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QoS Deployment for Enterprise Networks

Learn how to design and implement a converged voice, video, and data network with quality of service (QoS) to guarantee voice quality, enable video conferencing, and support critical data applications.

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QoS Deployment for Enterprise Networks

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  1. Deploying QoS for Enterprise Network InfrastructuresMark MontañezEnterprise Solutions EngineeringDesign Team: CANI - QoS

  2. Session Objectives • To be able to design and implement a converged voice, video, and data network that can guarantee voice quality while enabling video conferencing and mission critical data applications • More information available here: • QoS SRND http://www.cisco.com/application/pdf/en/us/guest/netsol/ns17/c649/ccmigration_09186a00800d67ed.pdf • IP Tel SRND http://www.cisco.com/en/US/netsol/ns110/ns163/ns165/ns268/networking_solutions_design_guidances_list.html

  3. The Enterprise Network Design Model The OSI Stack Revisited Business Layer Application Layer Highly Available, QoS-Enabled Infrastructure Layer

  4. 3 Steps for Implementing QoS • Classification—Marking the packet with a specific priority denoting a requirement for special service from the network • Scheduling—Assigning packets to one of multiple queues (based on classification) for preferential treatment throughout the network • Provisioning—Accurately calculating the required bandwidth for all applications plus element overhead

  5. QoS Is Needed to Minimize Packet Loss, Delay and Delay Variation Where QoS Is Needed Central Campus Remote Branch WAN QoS—Campus Access QoS—Campus Dist. QoS—WAN QoS—Branch • Speed and duplex settings • Classification/trust on IP phone, VC station, content service, and Citrix server • Multiple queues on IP phone and access ports • Layer 3 policing for content distribution • Multiple queues on all ports; priority queuing for VoIP • WRED within data queues for congestion management • Low-latency queuing • Data traffic queue provisioning • Link fragmentation and interleave • Traffic shaping • Admission control • Speed and duplex settings • Classification/trust on IP phone, VC station, Content service and Citrix traffic • Multiple queues on IP phone and access ports

  6. Agenda • Quality Concerns with IP Telephony, Multimedia Applications and Mission-Critical Data • General Enterprise QoS Design Considerations • Connecting the End-Points • Designing the Campus • Enabling the WAN • QoS Impact • VoIP and the Telecommuter • Questions and Answers • Summary

  7. Example of PCM (64Kbps) IP Telephony Call 80Kbps 64Kbps Single PCM VoIP Call • Consistent, easily managed packet rate (default 50pps) • A G.711 call is really ~80Kbps over a data network • Packet loss • Current Cisco GW DSP CODEC algorithms can correct for 30 msec of lost voice—1 G.729A voice packet contains 20 msec of voice • One lost FAX over IP packet causes a MODEM retrain; 2 drops cause a call disconnect • Causes of packet loss: Network quality, network congestion and delay variation (jitter buffer under-runs and over-runs)

  8. Example of 384 Kbps Video (30 fps) Conferencing Traffic (CIF) “I” Frame 1024–1518 Bytes “I” Frame 1024–1518 Bytes 600Kbps 30pps “P” and “B” Frames 128–256 Bytes • “I” frame is a full sample of the video • “P” and “B” frames use quantization via motion vectors and prediction algorithms 15pps 32Kbps

  9. Video Conferencing Traffic Packet Size Breakdown (CIF) 65–128 Bytes 1% 1025–1500 Bytes 37% 129–256 Bytes 34% 513–1024 Bytes 20% 257–512 Bytes 8%

  10. Citrix DLSw+ PeopleSoft Oracle ERP—underlying apps PC replication/ multicast applications Video distribution FTP Batch updates Backups Napster KaZaa Morpheus Grokster Some Applications that Require QoS

  11. Provisioning for Data:General Principles • Profile applications to their basic network requirements • Don’t over-engineer provisioning • Use proactive policies before reactive (policing) policies • Seek executive endorsement of relative ranking of application priority prior to rolling out QoS policies for data

  12. Agenda • Quality Concerns with IP Telephony, Multimedia Applications and Mission-Critical Data • General Enterprise QoS Design Considerations • Connecting the End-points • Designing the Campus • Enabling the WAN • QoS Impact • VoIP and the Telecommuter • Questions and Answers • Summary

