QoS on the Satellite System
AutoQoS which automates consistent deployment of QoS features is enabled on the satellite system. All the user-configured Layer2 and Layer3 QoS features are applied on the ASR9000 and no separate Qos configuration required for the satellite system. Auto-Qos handles the over-subscription of the ICL links. All other QoS features, including broadband QoS, on regular ports are supported on satellite ports as well. System congestion handling between the ASR9000 Series Router and satellite ports is setup to maintain priority and protection. AutoQoS Provide sufficient differentiation between different classes of traffic that flow on the satellite ICLs between the ASR9000 Series Router and the Satellite .
The system can support up to 14 unique shape rates for 1G port shapers. 1G ports are represented using a L0 entity in the Traffic Manager (TM) hierarchy. Port shapers are applied at this level. When speed changes on satellite ports, QOS EA would automatically reconfigure any policy-maps based on underlying satellite ports speed. However if there are no policies, then the Policy Manager (PM) needs to setup the speed of the port by calling the port-shaper API (Application Programming Interface). The system shall modify any policies which are percentage-based when the underlying ports speed changes due to AN. There would be a timelag for the Autonegotiated speed to be propagated to the policies on the ASR9000 series router and during that time, packet drops are expected in the satellite device.
For more information about QoS for the satellite system, refer the Modular QoS Configuration Guide for Cisco ASR 9000 Series Routers.
Limitations
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Queueing on an ingress service-policy is not supported on satellite interfaces.
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Only flat and 2-level HQoS policies are supported on satellite interfaces in L2 Fabric and simple ring topologies.
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The burst size can be set to a wide range of sizes up to 2000 ms. However, for satellite ports, the actual burst size when queuing (shaping) is used is always set to 500 usec of 1Gbits or less. This is because of constraints in the hardware.
Auto QoS
Traffic from the Satellite nV system to the Cisco ASR 9000 series router and traffic from the Cisco ASR 9000 series router to the Satellite nV system have been discussed.
Satellite to Cisco ASR 9000 Series Router
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Traffic is handled using the trusted port model.
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Automatic packet classification rules determine whether a packet is control packet (LACP, STP, CDP, CFM, ARP, OSPF etc), high priority data (VLAN COS 5,6,7, IP prec 5, 6, 7) or normal priority data and queued accordingly.
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Cisco NCS 5000 Series satellite does not classify further into LACP, OAM, BFD and so on as on earlier satellites.
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All user-configured Layer 2 and Layer 3 features(including QoS) are applied on the Cisco ASR 9000 Series Host and not on the satellite.
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Protocol types auto-prioritized by the satellite - all IEEE control protocols (01 80 C2 xx xx xx), LACP, 802.3ah, CFM, STP, CDP, LLDP, ARP, OSPF, BFD, RIP, BGP, IGMP, RSVP, HSRP, VRRP p2 q.
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Cisco NCS 5000 Series satellite does not auto prioritize the protocols mentioned above.
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User data packets auto-prioritized by the satellite - VLAN COS 5, 6, 7, IP precedence 5, 6, 7 MPLS EXP 5, 6, 7. MPLS EXP is not classified in the case of Cisco NCS 5000 series satellite.
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Cisco NCS 5000 Series devices used as nV satellite |
Cisco ASR 9000 Series Router to Satellite
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Traffic targeted to a satellite egress port is shaped on Cisco ASR 9000 to match downstream access port speed.
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There is no need for further QoS on the satellite itself, since Cisco ASR 9000 QoS is sufficient and provides necessary deep buffering normally not available on Cisco ASR 9000v satellite device with its 4 MB buffers or Cisco NCS 5000 Series standalone device with its 16 MB buffers.
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Traffic is streamed based on the full 3-level egress queuing hierarchy.
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Each remotely managed satellite access GigE port is auto-shaped to match access line speed.
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Satellite protocols going over ICL default queues get highest scheduling priority while full 3 level MQC hierarchy is supported on the egress satellite ports.
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The above connections are also applicable to the Cisco NCS 5000 Series devices used as nV satellite. |