Scheduling with dynamic bandwidth allocation for DiffServ classes

The diverse service requirements of emerging Internet applications faster the need for flexible and scalable IP quality-of-service (QoS) schemes. Due to its simplicity and scalability, DiffServ is expected to be widely deployed across the Internet. Though DiffServ supporting scheduling algorithms for output-queueing (OQ) switches have been widely studied, there are few DiffServ scheduling algorithms for input-queueing (IQ) switches. In this paper, we propose the dynamic DiffServ scheduling (DDS) algorithm for IQ switches to provide dynamic bandwidth allocation for DiffServ classes. The basic idea of DDS is to schedule EF and AF traffic according to their minimum service rates with the reserved bandwidth and schedule AF and BE traffic fairly with the excess bandwidth. We evaluate the performance of DDS under bursty traffic arrivals and compare it with PQWRR, an existing scheduling algorithm suitable for supporting DiffServ for OQ switches. Simulations results show that DDS provides minimum bandwidth guarantees for EF and AF traffic and fair bandwidth allocation for BE traffic. DDS also achieves the delay and jitter performance for EF traffic close to that of PQWRR and the delay performance for AF traffic better than that of PQWRR at high loads. Using comparator-tree based arbitration components, it is feasible to implement DDS in hardware at high speed.

[1]  Brian E. Carpenter,et al.  Differentiated services in the Internet , 2002, Proc. IEEE.

[2]  Iakovos S. Venieris,et al.  Efficient buffer management and scheduling in a combined IntServ and DiffServ architecture: a performance study , 1999, 1999 2nd International Conference on ATM. ICATM'99 (Cat. No.99EX284).

[3]  Mansoor Alam,et al.  Two scheduling algorithms for input-queued switches guaranteeing voice QoS , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[4]  Melody Moh,et al.  PQWRR scheduling algorithm in supporting of DiffServ , 2001, ICC 2001. IEEE International Conference on Communications. Conference Record (Cat. No.01CH37240).

[5]  Andrea Francini,et al.  A distributed scheduling architecture for scalable packet switches , 2000, IEEE Journal on Selected Areas in Communications.

[6]  Chun-Xiang Chen,et al.  An adaptive scheduler to provide QoS guarantees in an input-buffered switch , 2002, 2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333).

[7]  Van Jacobson,et al.  Link-sharing and resource management models for packet networks , 1995, TNET.

[8]  Zheng Wang,et al.  An Architecture for Differentiated Services , 1998, RFC.

[9]  Rainer Schoenen,et al.  Prioritized arbitration for input-queued switches with 100% throughput , 1999, IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462).

[10]  Scott Shenker,et al.  Integrated Services in the Internet Architecture : an Overview Status of this Memo , 1994 .

[11]  Nick McKeown,et al.  Scheduling algorithms for input-queued cell switches , 1996 .

[12]  David L. Black,et al.  An Architecture for Differentiated Service , 1998 .

[13]  Nick McKeown,et al.  The iSLIP scheduling algorithm for input-queued switches , 1999, TNET.

[14]  Fred Baker,et al.  Assured Forwarding PHB Group , 1999, RFC.

[15]  Nirwan Ansari,et al.  Provisioning QoS features for input-queued ATM switches , 1998 .

[16]  Kai-Yeung Siu,et al.  Linear-complexity algorithms for QoS support in input-queued switches with no speedup , 1999, IEEE J. Sel. Areas Commun..