  13. Layer 2 and 3 Traffic Classification Layer 2802.1Q/p TAG4 Bytes PREAM. SFD DA SA Type PT DATA FCS Three Bits Used for CoS (802.1D User Priority) PRI CFI VLAN ID Layer 3IPV4 ToS1 Byte Version Length Len ID Offset TTL Proto FCS IP-SA IP-DA Data 7 6 5 4 3 2 1 0 Flow Control for DSCP IP Precedence DSCP Standard IPV4: Three MSB Called IP Precedence (Diffuser May Use Six D.S. Bits Plus Two for Flow Control)

  14. Diff-Serv Behaviors Per-Hop Behaviors (PHB) Diffuser Code Points (DSCP) Expedited Forwarding 101110 EF Assured Forwarding Low Drop Prêt Med Drop Prêt High Drop Prêt AF41 AF42 AF43 100010 100100 100110 Class Selector (CS) 4 011010 011100 011110 Class Selector (CS) 3 AF31 AF32 AF33 010010 010100 010110 AF21 AF22 AF23 Class Selector (CS) 2 AF11 AF12 AF13 001010 001100 001110 Class Selector (CS) 1 Best Effort 000000

  15. DSCP Decimal Binary IP PREC Binary <BE1 2 000010 0 000 4 <BE2 000100 0 000 6 <BE3 000110 0 000 BE 0 000000 0 000 10 AF11 001010 1 001 12 AF12 001100 1 001 AF13 14 001110 1 001 18 AF21 010010 2 010 AF22 20 010100 2 010 22 AF23 010110 2 010 26 AF31 011010 3 011 AF32 28 011100 3 011 AF33 30 011110 3 011 34 AF41 100010 4 100 AF42 36 100100 4 100 AF43 38 100110 4 100 46 EF 101110 5 101 Diff-Serv Behaviors Per-Hop Behaviors (PHB) Diffuser Code Points (DSCP) Expedited Forwarding 101110 EF Assured Forwarding Low Drop Prêt Med Drop Prêt High Drop Prêt AF41 AF42 AF43 100010 100100 100110 Class Selector (CS) 4 011010 011100 011110 Class Selector (CS) 3 AF31 AF32 AF33 010010 010100 010110 AF21 AF22 AF23 Class Selector (CS) 2 AF11 AF12 AF13 001010 001100 001110 Class Selector (CS) 1 Best Effort 000000

  16. Si Si Designing the Campus General Guidelines • A robust, modern switching design is a requirement Designing High-Performance Campus Intranets with Multilayer Switching http://www.cisco.com/warp/public/cc/so/cuso/epso/entdes/highd_wp.htm Gigabit Campus Design http://www.cisco.com/warp/public/cc/so/neso/lnso/cpso/camp_wp.htm Gigabit Campus Network Design— Principles and Architecture http://www.cisco.com/en/US/netsol/ns110/ns146/ns147/ns17/networking_solutions_implementation_white_paper09186a00800a3e16.shtml • Multiple queues are required on all interfaces to prevent TX queue congestions/drops • RTP bearer traffic should always go into the highest priority queue; control should go into separate queue

  17. Building the Branch Office General Guidelines • The WAN branch router must support advanced Cisco QoS tools • Map between layer 2 and layer 3 classification schemes • Use a branch switch with multiple queues • 802.1Q trunking between the router and switch for multiple VLAN support (separation of voice/data traffic) is preferred

  18. Enabling the WAN General Guidelines QoS Enabled WAN • Queuing • Use CBWFQ for data on all WAN interfaces in a converged network • LLQ for VoIP and video conferencing • Traffic shaping is required for all frame-relay and ATM/FR networks • If running VoIP, use LFI on WAN connections below 768Kbps • Don’t use LFI on any video over IP solutions with VoIP • Use cRTP carefully

  19. VoIP Over IPSec VPNs General Guidelines VPN • Crypto is a FIFO queue, so: • Take steps to not over drive the crypto engines capabilities (CAR, skip crypto for voice, new code coming, etc.) • Use pre-classify when more than ToS byte used for classification • If using IP mc MoH, IPSec GRE tunnel is required • cRTP does not work w/IPSec • See ESE SOHO VPN QoS Design Guide (Part of QoS SRND) • See ESE Web Site V3PN Design Guide (available through your SE)

