Category Archives: QoS

Performance Routing (PfR)

Phases wheel:

  1. Profile/Learning Phase – learn flows with high latency and throughput = monitored traffic classes (MTC).
  2. Measure Phase – Collect and compute performance metrics for MTC.
  3. Apply Policy Phase – create low and high thresholds defining in-policy and out-of-policy (OOP) categories.
  4. Control Phase – influence by manipulating routing or PBR.
  5. Verify Phase – verify OOP event to make adjustmets to bring back in-policy.

Inrefaces types:

  1. Internal – connect to the internal network with Master Controller
  2. External – used to transmit packets out of the local network. Interfaces that monitored. At least 2.
  3. Local – used in the formation of the control plane mechanism. Source to communicate with Master Controller.

Operational Roles

Mandatory authentication – key-chains!

Master Controller (MC) and Border router (BR).

A single MC can support up to ten individual border routers
or up to 20 managed exit interfaces (external interfaces).

 

Passive monitoring: Measuring the performance metrics of interesting prefixes while the traffic is flowing through the device using NetFlow technology

Active monitoring: Creating a stream of synthetic traffic replicating the interesting traffic classes as closely as possible to measure the performance metrics of the synthetic traffic; uses Cisco integrated IP SLAs technology

Both active and passive monitoring: Combining both active and passive monitoring to generate a more complete picture of traffic flows within the network

QoS order of operations

Inbound
1. QoS Policy Propagation through Border Gateway Protocol (BGP) (QPPB)
2. Input common classification
3. Input ACLs
4. Input marking (class-based marking or Committed Access Rate (CAR))
5. Input policing (through a class-based policer or CAR)
6. IP Security (IPSec)
7. Cisco Express Forwarding (CEF) or Fast Switching

Outbound
1. CEF or Fast Switching
2. Output common classification
3. Output ACLs
4. Output marking
5. Output policing (through a class-based policer or CAR)
6. Queueing (Class-Based Weighted Fair Queueing (CBWFQ) and Low Latency Queueing (LLQ)), and Weighted Random Early Detection (WRED)