CCIE R&S QoS notes

On March 18, 2012, in CCIE, by Darren

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 Responses to “CCIE R&S QoS notes”

  1. Susan says:

    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. mena says:

    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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