代写CSCI-GA、代做Java编程语言

日期：2024-05-14 09:49

New York University

Computer Science Department

Courant Institute of Mathematical Sciences

Course Title: Data Communications & Networks Course Number: CSCI-GA.2662-001

Assignment 8: Final Project

I. Due

Friday May 14, 2024 by 11:59 pm ET.

II. Objectives

Software-defined networking (SDN) is a recent paradigm for running networks. As

per the networking layer topics covered in the course, the network is divided into

the control and data planes. The control plane provides a set of protocols and

configurations that set up the forwarding elements (hosts, switches, and routers) so

that they can forward packets. This includes, for example, ARP resolution, DNS,

DHCP, the Spanning Tree Protocol, MAC learning, NAT and access control

configuration, as well as all of the routing protocols. Usually, switches and routers

have to run all of these protocols, detect topology changes, issue heartbeats, manage

caches, timeouts, etc. Meanwhile, in many cases network administrators achieve

desired goals with the network indirectly, by tweaking parameters in the routing

protocols like link weights and local BGP preference. While the data plane is nicely

organized in the familiar layered scheme, the aggregate structure of the control

plane is a lot less clean.

SDN is a radical departure from this organization. The main idea is a separation of

the control plane from the forwarding elements. SDN switches and routers do not

run control plane protocols and mostly only forward packets based on matching of

packet predicates to a set of forwarding rules. They export a simple API to

configure these rules, as well as some feedback about current and past packets. An

accepted standard for this API is the OpenFlow protocol, which has been

implemented by dozens of switch vendors and has fostered a rich software

ecosystem. The intelligence of the control plane is (logically) centralized in a

network controller. The controller decides which rules to install based on its

configuration, and on a global view of the network topology and flows.

In this project, you will implement the logic in such a controller to manage the

following:

1. A layer-3 routing application that installs rules in SDN switches to forward

traffic to hosts using the shortest, valid path through the network. Your

application logic will manage the efficient switching of packets among hosts in

a large LAN with multiple switches and potential loops. You will write the code

for a SDN controller application that will compute and install shortest path

routes among all the hosts in your network. SDN as described is suitable for

networks under a single administrative domain (e.g., the network in a single

AS), but there are ongoing research projects to use its flexibility across

domains, integrating with and perhaps even replacing BGP.

2. A distributed load balancer application that redirect new TCP connections to

hosts in a round-robin order.

As always, the NYU and class policy about plagiarism must be followed in this

project. If you use ANY code in your project that is not of your own creation,

then you MUST attribute that code to the author, even if you modify it (ANY

modification).

III. References

1. Slides and handouts posted on the course Web site

2. Textbook chapters as applicable

3. Mininet network emulator documentation (http://mininet.org/)

4. Openflow documentation (https://www.opennetworking.org/sdn-resources/onfspecifications/openflow)

5. Open vSwitch switch software documentation (http://openvswitch.org)

6. Floodlight Java-based SDN controller documentation

(https://floodlight.atlassian.net/wiki/spaces/floodlightcontroller/overview)

7. If you have additional questions about SDN, OpenFlow, or Floodlight you may

want to consult: openflow-switch-v1.5.1.pdf (opennetworking.org) (sections 2, 3,

and 5.1 - 5.4 are likely to be the most useful), and Floodlight-plus Javadoc

8. Additional readings:

? Software Defined Networking Concepts

? The Road to SDN: An Intellectual History of Programmable Networks

? SDN Reading List

IV. Software Required

1. Microsoft Word

2. Win Zip as necessary

3. Oracle VirtualBox

4. Virtual Box Image with all necessary software provided

5. Java Programming language, Eclipse, and other development tools installed in

Virtual Box Image provided

6. Additional code for Part 4

V. Assignment

This is a final take-home project that can be completed individually or as a team

(only two students per team).

1. Background:

You will run the code for this project in an emulated network inside of a single

Linux VM. You will use the Mininet network emulator, which is designed to

emulate arbitrary topologies of emulated OpenFlow switches and Linux hosts.

