10/04/2001 Associate Professor CS Department University of Valenciennes France Dr. Dhavy Gantsou

10/04/2001 Targeting Ada95/DSA for Distributed Simulation of Multiprotocol Networks

10/04/2001 Networking backgroung

10/04/2001 Today ’s network technologies are designed for a specific purpose

10/04/2001 n Standard IP network (internet) operates on a ’’best-effort’’ basis - treats all traffic equally - may discard packets may delay traffic mostly used to enable access to a wide range of non-IP applications for low speed legacy applications (ftp, , http, etc)

10/04/2001 n Switch technology networks (ATM, SONET/SDH, MPLS) for high-speed applications garantees : - Quality of Service (QoS) * Traffic engineering * Differentiated service levels - Predictability (Real-time) - Security

10/04/2001 n Switch technology networks (ATM, SONET/SDH, MPLS) Is now using standard Internet to provide access to non-IP applications (Voice, B2B, real-time video, etc)

10/04/2001 Majority of traffic IP-based Need for multiservice (multiprotocol) network

10/04/2001 multiservice network ? = Network infrastructure, suitable for the full range of standard Internet, as well as switch technology services.

10/04/2001 At the heart of a multiprotocol architecture is the ability of routing protocols to: deliver differentiated services deliver differentiated services satisfy security concerns satisfy security concerns garantee predictability (Real-time) garantee predictability (Real-time) Manage an ever-growing network Manage an ever-growing network

10/04/2001 Need for distributed real-time routing protocols or distributed real-time extended versions of existing protocols Implementation + simulation of prototypes

10/04/2001 Simulation ? n Conventional (batch) sequential sequential parallel (on shared memory platforms) parallel (on shared memory platforms) n Interactive sequential sequential on cluster of workstations (Distributed interactive Simulation ’’DIS’’) on cluster of workstations (Distributed interactive Simulation ’’DIS’’)

10/04/2001 DIS widely available platforms widely available platforms computing performance computing performance naturally express the real word network architecture naturally express the real word network architecture protocol software same as simulation code protocol software same as simulation code

10/04/2001 DIS : which middleware ? Requirements Requirements n Real-time n Reliability n Scalability n Security n Performance Middleware n MPI n Sockets n OO Middleware Java RMI CORBA Ada95 DSA

10/04/2001 Point-to-point LSI exchange in OSPF Protocol Open Shortest Path First R1 R2 R5 R3 R4

10/04/2001 Shared memory based LSI exchange R1 DR (R2)BDR(R5) R3 R4

10/04/2001 Building prototypes of object-based real-time distributed routing protocols n Identifying protocol entities n Modeling and implementing entities using suitable Ada95 and/or DSA constructs

10/04/2001 Case study DIS of the BGP4 Decision algorithm Principle of the decision algorithm When a BGP4 (Border Gateway Protocol version4) router receives updates from multiple AS, it must run the decision algorithm to choose the single best path for reaching a destination. Once choosen, BGP propagates the path to its neighbors

10/04/2001 BGP_R3 AS 200 AS 300 AS 400 AS 500 BGP_R5BGP_R4 BGP_R2 BGP_R7 BGP_R1 BGP_R6 AS 700 AS 100 AS 600 BGP Path selection

10/04/2001 Modeling & implementation

10/04/2001 Two kinds of distributed objects n Objects supporting general purpose of distributed object computing Remote_Call_Interface Partition Remote_Call_Interface Partition include a declaration of a RACW include a declaration of a RACW

10/04/2001 with Common, Interface; package Object_Adapter is pragma Remote_Call_Interface; Max_Devices : constant Positive := 15; --End Routers and Intermediary Routers Max_neighbors : constant Positive := Max_Devices; type Router_Class_Ref is access all Interface.Router_Class'Class; type Router_References is record Router_Ref : Router_Class_Ref ; hostname : Common.String_Host; end record; type References_List is array(Positive range <>) of Router_References; type Neighbor_Type is record Count : Natural := 0; List : References_List(1..max_neighbors) := (others => (null, (others => ' '))); end record; procedure Router_Registry(Data : in Router_Class_Ref; Is_router : in Boolean; Hostname : in Common.String_Host); function get_neighbor_list(hostname : in Common.String_Host) return Neighbor_Type; function get_link_array return Router_Link_List; end Object_Adapter; Object associating logical references to actual object implementation

