© 1999, Cisco Systems, Inc. 6-1 QoS Chapter 6

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-2 Objectives Upon completion of this chapter, you will be able to perform the following tasks: Discuss Quality of Service Policies Discuss the Service Class Templates

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-3 Topics IP QoS Concepts IP+ATM QOS implementation: 8650 MPLS Command Line Interface

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-4 © 1999, Cisco Systems, Inc IP QoS Concepts

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-5 Network Architecture Conventional Router Label Edge Routers ATM-LSR Label Switching Router (LSR) Note: End to end service is IP; therefore, IP quality of service is what MPLS must support

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-6 Three Components of QOS Concepts Packet Classification Policy Transmit Queue Scheduling Policy Transmit Queue Drop Policy

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-7 MPLS COS Differentiated Services ‘Differentiated Services’ approach: Classification: Set IP precedence at edge Scheduling: WFQ by class Transmit Drop: WRED by class Result: Provision for statistical delivery of high precedence traffic

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-8 Switching rx queue tx queue Tail DropFIFO tx hw rx hw No QoS: No Packet Classification Policy Scheduling Policy: Transmit Queue FIFO Transmit Queue Tail Drop Policy

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-9 Classification: Committed Access Rate (CAR) Used by router to classify received packets A flexible precedence setting mechanism —Set precedence based on TCP and IP headers and conformance to a token bucket —Uses Access-list logic to match packets —Primary function: identify packets within profile and mark them at appropriate precedence value

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-10 Drop Policy: Weighted Random Early Detection Manages queues that develop in routers during congestion Discards so that TCP windows are decreased, slowing ingress rate from application Provides RED benefits (shorter queues, improved fairness) Drops most from heaviest users, and from lower Precedence P(drop) Q avg

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-11 Scheduling Policy: Weighted Fair Queuing (WFQ) WFQ schedules transmission of packets during congestion Allocates link bandwidth to class by weight Unused bandwidth is available for other classes Provides bounded delay

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-12 MPLS Class of Service On non-ATM LSRs, it’s simple: Copy IP precedence to MPLS COS field Use MPLS COS as input to WRED Net result is end-to-end QOS indistinguishable from non-MPLS network. LERs connected to ATM and ATM-LSRs are the hard part.

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-13 COS on ATM-LSRs Two challenges: No WRED in switches No COS field in cell header Three modes: ATM Forum PVC Single ‘VC’ (LSP) Multi-’VC’ (LSP)

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-14 ATM Forum PVC mode Usually used in non-MPLS enabled ATM core Looks like a packet interface to MPLS CoS BW and other parameters configured on the PVC Requires significant amount of configuration PVC

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-15 Multi-VC mode MPLS ATM core provides MPLS CoS at each link by establishing parallel LVCs (up to 4) Classification at MPLS ATM edge based on IP precedence Scheduling Policy can assign weight to each class on per- link basis Drop policy can use switch pre-existing discard thresholds mechanisms on switches MPLS ‘LVCs’

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-16 Multi-VC mode example Queuing on all links is per-class WFQ E.g. Premium gets 80% of link, Standard gets 20% –Effect is to make premium see unloaded network Unused b/w available to other classes No per-router-pair configuration required

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-17 MPLS ‘VC’ Single ABR ‘VC’ mode ABR control algorithms are enabled on LSRs ATM-LSRs push back on edge LSRs to eliminate congestion in ATM-LSR cloud non-ATM-LSRs respond to ABR feedback, manage per-VC queues using WRED, WFQ Drop decisions made where MPLS COS is visible - outside the ATM-LSR cloud.

