Thu, 06/09/2011 - 10:10 by Olivier Bonaventure • Categories:
Mon, 05/30/2011 - 15:57 by Laurent Vanbever • Categories:
Network-wide migrations of a running network, such as the replacement of a routing protocol or the modification of its configuration, can improve the scalability, manageability, security or the performances of the entire network. However, such migrations are an important source of concerns for network operators as the reconfiguration campaign can lead to long and service-affecting outages. In this work, we propose several techniques to address the problem of seamlessly (i.e. without loosing IP packets) modifying the configuration of commonly used routing-protocols.
Tue, 03/22/2011 - 15:18 by Olivier Bonaventure • Categories:
In an interesting survey presented at MPLS 2010, Cariden, a vendor of provisioning and traffic engineering tools, describes the current deployments of MPLS. The survey mentions several interesting results :
- the three major MPLS vendors are Cisco, Juniper and Alcatel Lucent, more than 15% of the networks are multivendor
- 57% of the networks uses IS-IS, the others use OSPF
Fri, 03/11/2011 - 01:36 by Olivier Bonaventure • Categories:
Recent browser have added an optimisation that enables the browser to resolve all the DNS names that appear inside a visited HTML page while the browser displays the HTML page. This can speed up the retrieval of the next link on which the user will click. Unfortunately, on websites that contain a large number of different hostnames on each page (e.g. pointers to homepages of users who have posted comments), this may lead to a large number of DNS requests for each HTML page retrieved.
Thu, 03/10/2011 - 23:32 by Olivier Bonaventure • Categories:
One of the problems faced by BGP routers today is the BGP churn, i.e. the number of messages that they have to process. Measurement studies have shown that a small fraction of the prefixes are responsible for a large fraction of the BGP messages that are received by BGP routers. Furthermore other studies have shown that the destination prefixes that carry lots of traffic usually have stable BGP routes.
Thu, 03/10/2011 - 22:10 by Olivier Bonaventure • Categories:
Introduced in RFC1323, the TCP timestamp option enables TCP hosts to better estimate the round-trip time by adding a timestamp to each transmitted TCP segment. These timestamps are also useful for high bandwidth transfer to protect against the reutilisation of the same TCP sequence number for different segments during the same MSL. These timestamps are supported by most TCP implementations today.
Thu, 03/10/2011 - 15:41 by Olivier Bonaventure • Categories:
In the early 1990s, the T/TCP extension to TCP was proposed to allow hosts to exchange data without being forced to wait until the end of the three way handshake. Specifications ( RFC1379 and RFC1644) and implementations were written, but this TCP extension has never been largely used.