Routing stability in congested networks: experimentation and analysis

Loss of the routing protocol messages due to network congestion can cause peering session failures in routers, leading to route flaps and routing instabilities. We study the effects of traffic overload on routing protocols by quantifying the stability and robustness properties of two common Internet routing protocols, OSPF and BGP, when the routing control traffic is not isolated from data traffic. We develop analytical models to quantify the effect of congestion on the robustness of OSPF and BGP as a function of the traffic overload factor, queueing delays, and packet sizes. We perform extensive measurements in an experimental network of routers to validate the analytical results. Subsequently we use the analytical framework to investigate the effect of factors that are difficult to incorporate into an experimental setup, such as a wide range of link propagation delays and packet dropping policies. Our results show that increased queueing and propagation delays adversely affect BGP's resilience to congestion, in spite of its use of a reliable transport protocol. Our findings demonstrate the importance of selective treatment of routing protocol messages from other traffic, by using scheduling and utilizing buffer management policies in the routers, to achieve stable and robust network operation.

[1]  Roe Goodman,et al.  Introduction to stochastic models , 1987 .

[2]  Yakov Rekhter,et al.  A Border Gateway Protocol 4 (BGP-4) , 1994, RFC.

[3]  T. V. Lakshman,et al.  Beyond best effort: router architectures for the differentiated services of tomorrow's Internet , 1998, IEEE Commun. Mag..

[4]  Stefan Savage,et al.  The end-to-end effects of Internet path selection , 1999, SIGCOMM '99.

[5]  Vern Paxson,et al.  End-to-end routing behavior in the Internet , 1996, TNET.

[6]  John Moy,et al.  OSPF Version 2 , 1998, RFC.

[7]  Deborah Estrin,et al.  Persistent route oscillations in inter-domain routing , 2000, Comput. Networks.

[8]  W. Richard Stevens,et al.  TCP/IP Illustrated, Volume 2: The Implementation , 1995 .

[9]  Farnam Jahanian,et al.  Experimental study of Internet stability and backbone failures , 1999, Digest of Papers. Twenty-Ninth Annual International Symposium on Fault-Tolerant Computing (Cat. No.99CB36352).

[10]  Van Jacobson,et al.  The synchronization of periodic routing messages , 1994, TNET.

[11]  Ramesh Govindan,et al.  An architecture for stable, analyzable Internet routing , 1999, IEEE Netw..

[12]  Bilal Chinoy.  Dynamics of internet routing information , 1993, SIGCOMM 1993.

[13]  Bassam Halabi,et al.  Internet Routing Architectures , 1997 .

[14]  J. Moy,et al.  OSPF: Anatomy of an Internet Routing Protocol , 1998 .

[15]  Ramesh Govindan,et al.  An analysis of Internet inter-domain topology and route stability , 1997, Proceedings of INFOCOM '97.

[16]  Farnam Jahanian,et al.  Internet routing instability , 1997, SIGCOMM '97.

[17]  Gordon T. Wilfong,et al.  An analysis of BGP convergence properties , 1999, SIGCOMM '99.

[18]  Farnam Jahanian,et al.  Origins of Internet routing instability , 1999, IEEE INFOCOM '99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Societies. The Future is Now (Cat. No.99CH36320).

[19]  Joel M. Halpern,et al.  Classical IP and ARP over ATM , 1998, RFC.