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-18 Single VC Mode ABR parameters MCR is effectively zero (to avoid loss/blocking) Division of bandwidth among competing VCs may be uniform or configured

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-19 Single VC Mode Example A B Chicago New York Nowheresville Tinytown Fair sharing of link A-B is not always desirable Configure relative bandwidth on router-pair basis, e.g. Tinytown-Nowheresville = 1; Chicago-New York = 100 Relative BW carried in TDP, used by ABR algorithms

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-20 © 1999, Cisco Systems, Inc IP+ATM QOS implementation: 8650 QBIN and SCT

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-21 COS in BPX Switches Classification is at MPLS-ATM edge: Up to 4 LVC’s created per dest. prefix, based on TOS Scheduling Policy on BXMs based on weights given to each TOS Drop Policy based on cell discard features of QBINs

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-22 Scheduling Policy: 8650 QBINs 16 COS QBINs per interface AutoRoute created VCs are placed into QBIN based on service type CBR in QBIN 1, VBR in QBIN 2, etc. MPLS uses QBINs 10-14

© 1999, Cisco Systems, Inc. CMPLS 1.0— separate queues CBR UBR ABR ATM Queues IP Queues Class 1 Class 2 Class 3 IP Awareness in an IP+ATM Switch ATM Partition: Bandwidth allocated by VC MPLS Partition: Bandwidth allocated by class Separate labels per class

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-24 Step 1: Define buffering Step 2: Define bandwidth 50% 35% 15% Gold Silver Bronze Guaranteed: latency, delivery Guaranteed: delivery Best effort Class-Based WFQ: QoS Guarantees and Bandwidth Efficiency Weights guarantee minimum bandwidth Buffering controls latency Unused capacity is shared amongst the other classes proportional to their weights Each queue can be separately configured for QoS (e.g. ABR) Benefits: maximize transport of paying traffic no loss of service class guarantees no wasted bandwidth as with PVCs

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-25 Maximizing Bandwidth Utilization Class-based WFQ: feature in Cisco IP+ATM switches Each class is given guaranteed minimum bandwidth If additional bandwidth is available each class can access a prioritized share Used to manage available bandwidth between MPLS and ATM as well as individual IP and ATM service classes For MPLS, applies to either ABR or Multi-TVC models Unused BW Sub-class 1 Minimum BW = n Time Sub-class 2 Minimum BW = 2n Sub-class 3 Minimum BW = n Bandwidth 2n n n

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-26 BPX Drop Policy Each QBIN has CLP low and high thresholds that define when cells should be discarded Thresholds can be set on each QBIN

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-27 Service Class Template (SCT) Provide a means of inferring extended parameters, which are generally platform-specific, from the set of standard ATM protocol parameters passed in VSI connection set-up primitives. Provide support for different classes of service, I.E. MPLS COS 0, MPLS COS 1, etc.

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-28 SCT Definition Service Templates have pre-defined, non-changeable values which are suited to typical interface uses A set of Service Templates are stored on each switch, and are downloaded to the interface service modules as needed In 9.2.1, 3 templates are supported: template 1 is for MPLS, 2 for UNI-ATMF, and 3 for NNI-ATMF

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-29 SCT Definition (cont.) Service Templates contain two classes of data: One class consists of parameters necessary to establish a connection (i.e. per-VC) The second class of data items includes those necessary to configure the associated Class- of-Service Buffers that provide QoS support LSC Configuration

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-30 SCT VC Parameters

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-31 SCT QBIN Parameters

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-32 © 1999, Cisco Systems, Inc QoS Configuration

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-33 A sample network A checklist of BPX and IOS configuration commands The configuration for the sample network, with command explanations and supporting dsp and show commands Configuration

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-34 Sample Network bpx3bpx2 bpx mgx2 mgx1 mgx rtr2rtr3 rtr1

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-35 Classification: Multi-VC mode (3 Steps) 1. Create COS map to correlate IP precedence to MPLS COS 2. Enable multi-vc mode on subinterfaces at MPLS-ATM edge tag-switching atm multi-vc

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-36 Classification: Multi-VC mode (3 Steps) 3. Customize COS map, if desired Create COS map to define precedence-to- MPLS COS correlation Create ACL to match packets Create prefix map to connect COS map and ACL

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-37 Review: Existing RPM2 Configuration Hostname rpm1 ip cef rpmrscprtn par ! addcon vpc switch 9/ rslot ! Interface loopback 0 ip address ! Interface switch 9/1 ! Next sub is the sub connected to the LSC Interface switch 9/1.4 tag-switching ip unnumbered loopback 0 atm pvc aal5snap tag-switching atm vp-tunnel 11 tag-switching ip ! router eigrp 1 network

