL, 3500XL and Catalyst 4000 and 2948G/2980G CatOS Family of Switches
Learn about classification and rewrite capabilities and queue scheduling on the Cisco Catalyst 5000
Implement ACLs, ACPs, ACEs, and low-latency queuing on the Cisco Catalyst 2950 and 3550 Family of Switches
Understand classification, policying, and scheduling capabilities of the Catalyst 4000 and 4500 IOS Family of Switches
Configure QoS in both Hybrid and Native mode on the Catalyst 6500 Family of Switches Utilize Layer 3 QoS to classify varying levels of service with the Catalyst 6500 MSFC and Flexwan
Understand how to apply QoS in campus network designs by examining end-to-end case studies
Quality of service (QoS) is the set of techniques designed to manage network resources. QoS refers to the capability of a network to provide better service to selected network traffic over various LAN and WAN technologies. The primary goal of QoS is to provide flow priority, including dedicated bandwidth, controlled jitter and latency (required by some interactive and delay-sensitive traffic), and improved loss characteristics.
While QoS has become an essential technology for those organizations rolling out a new