  20. Agenda • Quality Concerns with IP Telephony, Multimedia Applications and Mission-Critical Data • General Enterprise QoS Design Considerations • Connecting the End-Points • Designing the Campus • Enabling the WAN • QoS Impact • VoIP and the Telecommuter • Questions and Answers • Summary

  21. Classification Tools: Trust Boundaries Endpoints Core Access Distribution WAN Agg. 1 • A device can be trusted if it correctly classifies packets • For scalability, classification should be done as close to the edge as possible • The outermost trusted devices represent the trust boundary • 1 and 2 are optimal, 3 is acceptable (if access switch cannot perform classification) 2 3 Trust Boundary 1 2 3

  22. PC CoS Settings Are Not Trusted IP Phone Switch ASIC Untrusted: Phone ASIC Will Re-Write CoS 0 COS = 5 COS = 5 COS = 7 COS = 0 • set port qos <mod/port> trust-ext _____ • Only applies to port trust on the IP phone PC Ethernet port • Un-related to actual cat6k port trust • set port qos <mod/port> trust ____ • Applies to the actual switch port trust rules • untrusted (default), trust-cos, trust-ipprec, trust-dscp • Some 6k 10/100 cards require an additional ACL to actually enable port trust

  23. Connecting the Video Conferencing Stations L3 Aware • Watch physical speed/duplex settings/negotiation • Trust classification of known room systems but filter on assigned IP address; VC station is in a conference room where anyone has access to the Ethernet port • Use H.323 proxy to classify traffic from PC-based VC for admission to WAN PQ • All video conferencing traffic should be set to DSCP AF41

  24. Integrating DLSw+ L3 Aware • Default is IP Precedence 5 with no configuration; can cause PQ over subscription if not accounted for • trust-ipprec from router generating DLSw+ traffic • Use the dlsw remote-peer priority to use the different DLSw+ ports; change the defaultDLSw+ IP Prec mapping • dlsw remote-peer 0 tcp 171.70.234.121 priority • dlsw tos map high 2 medium 2 normal 2 low 2 • DLSw+ is not DSCP aware so we can only set the IP Precedence; admission to mission critical class needs to take this into account • Place in bandwidth defined class-based weighted fair queue

  25. Agenda • Quality Concerns with IP Telephony, Multimedia Applications and Mission-Critical Data • General Enterprise QoS Design Considerations • Connecting the End-Points • Designing the Campus • Enabling the WAN • QoS Impact • VoIP and the Telecommuter • Questions and Answers • Summary

  26. Is QoS Needed in the Campus? “Just throw more bandwidth at it. That will solve the problem!” Transmit Buffer Management Is Just as Important as Bandwidth Management

  27. Transmit Queue Congestion—WAN 10/100m Queued 128k Uplink WAN Router • 100 meg in 128 kb/s out—packets serialize in faster than they can serialize out • Packets queued as they wait to serialize out slower link

  28. Transmit Queue Congestion—LAN 1 Gig Link Queued 100 Meg Link Distribution Switch Access Switch • 1 gig in 100 meg out—packets serialize in faster than they can serialize out • Packets queued as they wait to serialize out slower link • Many access ports aggregated into single distribution link; instantaneous periods of congestion

  29. Transmit Queue Congestion—The Answer Queue Mgr • Multiple queues allow us to protect the queue containing important traffic from drops • Drops happen in BE only queue(s) Queue 1 Queue 2 RR/WRR/PQ Queue Scheduler Round Robin, Weighted Round Robin or Priority Queuing Used for Scheduling between Queues Data Voice

  30. Queue Mgr Queue 1 Queue 2 Data Voice RR/WRR/PQ Queue Scheduler Transmit Queue Visibility • Cat 6k CatOS - show qos statistics 4/1 • Cat 4500 SupIV - show int fa3/2 count all • Cat 3550 – show mls qos int statistics fa3/2

