{"id":178,"date":"2011-02-01T14:49:36","date_gmt":"2011-02-01T13:49:36","guid":{"rendered":"https:\/\/samovar2022.int-evry.fr\/index.php\/2011\/02\/01\/soutenance-these-de-bakr-sarakbi\/"},"modified":"2020-09-04T18:47:17","modified_gmt":"2020-09-04T16:47:17","slug":"soutenance-these-de-bakr-sarakbi","status":"publish","type":"post","link":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/2011\/02\/01\/soutenance-these-de-bakr-sarakbi\/","title":{"rendered":"SOUTENANCE : Th\u00e8se de Bakr Sarakbi"},"content":{"rendered":"

jeudi 10 f\u00e9vrier 2011
\nRoutage inter-domaine
\n<\/strong><\/p>\n

La soutenance aura lieu le Jeudi 10 F\u00e9vrier 2011 \u00e0 10H30 en salle A001-A003<\/p>\n

Composition du Jury:<\/strong><\/p>\n

– Timothy G. Griffin, Rapporteur, Universit\u00e9 de Cambridge
\n– Patrick S\u00e9nac, Rapporteur, ISAE, LAAS\/CNRS
\n– Khaldoun Al Agha, Examinateur, Universit\u00e9 Paris-Sud
\n– Marcelo dias de Amorim, Examinateur, UPMC
\n– Ana Cavalli, Directrice de these, Telecom SudParis
\n– St\u00e9phane Maag, Encadrant, Telecom SudParis<\/p>\n

Abstract<\/strong><\/p>\n

Internet is the hugest network the humanity has ever known. It provides a large number of various services to more than two billion users. This complex and growing topology lacks stability, which we can notice when a voice call is dropped, when a web page needs to be refreshed, etc. The initiator of this instability is the frequent events around the Internet. This motivates us to unleash a profound study to tackle Internet stability and suggest solutions to overcome this concern.<\/p>\n

Internet is divided into two obvious levels: AS (Autonomous System) level and router level. This distinction is reflected on the routing protocols that control the Internet traffic through two protocol
\ntypes: exterior (inter-AS) and interior (intra-AS). The unique used exterior routing protocol is the external mode of BGP (External Border Gateway Protocol), while there are several used internal routing protocols.<\/p>\n

Therefore, stabilizing the Internet is correlated to the routing protocol stability, which directs such efforts to the investigation of routing protocol (BGP) behavior. Studying BGP behaviors results in that its external mode (eBGP) suffers from long convergence time which is behind the slow response to topology events and, in turn, the traffic loss. Those studies state also that BGP internal mode (iBGP) suffers from several types of routing anomalies that causes its divergence.<\/p>\n

Therefore, we propose enhancements for both BGP modes: eBGP and iBGP and try to meet the following objectives: Scalability, safety, robustness, correctness, and backward compatibility with current version of BGP. Our eBGP proposal eliminates the transient disconnectivity caused by slow convergence by suggesting a backup strategy to be used upon the occurrence of a failure. IBGP proposal
\n(skeleton) gives an alternative to the existing internal configurations, that we prove its freeness of anomalies.<\/p>\n

Validation methods are essential to prove that the suggested enhancements satisfies the attended objectives. Since we are tackling an interdomain subject, then it is not possible to do validation in the real Internet. We suggested several validation methods to show that our enhancements meet the above objectives. We used simulation environment to implement eBGP backup solution and observe the convergence time and the continuous connectivity. We relied on two
\ntools: brite and rocketfuel to provide us with inter and intra AS topologies respectively. And to prove the safety of our approaches we employed an algebraic framework and made use of its results.<\/p>\n

R\u00e9sum\u00e9<\/strong><\/p>\n

Internet est le r\u00e9seau le plus gigantesque que l’humanit\u00e9 ne se soit pourvu. Il fournit un nombre important de services \u00e0 plus de deux milliards d’utilisateurs. Cette topologie grandissante et complexe p\u00eache en stabilit\u00e9, ce qui peut notamment \u00eatre constat\u00e9 quand un appel voix est interrompu, quand une page web \u00e0 besoin d?\u00eatre rafra\u00eechie, etc. L’initiateur de cette instabilit\u00e9 est l’ensemble des \u00e9v\u00e9nements constat\u00e9s dans l’Internet. Ceci nous motive \u00e0 une \u00c9tude profonde de la stabilit\u00e9 d’Internet afin de sugg\u00e8re des solutions \u00e0 cette probl\u00e9matique.<\/p>\n

