8. Advanced Queuing Topics

  1. Miguel Barreiros1 and
  2. Peter Lundqvist2

Published Online: 20 DEC 2010

DOI: 10.1002/9780470976814.ch8

QOS-Enabled Networks: Tools and Foundations

QOS-Enabled Networks: Tools and Foundations

How to Cite

Barreiros, M. and Lundqvist, P. (2011) Advanced Queuing Topics, in QOS-Enabled Networks: Tools and Foundations, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470976814.ch8

Author Information

  1. 1

    Juniper Networks, Portugal

  2. 2

    Juniper Networks, Sweden

Publication History

  1. Published Online: 20 DEC 2010
  2. Published Print: 7 JAN 2011

ISBN Information

Print ISBN: 9780470686973

Online ISBN: 9780470976814



  • advanced queuing topics, debate about optimal size of queues - different memory allocation techniques;
  • advanced scenarios, over-provisioning and guaranteed rates - in large-scale queues to differentiate shaping rates;
  • modern QOS scenarios and implementations - multiple levels of scheduling and shaping;
  • Broadband Service Router (BSR),10-Gbps Gigabit Ethernet link to switch - two connections between switch and two DSLAM switches, being both Gigabit Ethernet links;
  • subscribers, traffic contracts with different services and rates - traffic from subscribers, shaped to align with service contract;
  • next layer of shaping, occurring on VLANs - existing within each S-VLAN;
  • QOS scheduling on a large scale, units and schedulers - propagating important traffic;
  • memory allocation dynamic (MAD) - logic of implementing MAD, simple, but actually relatively complex;
  • TCP protocols, concept of rate optimization windows - as congestion windows and receiving windows;
  • differentiating traffic inside a queue with WRED - traffic types, sharing same queue, necessary to differentiate between them


This chapter contains sections titled:

  • Hierarchical Scheduling

  • Queues Lengths and Buffer Size

  • Dynamically Sized versus Fixed-Size Queue Buffers

  • RED – Random Early Discard

  • Using RED with TCP Sessions

  • Differentiating Traffic Inside a Queue with WRED

  • Head versus Tail RED

  • Segmented and Interpolated RED Profiles

  • Conclusion

  • Further Reading