It uses container-based virtualization for very light-weight emulated nodes. The

switches in your network run the open source Open vSwitch switch software,

which implements the Openflow protocol. The switches connect to an

Openflow network controller, and you will use Floodlight, a relatively mature

Java-based controller. We will use OpenFlow version 1.0 for this project. Your

SDN applications will be written in Java and run atop the Floodlight OpenFlow

controller. You will use Mininet to emulate a variety of network topologies

consisting of OpenFlow switches and hosts.

Code you run on Mininet is ready to run with no changes in real networks.

2. Environment Setup:

a. Install Oracle VirtualBox as necessary.

b. Download the Virtual Box Image with all necessary software provided. It is

a .ova image that will enable you to run the necessary software on your

computer using the latest version of Oracle VirtualBox. To install the .ova

file go to File and Import Appliance on VirtualBox. This VM uses “mininet”

as username and password.

c. To ssh into the VM from your host computer, log in first using the GUI,

open a terminal, and type ifconfig. This will show you the IP addresses of

the VM. You will be able to connect to one of them from your host computer

via ssh. The VM also has Eclipse installed, which you can use inside the

VirtualBox graphical console or remotely via X. Once you have ssh’d into

the VM, you can go through the following steps to run your control

applications.

d. Optional (see acknowledgement in item 8 below):

Refactor edu.brown.cs.sdn.apps.sps to edu.nyu.cs.sdn.apps.sps

e. Compile Floodlight and your applications:

$ cd ~/project3/

$ ant

This will produce a jar file FloodlightWithApps.jar that includes the

compiled code for Floodlight and your SDN applications.

f. Start Floodlight and your SDN applications:

$ java -jar FloodlightWithApps.jar -cf l3routing.prop

The above command will start Floodlight and only your layer-3 routing

application. The .prop file configures your application.

Note: For future reference when working on part 4, you can start both your

layer-3 routing and load balancer applications by using

loadbalancer.prop for the -cf (configuration file) argument. The

loadbalancer application code is provided separately.

You should always start Floodlight and your SDN applications

before starting Mininet. Also, we recommend that you restart Floodlight

and your SDN applications whenever you restart Mininet.

Note: In the VirtualBox image, it is possible that the system will start an

openvswitch-controller process by default, which means your

Floodlight controller will not be able to bind to port 6633. To prevent it

from starting the next time you boot up, do:

$ sudo update-rc.d -f openvswitch-controller remove

When Floodlight starts, you should see output like the following:

23:18:45.874 INFO [n.f.c.m.FloodlightModuleLoader:main] Loading modules from file shortestPathSwitching.prop

23:18:46.277 INFO [n.f.c.i.Controller:main] Controller role set to MASTER

23:18:46.285 INFO [n.f.c.i.Controller:main] Flush switches on reconnect -- Disabled

23:18:46.302 INFO [ArpServer:main] Initializing ArpServer...

23:18:46.302 INFO [ShortestPathSwitching:main] Initializing ShortestPathSwitching...

23:18:48.533 INFO [n.f.l.i.LinkDiscoveryManager:main] Setting autoportfast feature to OFF

23:18:48.579 INFO [ArpServer:main] Starting ArpServer...

23:18:48.580 INFO [ShortestPathSwitching:main] Starting ShortestPathSwitching...

23:18:48.700 INFO [o.s.s.i.c.FallbackCCProvider:main] Cluster not yet configured; using fallback local configuration

23:18:48.701 INFO [o.s.s.i.SyncManager:main] [32767] Updating sync configuration ClusterConfig

[allNodes={32767=Node [hostname=localhost, port=6642, nodeId=32767, domainId=32767]},

authScheme=NO_AUTH, keyStorePath=null, keyStorePassword is unset]

23:18:48.790 INFO [o.s.s.i.r.RPCService:main] Listening for internal floodlight RPC on localhost/127.0.0.1:6642

23:18:48.978 INFO [n.f.c.i.Controller:main] Listening for switch connections on 0.0.0.0/0.0.0.0:6633

