CCIE R&S QoS notes

Legacy custom queueing:

  • queue-list 1 [options]
  • custom-queue-list [x]
  • Can use ACLs to match traffic in queue list
  • Can be attached to an interface or frame-relay map-class

Legacy priority queueing:

  • priority-list 1 [options]
  • priority-group 1
  • Can use ACLs as above
  • Can be attached to an interface or frame-relay map-class

Legacy RED:

  • configured directly under the interface
  • uses FIFO, so can’t use RED and priority/custom queueing at the same time

Serial compression:

  • Compression you can use will depend on the encapsulation of the link.
  • PPP and HDLC use compression under the interface as these are point-to-pint
  • Frame-relay’s compression is configured under the frame-relay map command. This allows different compression types to different DLCIs

TCP/RTP header compression:

  • You need 2 connections for each session. So 8 sessions needs 16 connections
  • Both types of compression can be called in an MQC policy

Legacy generic traffic shaping:

  • interface x/x
  • traffic-shape group [acl] [settings]

CAR limiting:

  • Can use regular or special mac/ip prec/mpls exp ACLs
  • If using special ACL, must specify rate-limit option and can only contain a SINGLE line

MQC:

  • You can match on a lot of things, including the DLCI

Frame-relay fragmentation:

  • Can only do fragmentation on an interface or in a map-class

GRE:

  • Use QoS pre-classify on the tunnel interface in order to be able to do QoS on the inner markings

RSVP:

  • For the most part, ip rsvp bandwidth is the only command you need under the interface
  • Can still use MQC and tell classes to use remaining unreserved percents of bandwidth

3560 aggregate policer:

  • mls qos aggregate-policer [name] [bps] [burst] exceed-action drop
  • policy-map [name]
  • class [name]
  • police aggregate [name]
  • etc

3560 srr-queue:

  • srr-queue bandwidth shape uses 1/x as the calculation
  • srr-queue bandwidth share uses weights as the calculation
  • Both of the above are based on the physical speed of the interface. So take note if you’re limiting via srr-queue bandwidth limit
  • srr-queue bandwidth limit is an outbound limiter. To limit inbound you need to police
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2 thoughts on “CCIE R&S QoS notes”

  1. Hi Darren,

    I just stumbled on your blog on my Google search for legacy QoS and saw your countdown timer. Good luck! You can do it!

    Susan

  2. Hi Darren,
    can you please explain this part
    Both of the above are based on the physical speed of the interface. So take note if you’re limiting via srr-queue bandwidth limit
    Does this mean that shaping/sharing calculations will be based on the speed and not the srr-queue limit?

    Thanks

    Mena

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