SRP Algorithm Simulation By:Andrey Klinger Michael Gustus Evgeny Muzikantov Supervisor: Itai Dabran

Introduction

The Spatial Reuse Protocol (SRP) was developed by Cisco for use with ring-based media. It derives its name from the spatial reuse properties of the packet handling procedure. SRP is the underlying technology used in the Cisco Dynamic Packet Transport (DPT) family of products.

Introduction SRP uses a bidirectional dual counter-rotating ring topology. The rings are referred to as "inner" and "outer". Both rings are concurrently utilized for transporting data and SRP control packets. SRP uses a bidirectional dual counter-rotating ring topology. The rings are referred to as "inner" and "outer". Both rings are concurrently utilized for transporting data and SRP control packets.

Introduction Protocol qualities Support of priority trafficSupport of priority traffic Fairness among nodes using the ring (not implemented in this project)Fairness among nodes using the ring (not implemented in this project) Support for ring based redundancy, like wrapSupport for ring based redundancy, like wrap Scalability across a large numberScalability across a large number of nodes attached to a ring

Goals

Our main goal was to learn the SRP protocol and implement it over UDP.Our main goal was to learn the SRP protocol and implement it over UDP.

Goals Protocol implementation tasks: 1.Basic node functionality that includes Layer2 accounting and SRP high/low priority queues. 2.Ring topology discovery. 3.Ring selection algorithm and wrap recovery.

Implementation

The project consists of 2 programs: Node programNode program Master programMaster program

Implementation The Node Sends and receives data packets over wrapped/unwrapped rings.Sends and receives data packets over wrapped/unwrapped rings. Sends and receives topology packets.Sends and receives topology packets. Unicast and Multicast sending.Unicast and Multicast sending. Gathering statistics of it’s behavior.Gathering statistics of it’s behavior.

Implementation The Node consists of 3 modules: 1.Hardware emulation module Layer-2 senders, receivers and buffers. 2.Software emulation module Layer-3 sender/receiver, topology discovery. 3.Testing module Generates traffic according to some schema. Log performance and draw graphs.

Implementation

User Interface

Implementation The Node provides different info about itself: Topology logTopology log Layer-2 Sender and Receiver logsLayer-2 Sender and Receiver logs Statistics logStatistics log Errors logErrors log

Implementation Connects between nodes.Connects between nodes. Changes the throughput of the ring.Changes the throughput of the ring. Changes the topology request timeout for the nodes.Changes the topology request timeout for the nodes. Master Provides simple, user-friendly, graphic interface to control the ring character-istics and its state. Used to set network parameters before and during simulation.

Implementation User Interface

The user guide

There are 2 work modes available: Master mode. Network with Master. All simulator options are available in this mode.Master mode. Network with Master. All simulator options are available in this mode. Node mode. Network without Master. Some options are not available.Node mode. Network without Master. Some options are not available.

The user guide 1.1 Adding nodes to network Run Node application on any computer you want to run it on. The following window appears:

The user guide 1.2 In Master mode After you added all the nodes you wanted to the network, the Master screen will show something like this: Connect

The user guide 2.0 Starting simulation In Master mode click Actions | Run, or if you didn't connect yet: Action | Connect & Run or just press the "GO" button

The user guide 3.0 Choosing testing scheme You can let the network run as it is, with just occasional topology packets being sent.You can let the network run as it is, with just occasional topology packets being sent. You can specify a sending scheme for each node.You can specify a sending scheme for each node. You can give all node same scheme file by opening it at Master (the file canYou can give all node same scheme file by opening it at Master (the file can still specify different schemas for each Node).

The user guide 3.1 Scheme file format

The user guide 4.0 Viewing graphs 4.0 Viewing graphs 6 graphs are shown on each Node: Left sender and right sender.Left sender and right sender. Transmit left low & Transmit right low buffers.Transmit left low & Transmit right low buffers. Transit 2left low buffer & Transit 2right low buffers.Transit 2left low buffer & Transit 2right low buffers.

Changing network options

Forcing wrap In Master mode, double click on a link. It will change link status from Connected (bold green) to Wrapped (dashed red). To remove wrap, double click on the link again.In Master mode, double click on a link. It will change link status from Connected (bold green) to Wrapped (dashed red). To remove wrap, double click on the link again.

Changing network options ThroughputThroughput Limit throughput of each link to given amount of bytes/second. Topology timeoutTopology timeout The time, Node will wait for any topology packet before generating its own, is a random number distributed uniformly between given timeout, and given timeout times 2. Master Options

And now… Lets see some SRP in action…