Keep the terminal with Floodlight open, as you will need to see the output

for debugging. Use another terminal for the next step.

g. Start Mininet:

$ sudo ./run_mininet.py single,3

The above command will create a topology with a single SDN switch (s1)

and three hosts (h1 - h3) directly connected to the switch:

You can change the number of hosts by changing the numeric value

included in the arguments to the run_mininet.sh script. You can also start

Mininet with four other topologies:

? linear,n: a chain of n switches with one host connected to each

switch; for example, linear,3 produces the following topology:

? tree,n: a tree of depth n with a single root switch (s1) and two hosts

connected to each leaf switch; for example tree,2 produces the

following topology:

? assign1: creates the following topology (the name is this way for

historical reasons):

? triangle: creates the following topology:

? mesh,n: a complete graph with n switches and one host attached to

each switch; for example, mesh,5 produces the following topology:

? someloops: creates the following topology:

Once mininet has started, you should see Floodlight produce output like the

following:

23:24:10.304 INFO [n.f.c.i.OFChannelHandler:New I/O server worker #2-1] New switch connection from /127.0.0.1:58911

23:24:10.329 INFO [n.f.c.i.OFChannelHandler:New I/O server worker #2-1] Disconnected switch [/127.0.0.1:58911 DPID[?]]

23:24:11.016 INFO [n.f.c.i.OFChannelHandler:New I/O server worker #2-2] New switch connection from /127.0.0.1:58912

23:24:11.101 INFO [n.f.c.i.OFChannelHandler:New I/O server worker #2-2] Switch OFSwitchBase

[/127.0.0.1:58912 DPID[00:00:00:00:00:00:00:01]] bound to class class

net.floodlightcontroller.core.internal.OFSwitchImpl, writeThrottle=false,

description OFDescriptionStatistics [Vendor: Nicira, Inc., Model: Open vSwitch,

Make: None, Version: 2.0.2, S/N: None]

23:24:11.104 INFO [n.f.c.OFSwitchBase:New I/O server worker #2-2] Clearing all flows on switch

OFSwitchBase [/127.0.0.1:58912 DPID[00:00:00:00:00:00:00:01]]

23:24:11.107 WARN [n.f.c.i.C.s.notification:main] Switch 00:00:00:00:00:00:00:01 connected.

23:24:11.108 INFO [ShortestPathSwitching:main] Switch s1 added

23:24:11.138 INFO [ShortestPathSwitching:Topology Updates] Link s1:0 -> host updated

23:24:11.211 INFO [ShortestPathSwitching:Topology Updates] Link s1:1 -> host updated

23:24:11.212 INFO [ShortestPathSwitching:Topology Updates] Link s1:3 -> host updated

for debugging. Use another terminal for the next step.

h. You can now run commands (e.g., ping) and the like in Mininet. Note that

initially ping will not work, as your switches do not know how to do

anything. After your controller installs the correct rules, things should work.

3. Layer-3 “Shortest-Path Switching” Routing Application Implementation:

Your first SDN controller application consists of code that will run in an SDN

controller to compute, install, and maintain shortest paths on a large local area

subnet. Given a packet destined to an MAC address, your network will use a

shortest path among the switches to deliver it to the host. The hosts in the project

will not be changed in any way, it is only the switches in the network that will

behave differently. While all the hosts in this project will be in the same subnet,

we will not use any broadcasts, including for ARP. When a host wants to send

a packet to the IP address of another host in the network, it will first, as it usually

does, issue an ARP request. When this reaches the first switch, though, the

switch will send the ARP request to the controller instead of flooding the

request. The controller, who knows the topology, will respond to the ARP

request, through the same switch, to the original sender, with the MAC address

of the destination. The controller will also have installed rules on the switches

for forwarding to each destination MAC.

Your task is therefore to build a global shortest-path switching table and install

forwarding rules on the switches to implement these paths. You will build this

table on the controller based on global topology information the controller

gathers. Your application will construct route tables based on a global view of

the network topology. The appropriate route table will then be installed in each

SDN switch, and each SDN switch will forward packets according to the route

table installed by your application.