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-38 Classification: Multi-VC Mode (3 Steps)—Step 1 router#sho tag cos-map 1 cos-map 1 class tag-VC 3 control 2 premium 1 standard 0 available router#sho tag cos-map 1 cos-map 1 class tag-VC 3 control 2 premium 1 standard 0 available ! Some commands from config review slide omitted to allow more space... Hostname rpm1 ip cef ! rpmrscprtn par ! tag-switching cos-map 1 ! addcon vpc switch 9/ rslot ! Interface loopback 0 ip address ! Interface switch 9/1 ! Next sub is the sub connected to the LSC Interface switch 9/1.4 tag-switching ip unnumbered loopback 0 atm pvc aal5snap tag-switching atm vp-tunnel 11 tag-switching ip ! router eigrp 1 network

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-39 Classification: Multi-VC Mode (3 Steps)—Step 2 ! Some commands from config review slide omitted to allow more space... Hostname rpm1 ip cef ! rpmrscprtn par ! tag-switching cos-map 1 ! addcon vpc switch 9/ rslot ! Interface loopback 0 ip address ! Interface switch 9/1 ! Next sub is the sub connected to the LSC Interface switch 9/1.4 tag-switching ip unnumbered loopback 0 atm pvc aal5snap tag-switching atm vp-tunnel 11 tag-switching ip tag-switching atm multi-vc ! router eigrp 1 network

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-40 Classification: Multi-VC Mode (3 Steps)—Step 3 ! Some commands from config review slide omitted to allow more space... ! tag-switching cos-map 1 class 3 premium class 2 available class 1 available class 0 available ! addcon vpc switch 9/ rslot ! Interface loopback 0 ip address ! Interface switch 9/1 ! Next sub is the sub connected to the LSC Interface switch 9/1.4 tag-switching ip unnumbered loopback 0 atm pvc aal5snap tag-switching atm vp-tunnel 11 tag-switching ip tag-switching atm multi-vc ! router eigrp 1 network router#show tag cos-map 1 cos-map 1 class tag-VC 3 premium 2 available 1 available 0 available router#show tag cos-map 1 cos-map 1 class tag-VC 3 premium 2 available 1 available 0 available

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-41 Classification: Multi-VC mode (3 Steps)—Step 3 (cont.) Assign cos-map to IP prefix using IP access list (multiple prefix-maps may be assigned): router#sho ip access-list 1 Standard IP access list 1 permit , wildcard bits router#sho tag cos-map 2 cos-map 2 class tag-VC 3 control 2 premium 1 available 0 available router(config)#tag-switching prefix-map 1 access-list 1 cos-map 2

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-42 Scheduling: BPX (3 Steps)—Steps 1 and 2 1. Confirm and/or assign SCT 1 to each trunk on BPX cnfvsiif 2. On LSC, Assign % weights to each COS on each xtagatm extended port tag-switching atm cos

© 1999, Cisco Systems, Inc. CMPLS 1.0— On BPX, change QBIN discard threshold to affect latency cnfqbin Scheduling: BPX (3 Steps)—Step 3

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-44 Interface 1/0 Sample Network Trunk Numbers LSC1 bpx1 Trunk 2.8 bpx2 LSC2 bpx3 LSC3 Trunk 2.6 RPM PXM mgx1 RPM PXM mgx3 Trunk 2.3 RPM PXM mgx3 Trunk 2.6 Interface 1/0 Trunk 2.8 Interface 2/0 Trunk 2.8

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-45 ! On LSC2: ip cef ! interface atm 1/0 tag-control-protocol vsi id 1 ! interface loopback 0 ip address interface XTagATM21 ip unnumbered Loopback0 extended-port ATM1/0 bpx 2.1 tag-switching ip ! interface XTagATM41 ip unnumbered Loopback0 extended-port ATM1/0 bpx 4.1 tag-switching ip ! router eigrp 1 network Review: LSC Configuration