  31. Queue Mgr Queue 1 Queue 2 Data Voice RR/WRR/PQ Queue Scheduler Transmit Queue—Visibility 4500 SUPIV 4006-SUPIII-Access#sh int g3/2 count all . . . Port InPkts 1549-9216 OutPkts 1549-9216 Port InPkts 1549-9216 OutPkts 1549-9216 Gi3/2 0 0 Port Tx-Bytes-Queue-1 Tx-Bytes-Queue-2 Tx-Bytes-Queue-3 Tx-Bytes-Queue-4 Gi3/2 0 0 0 0 Port Tx-Drops-Queue-1 Tx-Drops-Queue-2 Tx-Drops-Queue-3 Tx-Drops-Queue-4 Gi3/2 1122 0 0 0 Port Rx-No-Pkt-Buff RxPauseFrames TxPauseFrames PauseFramesDrop Gi3/2 0 0 0 0

  32. Access Layer Classification and Scheduling Required towards Phone and Distribution Layer Core QoS Required Distribution Access

  33. Access 2900/3500—2Q1T 2950 4Q (priority schedule or WRR) 3550—1P3Q2T or 4Q2T 4000/SUPII—2Q1T 4500/SUPIV—1P3Q2T (priority config) 6500—2Q2T TX(10/100 classic) 1Q4T RX(10/100 classic) 1P2Q2T TX (gig classic) 1P1Q4T RX (gig classic) Distribution/core 4500/SUPIV—1P3Q2T 6500—2Q2T TX(10/100 classic) 1Q4T RX(10/100 classic) 1P2Q2T TX (gig classic) 1P1Q4T RX (gig classic) 1P3Q1T TX (10/100 fabric) 1P1Q RX (10/100 fabric) 1P2Q1T TX (gig fabric) 1P1Q8T RX (gig fabric) Campus QoS Catalyst Switches which Support Multiple Queues Queuing/Scheduling Capabilities Depend on Hardware:

  34. Campus QoS Catalyst Switches which Support Multiple Queues Queuing/Scheduling Capabilities Depend on Hardware: • 1P2Q2T • 1P2Q2T—One priority queue • 1P2Q2T—Two additional queues • 1P2Q2T—Two drop thresholds for each queue • 2Q2T • 2Q2T—Two queues • 2Q2T—Two drop thresholds for each queue

  35. 6500 6500 QoS in Catalyst 3550 • 4 transmit queues (1P3Q2T or 4Q2T) • Need to configure PQ and insure that CoS 5 traffic serviced via PQ • Configurable PQ for 4th queue • priority-queue out • Configurable CoS to specific queue • wwr-queue 4 5 • Configurable queue depth (expert mode) • Configurable queue weight (expert mode) • 802.1p, DSCP or ACL-based QoS • Trust DSCP, or CoS (policy maps) • Can set DSCP or CoS by port (marked/rewriteor unmarked) • Mapping from CoS to DSCP/DSCP to CoS • Now shipping with inline power 3550 3550 3550

  36. 6500 6500 Catalyst 3550 Example Access Layer—Access Port and Uplink mls qos map cos-dscp 0 10 18 26 34 46 48 56 mls qos ! ! interface GigabitEthernet0/12 description Uplink to Distribution no ip address flowcontrol send off mls qos trust dscp wrr-queue cos-map 4 5 priority-queue out ! interface Fastthernet0/1 description to IP Phone no ip address mls qos trust CoS wrr-queue cos-map 4 5 priority-queue out switchport voice vlan 111 switchport access vlan 11 switchport priority extend cos 0 3550 3550 3550

  37. 6500 6500 Catalyst 3550 Example Access Layer—Classification mls qos map cos-dscp 0 10 18 26 34 46 48 56 mls qos ! class-map match-all VoIP-Bearer match access-group name VoIP-Bearer class-map match-all Mission-Critical match access-group name Mission-Critical class-map match-all VoIP-Control match access-group name VoIP-Control ! policy-map VoIP-Policy class VoIP-Control set ip dscp 26 class VoIP-Bearer set ip dscp 46 class Mission-Critical set ip dscp 18 ! interface GigabitEthernet0/1 description Classification no ip address flowcontrol send off service-policy in VoIP-Policy wrr-queue cos-map 4 5 priority-queue out 3550 3550 3550