Differently from regular L2 switches or L3 routers, SDN switches do not hold

MAC learning tables or routing tables (used in traditional layer-3 routers).

Rather, they use a more general flow table structure, which can replace these,

as well as MAC learning tables (used in traditional layer-2 switches), and many

other constructs. Each entry, or rule, in a flow table has match criteria that

defines (on the basis of fields in Ethernet, IP, TCP, UDP, and other headers)

which packets the rule applies to. Each entry also has one or more

instructions/actions which should be taken for each packet that matches the

rule. There is no concept of a “gateway” in SDN flow tables, but that is okay—

your router only uses the gateway to determine how to rewrite a packet’s

destination MAC address to ensure correct layer-2 forwarding, and we are not

using traditional layer-2 forwarding in SDN.

Your layer-3 “Shortest-Path Switching” routing application will install entries

that match packets based on their destination IP address (and Ethernet type),

and execute an output action to send the packet out a specific port on the SDN

switch. (You will use other match criteria and additional instructions/actions

for the other SDN application you will write, which is described in Part 4 of

this project.) The match criteria serve the same purpose as the destination and

mask fields in a traditional route table, and the output action servers the same

purpose as the interface field in a traditional route table. In the aggregate, your

network will resemble a network in which all switches have converged with the

spanning tree protocol and MAC learning, with one important difference: your

topology is not constrained to a tree, as you are installing paths individually and

loops should not be a problem. In fact, you must test that your solution works

on topologies with loops.

After the rules are all installed, the process a host will go through to send an

IP packet to a destination IP address is as follows:

a. Host OS determines that the node is in the same subnet (will always

be true in this assignment). This means the node will send the packet

to the IP destination as an Ethernet frame destined to the MAC

address of the destination (as opposed to the MAC address of a

gateway or router).

b. Host OS issues an ARP request to determine the destination MAC

address (if not already cached at the OS).

c. The first switch to see the ARP request, rather than broadcasting it,

sends it to the controller as a PacketIn message.

d. The Floodlight module ArpServer (which we provide, see the util

package) will respond with the if this host has sent any Ethernet

frames before.

e. The host OS will send the IP packet to the destination’s MAC

address.

f. At each switch along the path to the destination (as determined

previously by your code), the packet will match on the destination

MAC address and be forwarded on the correct port.

3.1 Code Overview

You will complete the implementation of a Floodlight module in the file

ShortestPathSwitching.java in edu.brown.cs.sdn.apps.sps (or

edu.nyu.cs.sdn.apps.sps if you refactored that package earlier).

The file we provided already contains code to:

? Access host and topology information from other modules (or

applications) included with Floodlight – see the getHosts(),

getSwitches(), and getLinks()methods.

? Receive notifications about changes in the network: see the

deviceAdded(), deviceRemoved(), deviceMoved(),

switchAdded(), switchRemoved(), and

linkDiscoveryUpdate() methods

We have also provided code in the edu.brown.cs.sdn.apps.util

package (or edu.nyu.cs.sdn.apps.util) if you refactored that package

earlier) for:

? A Floodlight module that responds to ARP requests from hosts – see

ArpServer.java

? Telling a switch to install a rule in the flow table, remove rules from

the flow table, and send a packet – see SwitchCommands.java.

In this project we will install rules to reach all hosts we know about. In the

launch script for Mininet we have added instructions for all hosts to issue

an arping, which allows the controller to learn about the hosts’ presence

and populate its ARP cache.

3.2 To-Do’s

You need to complete the To-Do’s in ShortestPathSwitching.java to

install and remove flow table entries from SDN switches such that traffic is

forwarded to a host using the shortest path.

You should use either the Bellman-Ford or Djikstra algorithms to compute

the shortest paths to reach a host h from every other host h’ ∈ H, h ≠

h’ (H is the set of all hosts). You can use the getHosts(), getSwitches(),

and getLinks() methods to get the topology information that you need to

provide as input to the Bellman-Ford algorithm.

