XMSF Overlay Multicast Status Report

Transcription

1 XMSF Overlay Multicast Status Report Mark Pullen and ennis Moen George Mason University 2004 J. Mark Pullen 1 Network Service Requirements for Real Time istributed Virtual Simulation -XMSF Report, 2002 Network Quality of Service (QoS) end-to-end capacity, latency, jitter, and packet loss in a statistical sense Multicast many-to-many group communication Reliable Multicast Transport high confidence of delivery End- to- end network status and performance monitoring need to know what the network is doing for you Multi- sensor systems must manage streaming data with low latency 2004 J. Mark Pullen 2

2 What is multicasting? Multicasting: sending a packet to a group of addresses in a network broadcast: sending to all addresses - impractical in WN IPmc allows packets to be sent to group addresses delivered in parallel class address and greater LNs have inherent broadcast/multicast capability In WN, set of all nodes in a multicast group forms a tree grows from the node that starts the group Routers at forks in tree must replicate packets commercial routers available that perform this function Multicast requires a different routing protocol from unicast routing creates the multicast tree 2004 J. Mark Pullen 3 Network with Multicast Tree the network duplicates the packets E F G H J 2004 J. Mark Pullen 4

3 IP Multicast irectionality IPmc uses a many- to- many model of packet delivery equivalent to full duplex for multicast any participating host can send to the group useful for collaborative- style applications a very appealing model but increases complexity of the network layer considerably IETF recently developed an approach called Source Specific Multicast (SSM) that uses a one- to- many model equivalent to half duplex for multicast only one host can send to the group useful for presentation- style applications 2004 J. Mark Pullen 5 One-to-Many Multicast J. Mark Pullen 6

4 Internet Multicast Services Today IP multicast over the Internet not widely deployed IETF focus is on one-to-many multicast ommercial viability lacking for IP multicast across the Internet Result: interest in multicast based in end systems not network End- to- end argument: push complexity up the stack Example: TP is complex, IP is simple 2004 J. Mark Pullen 7 pplication Layer Multicasting Network EducationWare System PP1 LIENT INTERFE PP2 PP2 PP1 PP3 LIENT INTERFE TRNSPORT LYER MULTIST PP3 LIENT INTERFE PP1 PP2 PP3 local UP WN TP LIENT INTERFE PP3 PP1 PP J. Mark Pullen 8

5 Overlay Multicast provided by a host-based middle layer E INTERNET F G IP Multicast tree: G E F H J 2004 J. Mark Pullen 9 XOM Overlay XOM 1 XOM 2 Router Router XOM 4 XOM 3 XOM 5 Router Router XOM 6 XOM J. Mark Pullen 10

6 XOM rchitectural Layers Generic lass efinition Interface (SRMP Example) Registry Routing Group Management Path Management Join/leave Security ddress apacity/latency Node emand Routing Table Path Optimization Packet Send/Receive istribute Messages UP IP Listen to Ports lass QoS/ Queueing 2004 J. Mark Pullen 11 XOM Group Membership G 2 = {,, } XOM 3 Internet XOM 1 G 1 = {, } G 2 = {,, } XOM 2 G 1 = {, } pplication sending implies routing to group G 3 = {G 1 υ G 2 } 2004 J. Mark Pullen 12

7 Group ggregation Overlay (Optimum Path Overlay) XOM 1 (g 0, g 1, g 2, g 3 ) XOM 2 Multicast Groups Group Members g 0 XOM 1,2,3,4 g 1 XOM 1,2,3,4 g 2 XOM 1,2,3 g 3 XOM 1,2 T 0 Internet XOM 4 (g 0, g 1 ) ggregate Trees Tree Tree Links (arcs) T 0 1-4, 4-2, 4-3 Groups g 0, g 1, g 2, g 3 share one aggregate tree T 0. T 0 is a perfect match for g 0 and g 1, but is a leaky match for g 2 and g 3. Trades off path utilization inefficiency for lower path Management overhead. (g 0, g 1, g 2, g 3 ) (g 0, g 1, g 2 ) XOM J. Mark Pullen 13 XOM Functional Model Prototype Test Scenario Traffic Generator SRMP Packet Sender Host hannel bstraction for Multicast hannel (S,G) Routing Table for hannel (S,G) Packet Receiver UP IP 2004 J. Mark Pullen 14

8 XOM Prototype Registries Other XOM Sites Statistics WN stats LN stats incoming Internet MulticastRouter* (Java or ++) outgoing routing info Routing data routing table IPmc Host multicast to/from WN *ll modules except IPmc Host 2004 J. Mark Pullen Router are Java 15 Prototype Lab Test Scenarios With IS-like traffic: Java version 3000 messages per second ++ version 8000 messages per second XOM 1 XOM 1 XOM4 XOM 4 XOM 2 XOM 3 XOM 2 XOM 3 Test 1. XOM n-degree of 3 Test 2. XOM n-degree of J. Mark Pullen 16

9 XOM Prototype Message elay degree 3-degree E L Y M S E Objects 2004 J. Mark Pullen 17 XOM Prototype Message Loss Ratio 30.00% 25.00% L O S S 20.00% 15.00% 10.00% 2 subnets 3 subnets 5.00% 0.00% Objects 2004 J. Mark Pullen 18

10 Setting Up the XOM Prototype One host per subnet runs XOM lso can run applications ut for highest performance a separate host is best urrent prototype does not support a registry Each XOM must know the IP address of all others The XOMs exchange routing data and create a separate tree per source XOM Two configurations available 1. Pure Java 2. Router module assisted by ++ (better performance) Multicast applications on LN hosts run without modification XOM is transparent except in received packet from address 2004 J. Mark Pullen 19 XOM Prototype ommand Line Parameters registryddress numberofmulticastgroups lowestmddress lowest port routingupdateinterval usetp partnerhostddresses 0 for now count of groups/ports we will support first group address to multicast from the subnet, dotted decimal notation (other addresses follow in sequence) first UP port to multicast (each address will get one port, in sequence) time in ms between routing updates 0 for now up to 20 XOM host IP addresses in dotted decimal notation; these partners will be used without checking registry 2004 J. Mark Pullen 20

11 onclusions and Future Work Initial results indicate overlay networking is a promising strategy for providing many-to-many multicast in the open internetwork environment of XMSF. We are working on an architecture specification based on the properties of distributed simulation traffic plus recent networking research. working experimental prototype is available on our website. We plan to enhance this with better performance display. NPS is working on a Web-service-based registry and routing information system. Our system will be demonstrated at I/ITSE, supporting a multicast HL federation and Web Service-based Interest Management (WSIM) J. Mark Pullen 21 Publications vailable on Pullen, J., "Reliable Multicast Network Transport for istributed Virtual Simulation," Proceedings of the 3rf IEEE Workshop on istributed Simulation and Real-Time pplications, 1999 Moen,. and J. Pullen, " Performance Measurement pproach for the Selectively Reliable Multicast Protocol for istributed Simulation," Proceedings of the 5h IEEE Workshop on istributed Simulation and Real-Time pplications, 2001 Moen,. and J. Pullen, Enabling Real-Time istributed Virtual Simulation over the Internet Using Host-based Overlay Multicast Proceedings of the 7th IEEE Workshop on istributed Simulation and Real-Time pplications, 2003 Moen,. and J. Pullen, "Implementation of Host-based Overlay Multicast to Support Web ased Services for RT-VS," Proceedings of the 8th IEEE Workshop on istributed Simulation and Real-Time pplications, J. Mark Pullen 22