10/04/2001 Two kinds of distributed objects n Objects dealing with the implementation of the protocol entities the protocol entities normal package normal package Pure, Pure, including the declaration of one class Remote_Types, or Remote_Types, or Shared_Passive categorized Partition Shared_Passive categorized Partition

10/04/2001 package Interface is pragma Pure; type Router_Class is abstract tagged limited private; type Community_Type is (no_export,no_advertise, internet); type Exchanged_Attributes is record As_Path : Positive; Origin : Common.String_Host; Next_Hop : Common.String_Host; Local_Preference : Natural; community : Community_Type; end record; procedure send (Data : access Router_Class; Update : in Exchanged_Attributes; Src_Hostname : in Common.String_Host) is abstract; procedure receive (Data : access Router_Class; Update : in Exchanged_Attributes) is abstract; Private type Router_Class is abstract tagged limited null record; end Interface ; Root class for all Router implementation

10/04/2001 with Common, Interface, Object_Adapter ; package Bgp_Isp_Router is type Bgp_Isp_Router_Class is new Interface.Router_Class with record hostname : Common.String_Host; neighbors : Object_Adapter.Neighbor_Type; end record; procedure send(Data : access Bgp_Isp_Router_Class; Update : in Interface.Exchanged_Attributes; Src_Hostname : in Common.String_Host); procedure receive(Data : access Bgp_Isp_Router_Class; Update : in Interface.Exchanged_Attributes); end Bgp_Isp_Router; Derived class BGP_ISP_Router

10/04/2001 Simulation :Working environment n Gnat-3.13p, ACT Ada95 compiler (free) n Glade-3.13p, ACT implementation of DSA (free) n A 100MB ethernet connecting: n 15 Sun UltraSPARCs running Solaris 2.6, n 1 Sun Enterprise running Solaris 2.7

10/04/2001 Simulation : Empirical test

10/04/2001 A usual running 1) From : ultraistv6 To : ultraistv9 Message : good Router [ultraistv6] -> Running decision algorithm... Router [ultraistv6] -> Send message through ultraistv4... BGP_Router [ultraistv9] -> Received message'good -> BGP_Router[ultraistv6] -> ISP[ultraistv4] ’ 2) >From : ultraistv6 To : ultraistv9 Message : HS Router [ultraistv6] -> Running decision algorithm... Router [ultraistv6] -> Send message through ultraistv4... BGP_Router [ultraistv9] -> Received message'HS -> BGP_Router[ultraistv6] -> ISP[ultraistv4]'

10/04/2001 B unusual running : psd |grep ‘gantsou' 8 R gantsou a1e :21:14 pts/1 0:00 -csh 8 S gantsou a381f0 375 ddd54 19:12:39 ? 0:00 /prof/gantsou/V4/bin/proxy1 --boot_ : kill ) >From : ultraistv6 To : ultraistv9 Message : Down Router [ultraistv6] -> Running decision algorithm... Router [ultraistv6] -> Send message through ultraistv4... Router failed ! (catch SYSTEM.RPC.COMMUNICATION_ERROR)

10/04/2001 4) >From : ultraistv6 To : ultraistv9 Message : restart Router [ultraistv6] -> Running decision algorithm... Router [ultraistv6] -> Send message through ultraistv4... Router failed ! (catch SYSTEM.RPC.COMMUNICATION_ERROR)

10/04/2001 >From : ultraistv6 To : ultraistv9 Message : Any change ? Router [ultraistv6] -> Running decision algorithm... Router [ultraistv6] -> Send message through ultraistv4... Router failed ! (catch SYSTEM.RPC.COMMUNICATION_ERROR) >From : ultraistv9 To : ultraistv6 Message : ISP2 down Router [ultraistv9] -> Running decision algorithm... Router [ultraistv9] -> Send message through ultraistv1... Router failed ! (catch SYSTEM.RPC.COMMUNICATION_ERROR)