  38. QoS in Catalyst 4500—Access (SUPIV) • 4 queues (1P3Q2T or 4Q2T) • Need to configure PQ and insure that CoS 5 traffic serviced via PQ • Configurable PQ for 3rd queue • tx-queue 3 • Priority high • Configurable queue depth (expert mode) • Configurable queue weight (expert mode) • 802.1p, DSCP or ACL-based QoS (policy maps) • Can set DSCP or CoS by port (marked/rewrite or unmarked) • Trust DSCP or CoS • Mapping from CoS to DSCP/DSCP to CoS • 4500 shipping with inline power (no PEM) 4000SUPIII

  39. Catalyst 4000 (SUPIII) Example Access Layer—Access Port and Uplink qos map cos 1 to dscp 10 qos map cos 2 to dscp 18 qos map cos 3 to dscp 26 qos map cos 4 to dscp 34 qos map cos 5 to dscp 46 qos ! ! interface GigabitEthernet1/1 description Uplink to Distribution qos trust dscp no snmp trap link-status tx-queue 3 priority high ! ! interface FastEthernet4/1 description To IP Phone qos trust cos no snmp trap link-status switchport voice vlan 111 switchport vlan 11 switchport priority extend cos 0 tx-queue 3 priority high Core Distribution Access 4000

  40. Catalyst 4000 (SUPIII) Example Access Layer—Classification qos map cos 1 to dscp 10 qos map cos 2 to dscp 18 qos map cos 3 to dscp 26 qos map cos 4 to dscp 34 qos map cos 5 to dscp 46 qos ! class-map match-all VoIP-Bearer match access-group name VoIP-Bearer class-map match-all Mission-Critical match access-group name Mission-Critical class-map match-all VoIP-Control match access-group name VoIP-Control ! policy-map VoIP-Policy class Mission-Critical set ip dscp 18 class VoIP-Control set ip dscp 26 class VoIP-Bearer set ip dscp 46 ! interface GigabitEthernet1/1 qos trust cos service-policy in VoIP-Policy tx-queue 3 priority high Core Distribution Access 4000

  41. QoS in 6500 Switches—Access (PFC) • Redundant SUP’s, transmit and receive queues, priority queues and multiple drop thresholds • 802.1p, DSCP or ACL-based QoS (policy maps) • Trust DSCP or CoS • Can set by port DSCP or CoS (marked/rewrite or unmarked) • Mapping from CoS to DSCP/DSCP to CoS • Port can trust DSCP, IP Prec or CoS • Recommended: trust-cos (access to RX PQ) • 10/100 cards require an additional step of configuring ACL to trust traffic • Output scheduling consists of: • Assigning traffic to queues based on CoS • Configuring threshold levels • Modifying buffer sizes (expert mode) • Assigning weights for WRR (expert mode) 6500

  42. Catalyst 6500 Example Access Layer—Catalyst 6000 cat6k-access> (enable) set qos enable cat6k-access> (enable) set qos cos-dscp-map 0 10 18 26 34 46 48 56 cat6k-access> (enable) set qos ipprec-dscp-map 0 10 18 26 34 46 48 56 cat6k-access> (enable) set qos map 1p2q2t tx 2 1 cos 3 cat6k-access> (enable) set qos map 2q2t tx 2 1 cos 3 cat6k-access> (enable) set port qos 5/1-48 trust trust-cos cat6k-access> (enable) set port qos 5/1-48 cos-ext 0 cat6k-access> (enable) set port qos 5/1-48 vlan-based cat6k-access> (enable) set qos acl ip ACL_IP-PHONES trust-cos ip any any cat6k-access> (enable) commit qos acl all cat6k-access> (enable) set qos acl map ACL_IP-PHONES 110 cat6k-access> (enable) set port qos 1/1-2 trust trust-cos Access 4000

  43. Distribution Layer Classification and Scheduling Required to/from Access Layer Core QoS Required Distribution Access

  44. QoS in Catalyst 4500—Distribution (SUPIV) • 4 queues (1P3Q2T or 4Q2T) • Need to configure PQ and insure that CoS 5 traffic serviced via PQ • Configurable PQ for 3th queue • tx-queue 3 • Priority high • Configurable queue depth (expert mode) • Configurable queue weight (expert mode) • 802.1p, DSCP or ACL-based QoS (policy maps) • Trust DSCP or CoS • Can set by port DSCP or CoS (marked/rewrite or unmarked) • Mapping from CoS to DSCP/DSCP to CoS • Careful w/over-subscribed cards—32g max 4006w/SUPIII