Internet est divis\u00e9 en deux niveaux de base: le niveau AS (Autonomous
\nSystem) et le niveau de routage. Cette distinction se r\u00e9percute dans les protocoles de routage qui contr\u00f4lent le trafic Internet \u00e0 travers deux types de protocoles: ext\u00e9rieur (inter-AS) et int\u00e9rieur (intra-AS). L’unique protocole de routage ext\u00e9rieur utilit\u00e9 est le mode externe de BGP (External Border Gateway Protocol) tandis qu’il en existe plusieurs de type int\u00e9rieur.<\/p>\n

De fait, la stabilisation de l’Internet est corr\u00e9l\u00e9e \u00e0 la stabilit\u00e9 des protocoles de routage. Cela pousse les efforts de traitement de l?instabilit\u00e9 de l’Internet \u00e0 \u00c9tudier le comportement du protocole de routage (BGP). Analyser les r\u00e9sultats des comportements de BGP dans son mode externe (eBGP) souffre d’un temps de convergence important menant notamment \u00e0 des r\u00e9ponses lentes des \u00e9v\u00e8nements de topologie et, \u00e0 terme, \u00e0 la perte du trafic. Les \u00e9tudes \u00e9tablissent \u00e9galement que le mode interne de BGP (iBGP) souffre de plusieurs types d’anomalies de routage causant la divergence.<\/p>\n

Afin d’illustrer la stabilit\u00e9 de BGP, nous avons besoin d’un mod\u00e8le de routage qui formule la proc\u00e9dure de d\u00e9cision et le flot de signalisation. De plus, les am\u00e9liorations de BGP ne peuvent pas \u00eatre ais\u00e9ment valid\u00e9es dans l’Internet, rendant ainsi les mod\u00e8les de BGP indispensables \u00e0 une validation formelle. De fait, la premi\u00e8re \u00e9tape dans l?\u00e9tude du routage inter-domaine est de d\u00e9finir un mod\u00e8le appropri\u00e9 permettant la formulation de ses op\u00e9rations et de prouver sa correction.<\/p>\n

Nous avons propos\u00e9 deux mod\u00e8les compl\u00e9mentaires: topologique et fonctionnel, avec lesquels nous avons formul\u00e9 le processus de convergence du routage et d\u00e9montr\u00e9 la s\u00e9curit\u00e9 et la robustesse de nos solutions d’inter\/intra-AS. Notre proposition d’inter-AS \u00e9limine les d\u00e9connections transitoires caus\u00e9es par une faible convergence d’eBGP en sugg\u00e9rant une strat\u00e9gie de backup lors d’une panne. Notre proposition d’intra-AS (skeleton) donne une alternative aux configurations internes existantes, pour laquelle nous avons montr\u00e9 l’absence d’anomalies.<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

jeudi 10 f\u00e9vrier 2011 Routage inter-domaine La soutenance aura lieu le Jeudi 10 F\u00e9vrier 2011 \u00e0 10H30 en salle A001-A003 Composition du Jury: – Timothy G. Griffin, Rapporteur, Universit\u00e9 de Cambridge – Patrick S\u00e9nac, Rapporteur, ISAE, LAAS\/CNRS – Khaldoun Al Agha, Examinateur, Universit\u00e9 Paris-Sud – Marcelo dias de Amorim, Examinateur, UPMC – Ana Cavalli, Directrice […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"","ocean_second_sidebar":"","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"","ocean_custom_header_template":"","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"","ocean_menu_typo_font_family":"","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"on","ocean_gallery_id":[],"footnotes":""},"categories":[7],"tags":[],"class_list":["post-178","post","type-post","status-publish","format-standard","hentry","category-uncategorized-fr","entry"],"_links":{"self":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/178","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/comments?post=178"}],"version-history":[{"count":1,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":2040,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/178\/revisions\/2040"}],"wp:attachment":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/media?parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/categories?post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/tags?post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}