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-46 Scheduling: BPX (3 Steps)—Step 1 wegb134 TN StrataCom BPX June :05 GMT Trunk: 4.1 Service Class Template ID: 2 Last Command: dspvsiif 4.1 Next Command: wegb134 TN StrataCom BPX June :05 GMT Trunk: 4.1 Service Class Template ID: 2 Last Command: dspvsiif 4.1 Next Command: wegb134 TN StrataCom BPX June :07 GMT Trunk: 4.1 Service Class Template ID: 1 This Command: cnfvsiif wegb134 TN StrataCom BPX June :07 GMT Trunk: 4.1 Service Class Template ID: 1 This Command: cnfvsiif 4.1 1

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-47 Scheduling: BPX (3 Steps)—Step 2 ! On LSC2: ip cef ! interface atm 1/0 tag-control-protocol vsi id 1 ! interface loopback 0 ip address ! interface XTagATM21 ip unnumbered Loopback0 extended-port ATM1/0 bpx 2.1 tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 25 tag-switching atm cos standard 15 tag-switching atm cos available 10 interface XTagATM41 ip unnumbered Loopback0 extended-port ATM1/0 bpx 1.5 tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 25 tag-switching atm cos standard 15 tag-switching atm cos available 10 interface XTagATM261 ip unnumbered Loopback0 extended-port ATM1/0 bpx tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 25 tag-switching atm cos standard 15 tag-switching atm cos available 10

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-48 Scheduling: BPX (3 Steps)—Step 3 wegb134 TN StrataCom BPX June :56 GMT Qbin Database 4.1 on BXM qbin 10 (Configured by MPLS1 Template) (EPD Enabled on this qbin) Qbin State: Enabled Discard Threshold: cells EPD Threshold: 95% High CLP Threshold: 100% EFCI Threshold: 100% Last Command: dspqbin Next Command: wegb134 TN StrataCom BPX June :56 GMT Qbin Database 4.1 on BXM qbin 10 (Configured by MPLS1 Template) (EPD Enabled on this qbin) Qbin State: Enabled Discard Threshold: cells EPD Threshold: 95% High CLP Threshold: 100% EFCI Threshold: 100% Last Command: dspqbin Next Command:

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-49 Example Summary Configuration for MGX2 and BPX2 Default classification on MPLS-ATM edge (MGX2) No changes to BPX QBIN settings QBINs set to 50/30/15/5 for control, premium, standard, and available

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-50 Example: RPM2 tag-switching cos-map 1 class 3 premium class 2 available class 1 available class 0 available ! Interface switch 9/1 ! Next sub is the sub connected to the LSC Interface switch 9/1.4 tag-switching ip unnumbered loopback 0 atm pvc aal5snap tag-switching atm vp-tunnel 11 tag-switching ip tag-switching atm multi-vc ! router eigrp 1 network

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-51 Example: LSC2 interface XTagATM21 ip unnumbered Loopback0 extended-port ATM1/0 bpx 2.1 tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 30 tag-switching atm cos standard 15 tag-switching atm cos available 5 ! interface XTagATM41 ip unnumbered Loopback0 extended-port ATM1/0 bpx 4.1 tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 30 tag-switching atm cos standard 15 tag-switching atm cos available 5 interface XTagATM261 ip unnumbered Loopback0 extended-port ATM1/0 bpx tag-switching ip tag-switching atm cos control 50 tag-switching atm cos premium 30 tag-switching atm cos standard 15 tag-switching atm cos available 5 ! Router eigrp 1 network

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-52 Summary Example: BPX2 bpx1 TN StrataCom BPX June :07 GMT Trunk: 1.2 Service Class Template ID: 1 This Command: cnfvsiif bpx1 TN StrataCom BPX June :07 GMT Trunk: 1.2 Service Class Template ID: 1 This Command: cnfvsiif cnfvsiif cnfvsiif cnfvsiif

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-53 Summary Classification is done by using IP TOS Scheduling in core is based on BPX standard QBIN servicing Drop policy based on WRED if configured, and always by base BPX scheduling algorithms in IP+ATM

© 1999, Cisco Systems, Inc. CMPLS 1.0—6-54 Blank for pagination