  45. Catalyst 4500 (SUPIV) Example Distribution Layer—Downlink Core qos map cos 1 to dscp 10 qos map cos 2 to dscp 18 qos map cos 3 to dscp 26 qos map cos 4 to dscp 34 qos map cos 5 to dscp 46 qos ! interface GigabitEthernet4/1 qos trust cos no snmp trap link-status tx-queue 3 priority high ! interface GigabitEthernet4/2 qos trust dscp no snmp trap link-status tx-queue 3 priority high Distribution Access 4000

  46. QoS in 6500—Distribution • Redundant sups, transmit and receive queues, priority queues and multiple drop thresholds • CoS, DSCP or ACL-based QoS (policy maps) • Trust DSCP or CoS • Can set by port DSCP or CoS (marked/rewrite or unmarked) • Mapping from CoS to DSCP/DSCP to CoS • Port can trust DSCP, IP Prec or CoS • Recommended: trust-cos (access to RX PQ) • 10/100 cards require an additional step of configuring ACL to trust traffic • Output scheduling consists of: • Assigning traffic to queues based on CoS • Configuring threshold levels • Modifying buffer sizes (expert mode) • Assigning weights for WRR (expert mode) 6500

  47. Catalyst 6500 Example—Hybrid Distribution Layer—Catalyst 6000 Hybrid 6500 cat6k-distrib> (enable) set qos enable cat6k-distrib> (enable) set qos ipprec-dscp-map 0 10 18 26 34 46 48 56 cat6k-distrib> (enable) set qos cos-dscp-map 0 10 18 26 34 46 48 56 cat6k-distrib> (enable) set qos map 1p2q2t tx queue 2 1 cos 3 cat6k-distrib> (enable) set qos map 2q2t tx queue 2 1 cos 3 cat6k-distrib> (enable) set port qos 1/1-2 trust trust-cos cat6k-distrib> (enable) set port qos 3/2 trust trust-dscp cat6k-distrib> (enable) set port qos 9/1 trust trust-dscp cat6k-distrib> (enable) set port qos 9/1 port-based cat6k-distrib> (enable) set qos acl ip ACL_TRUST-WAN trust-dscp ip any any cat6k-distrib> (enable) commit qos acl ACL_TRUST-WAN cat6k-distrib> (enable) set qos acl map ACL_TRUST-WAN 9/1

  48. Catalyst 6500 Example—Native Distribution Layer—Catalyst 6000 Native-IOS 6500 mls qos mls qos map ip-prec-dscp 0 10 18 26 34 46 48 56 mls qos map cos-dscp 0 10 18 26 34 46 48 56 int range gigabitEthernet 1/1 - 2 wrr-queue cos-map 2 1 3 wrr-queue cos-map 2 2 4 ! Trust DSCP from the Layer-3 aware enabled Access Switch interface GigabitEthernet2/1 description trunk port to PFC enabled cat6k-access no ip address wrr-queue cos-map 2 1 3 wrr-queue cos-map 2 2 4 mls qos vlan-based mls qos trust dscp switchport switchport trunk encapsulation dot1q switchport mode trunk

  49. Catalyst 6500 Example—Native (Cont.) Distribution Layer—Catalyst 6000 ! Trust CoS from the Layer 2 only Catalyst 4000 Access Switch interface GigabitEthernet2/2 description trunk port to layer 2-only cat4k no ip address wrr-queue cos-map 2 1 3 wrr-queue cos-map 2 2 4 mls qos vlan-based mls qos trust cos switchport switchport trunk encapsulation dot1q switchport mode trunk ! Trust CoS from the Layer 2 only 3500 Access Switch interface GigabitEthernet3/1 description trunk port to layer 2-only 3500 no ip address wrr-queue cos-map 2 1 3 wrr-queue cos-map 2 2 4 mls qos vlan-based mls qos trust cos switchport switchport trunk encapsulation dot1q switchport mode trunk Native-IOS 6500

  50. Is QoS Needed in the Campus? “Buffer management is as important as bandwidth management…” Just Throw Bandwidth at It…NOT!

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