Once you have determined the shortest path to reach host h from h’, you

must install a rule in the flow table in every switch in the path. The rule

should match IP packets (i.e., Ethernet type is IPv4) whose destination

MAC is the MAC address assigned to host h. You can specify this in

Floodlight by creating a new OFMatch object and calling the set methods for

the appropriate fields. The rule’s action should be to output packets on the

appropriate port in order to reach the next switch in the path. You can

specify this in Floodlight by creating an

OFInstructionApplyActions object whose set of actions consists of a

single OFActionOutput object with the appropriate port number.

SDN switches have multiple flow tables (we discuss this more in Part 4

below). For now, you should install rules in the table specified in the

table class variable in the ShortestPathSwitching class. Also, your

rules should never timeout and have a default priority (both defined as

constants in the SwitchCommands class). When the topology changes you

will have to recompute a subset of the paths. For this assignment you may

choose to recompute all of the topology or be more efficient and only

remove and install the rules that need to change.

Part 3 Extra Credit:

? Implement flooding without loops (essentially calculate and install

a spanning tree for broadcasts).

? Implement ECMP on networks with multiple paths (determine the

number of paths between two nodes) and install rules that match on,

say, even and odd TCP ports!

3.3 Testing and Debugging

You should test your code by sending traffic between various hosts in the

network topology—Mininet’s built-in pingall command is very useful for

this. While you MUST handle loops in the topology correctly, you can

assume that the topology is connected (i.e., we will not test your code with

topologies where a host is unreachable from other hosts.)

To help you debug, you can view the contents of an SDN switchs flow tables

by running the following command in your mininet VM (not in Mininet

itself):

$ sudo ovs-ofctl -O OpenFlow13 dump-flows s1

This will output the contents of s1’s flow tables. Change the last argument

to output the flow tables from a different switch.

Triggering Event Handlers:

? You can trigger the linkDiscoveryUpdate(...) event handler by

running any of the following commands in Mininet (substituting switch

and host names as desired):

o link s1 s2 down — takes down the link between s1 and s2;

you can assume the network is a connected graph, so you should

never take down a link that would result in a disconnected graph

o link s1 s2 up — brings up the link between s1 and s2

o link s1 h1 down — takes down the link between s1 and h1;

this will also result in a deviceRemoved(...) event and the

isAttachedToSwitch() method for the Host object for h1 will

now return false

o link s1 h1 up — brings up the link between s1 and h1; this

will also result in a deviceMoved(...) event and the

isAttachedToSwitch() method for the Host object for h1 will

now return true

? You can trigger the deviceRemoved(...) event handler by taking down a

link between a switch and a host, as described above

? You can trigger the deviceMoved(...) event handler by bringing up a

link between a switch and a host, as described above

? You can trigger the switchRemoved(...) event handler by running the

following command in a regular terminal window (not in mininet):

$ sudo ovs-vsctl del-br s1

Note that once a switch is removed, you cannot easily add it back without

restarting mininet. You can assume the network is a connected graph, so

you should never remove a switch that would result in a disconnected graph.

Known Issue: when you issue a link ... down command, sometimes we

have seen mininet ressurect the link. This seems to be a problem with

Mininet. In case this happens, bringing the link down a second time seems

to kill it for good.

4. Distributed Load Balance Routing Application Implementation:

Networks employ load balancing to distribute client requests among a

collection of hosts running a specific service (e.g., a web server). In class, we

briefly discussed how DNS could be used to implement load balancing. Load

balancing is also commonly implemented using a special piece of hardware.

A hardware load balancer is placed in the network and configured with an IP

address (e.g., 10.0.100.1) and a set of hosts among which it should distribute

requests (e.g., 10.0.0.2 and 10.0.0.3). Clients wanting to communicate with

a service (e.g., a web server) running on those hosts are provided with the IP

address of the load balancer, not the IP address of a specific host. Clients initiate

a TCP connection to the IP address of the load balancer (10.0.100.1) and the

TCP port associated with the service (e.g., port 80).

