Program at a glance Tutorial program Technical program Abstracts Papers
- Routing Stability and Convergence
- Full Paper
- Routing Stability in Congested Networks: Experimentation and Analysis
Aman Shaikh (University of California, Santa Cruz)
Lampros Kalampoukas (Bell Labs, Lucent Technologies)
Rohit Dube (Bell Labs, Lucent Technologies)
Anujan Varma (University of California, Santa Cruz)
Loss of the routing protocol messages due to network congestion
can cause peering session failures in routers, leading to
route flapping 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.
We subsequently 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 queuing and propagation delays
adversely affect BGP's resillience 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 scheduling and buffer management
policies in the routers, to achieve stable and robust network operation.