11,778 research outputs found
Internet routing paths stability model and relation to forwarding paths
Analysis of real datasets to characterize the local stability properties of the Internet routing paths suggests that extending the route selection criteria to account for such property would not increase the routing path length. Nevertheless, even if selecting a more stable routing path could be considered as valuable from a routing perspective, it does not necessarily imply that the associated forwarding path would be more stable. Hence, if the dynamics of the Internet routing and forwarding system show different properties, then one can not straightforwardly derive the one from the other. If this assumption is verified, then the relationship between the stability of the forwarding path (followed by the traffic) and the corresponding routing path as selected by the path-vector routing algorithm requires further characterization. For this purpose, we locally relate, i.e., at the router level, the stability properties of routing path with the corresponding forwarding path. The proposed stability model and measurement results verify this assumption and show that, although the main cause of instability results from the forwarding plane, a second order effect relates forwarding and routing path instability events. This observation provides the first indication that differential stability can safely be taken into account as part of the route selection process
Stabilizing Inter-Domain Routing in the Internet
This paper reports the first self-stabilizing Border Gateway Protocol (BGP). BGP is the standard inter-domain routing protocol in the Internet. Self-stabilization is a technique to tolerate arbitrary transient faults.
The routing instability in the Internet can occur due to errors in configuring the routing data structures, the routing policies, transient physical and data link problems, software bugs, and memory corruption. This instability can increase the network latency, slow down the convergence of the routing data structures, and can also cause the partitioning of networks. Most of the previous studies concentrated on routing policies to achieve the convergence of BGP while the oscillations due to transient faults were ignored.
The purpose of self-stabilizing BGP is to solve the routing instability problem when this instability results from transient failures. The selfstabilizing BGP presented here provides a way to detect and automatically recover from this type of faults. Our protocol is combined with an existing protocol to make it resilient to policy conflicts as well
Study of BGP Convergence Time
Border Gateway Protocol (BGP), a path vector routing protocol, is a widespread exterior gateway protocol (EGP) in the internet. Extensive deployment of the new technologies in internet, protocols need to have continuous improvements in its behavior and operations. New routing technologies conserve a top level of service availability. Hence, due to topological changes, BGP needs to achieve a fast network convergence. Now a days size of the network growing very rapidly. To maintain the high scalability in the network BGP needs to avoid instability. The instability and failures may cause the network into an unstable state, which significantly increases the network convergence time. This paper summarizes the various approaches like BGP policies, instability, and fault detection etc. to improve the convergence time of BGP
Cascaded multiplexed optical link on a telecommunication network for frequency dissemination
We demonstrate a cascaded optical link for ultrastable frequency
dissemination comprised of two compensated links of 150 km and a repeater
station. Each link includes 114 km of Internet fiber simultaneously carrying
data traffic through a dense wavelength division multiplexing technology, and
passes through two routing centers of the telecommunication network. The
optical reference signal is inserted in and extracted from the communication
network using bidirectional optical add-drop multiplexers. The repeater station
operates autonomously ensuring noise compensation on the two links and the
ultra-stable signal optical regeneration. The compensated link shows a
fractional frequency instability of 3 \times 10-15 at one second measurement
time and 5 \times 10-20 at 20 hours. This work paves the way to a wide
dissemination of ultra-stable optical clock signals between distant
laboratories via the Internet network
Fast emergency paths schema to overcome transient link failures in ospf routing
A reliable network infrastructure must be able to sustain traffic flows, even
when a failure occurs and changes the network topology. During the occurrence
of a failure, routing protocols, like OSPF, take from hundreds of milliseconds
to various seconds in order to converge. During this convergence period,
packets might traverse a longer path or even a loop. An even worse transient
behaviour is that packets are dropped even though destinations are reachable.
In this context, this paper describes a proactive fast rerouting approach,
named Fast Emergency Paths Schema (FEP-S), to overcome problems originating
from transient link failures in OSPF routing. Extensive experiments were done
using several network topologies with different dimensionality degrees. Results
show that the recovery paths, obtained by FEPS, are shorter than those from
other rerouting approaches and can improve the network reliability by reducing
the packet loss rate during the routing protocols convergence caused by a
failure.Comment: 18 page
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