For each new TCP connection, the load balancer selects one of the specified

hosts (usually in round robin order). The load balancer maintains a mapping of

active connections—identified by the client’s IP and TCP port—to the assigned

hosts.

For all packets sent from clients to the load balancer, the load balancer rewrites

the destination IP and MAC addresses to the IP and MAC addresses of the

selected host. The mapping information stored by the load balancer is used to

determine the appropriate host IP and MAC addresses that should be written

into a packet arriving from a client. For all packets sent from servers to clients,

the load balancer rewrites the source IP and MAC addresses to the IP and MAC

addresses of the load balancer.

Your second SDN application will implement the same functionality as a set of

hardware load balancers. Your application will be provided with a list of

virtual IPs and a set of hosts among which connections to the virtual IPs

should be load balanced. (We use the term virtual IP because the IP address

is not actually assigned to any node in the network.) When clients initiate TCP

connections with a specific virtual IP, SDN switches will send the TCP SYN

packet to the SDN controller. Your SDN application will select a host from a

pre-defined set, and install rules in an SDN switch to rewrite the IP and MAC

addresses of packets associated with the connection. You will also instruct the

SDN switch to match the modified packets against the flow rules installed by

your layer-3 routing application and apply the appropriate actions (i.e., send the

packets out the appropriate ports).

4.1 Code Overview

The code for your load balancer application will reside in the

LoadBalancer.java source file provided in finalproject-part4-

code.zip (see edu.wisc.cs.sdn.apps.loadbalancer package). The file

provided already contains code to:

? Receive a notification when a switch joins the network— switchAdded(...)

? Receive a packet from a switch when the packet did not match any

entries in the switch’s flow table—receive(...)

The LoadBalancerInstance class represents a single distributed load

balancer. (We use the term distributed because the load balancing is

performed at many switches, rather than at a single hardware load balancer.)

Each load balancer instance has a virtual IP address, virtual MAC address,

and set of hosts among which TCP connections should be distributed. The

instances class variable in the LoadBalancer class maps a virtual IP address

to a specific load balancer instance.

4.2 To-Do’s

It is recommended to refactor the package provided in finalproject-part4-

code.zip to edu.nyu.cs.sdn.apps.loadbalancer (see acknowledgment

in item 8). Also note that edu.wisc.cs.sdn.apps.l3routing is not used

in this project.

You need to complete the To-Do’s in LoadBalancer.java to:

? Install rules in every switch to:

o Notify the controller when a client initiates a TCP

connection with a virtual IP—we cannot specify TCP

flags in match criteria, so the SDN switch will notify the

controller of each TCP packet sent to a virtual IP which

did not match a connection-specific rule (described

below)

o Notify the controller when a client issues an ARP request

for the MAC address associated with a virtual IP

o Match all other packets against the rules in the next table

in the switch (described below)

These rules should be installed when a switch joins the network.

? Install connection-specific rules for each new connection to a

virtual IP to:

o Rewrite the destination IP and MAC address of TCP

packets sent from a client to the virtual IP

o Rewrite the source IP and MAC address of TCP packets

sent from server to client

Connection-specific rules should match packets on the basis of

Ethernet type, source IP address, destination IP address, protocol,

TCP source port, and TCP destination port. Connection-specific

rules should take precedence over the rules that send TCP packets

to the controller, otherwise every TCP packet would be sent to the

controller. Therefore, these rules should have a higher priority than

the rules installed when a switch joins the network. Also, we want

connection-specific rules to be removed when a TCP connection

ends, so connection-specific rules should have an idle timeout of 20

seconds.

? Construct and send an ARP reply packet when a client requests

the MAC address associated with a virtual IP

? Construct and send a TCP reset packet if the controller receives

a TCP packet that is not a TCP SYN

Multiple Tables

Your load balancer application should work in tandem with your layer-3

“Shortest-Path Switching” routing application. To achieve this, you will

need to leverage the multiple tables feature of OpenFlow switches. When

packets first arrive at an OpenFlow switch, they are matched against the

rules in table 0. The actions for these rules can specify that the packets be

modified, output, sent to the controller, and/or matched against the rules in

a different table.

Your load balancer application should install rules in the table specified in

the table class variable in the LoadBalancer class—set to table 0 in the

loadbalancer.prop configuration file. The connection-specific rules that

modify IP and MAC addresses should include an instruction (see Rule

Instructions/Action paragraph below) to match the modified packets against

the rules installed by your layer-3 routing application. Since your layer-3

routing application will install rules in the table class variable in the

ShortestPathSwitching class, this instruction should direct packets to the

table defined in this class variable. The modified packet will then be

matched against these rules and forwarded out the appropriate port.

All packets which are not TCP packets destined for a virtual IP, or packets

associated with a connection that has already been assigned to a specific

host, should be send directly the table used by your layer-3 routing

application.

Sending TCP Resets

Once a particular connection has been assigned to a particular host, all

packets for that connection should be directed to that host. However, if no

packets are transmitted for more than 20 seconds (specified by the

IDLE_TIMEOUT constant in the LoadBalancer class), then we want to

remove the rules that perform the rewriting for that particular connection.

Ideally, the 20 second idle period should only occur once a flow has

ended. However, it’s possible that an active TCP flow could also go idle

for some time. If this happens, an entry could timeout prematurely, and the

SDN switch will receive TCP packets destined for the virtual IP for which

it has no connection-specific flow table entry that matches. These packets

will instead match the lower priority rule that sends any TCP packets

destined for the virtual IP to the controller. When the controller receives

these TCP packets, which are not TCP SYN packets, it should construct and

send a TCP reset. You can construct the packet using the classes in the

net.floodlightcontroller.packet package. You can use the

sendPacket(...) method in the SwitchCommands class to send the packet.

Sending ARP Packets

When a client wants to initiate a connection with the virtual IP, it will need

to determine the MAC address associated with the virtual IP using

ARP. The client does not know the IP is virtual, and since it’s not actually

assigned to any host, your SDN application must take responsibility for

replying to these requests.

You can construct an ARP reply packet using the classes in the

net.floodlightcontroller.packet package. You can use the

sendPacket(...) method in the SwitchCommands class to send the

packet.

Rule Instructions/Actions

When a rule should send a packet to the controller, the rule should include

an OFInstructionApplyActions whose set of actions consists of a single

OFActionOutput with OFPort.OFPP_CONTROLLER as the port number.

When a rule should rewrite the destination IP and MAC addresses of a

packet, the rule should include an OFInstructionApplyActions whose

set of actions consists of:

? An OFActionSetField with a field type of

OFOXMFieldType.ETH_DST and the desired MAC address as the

value

? An OFActionSetField with a field type of

OFOXMFieldType.IPV4_DST and the desired IP address as the value

The actions for rewriting the source IP and MAC addresses of a packet are

similar.

When a packet should be processed by the SDN switch based on the rules

installed by your layer-3 routing application, a rule should include an

OFInstructionGotoTable whose table number is the value specified in

the table class variable in the ShortestPathSwitching class.

4.3 Testing and Debugging

You should test your code by issuing web requests (using curl) from a client

host to the virtual IPs.

You can add or remove virtual IPs and hosts by modifying the

loadbalancer.prop file.

To see which packets a host is sending/recieving run:

$ tcpdump -v -n -i hN-eth0

replacing N with the host’s number.

5. Evaluation:

This project is worth 100 points (extra credit not included). You will be graded

on both the completeness and accuracy of your program, as follows:

? Part 3 functionality [70 points].

? Part 4 functionality [25 points]

? Style [5 points]:

1. Coding Style: Well-structured, well documented, clean code, with well

defined interfaces between components. Appropriate use of comments,

clearly identified variables, constants, function names, etc.

2. Assignment Report Layout:

o Assignment report is neatly assembled on 8 1/2 by 11 layout

o Cover page with your name (last name first followed by a comma

then first name), username and section number with a signed

statement of independent effort is included (note: provide a single

report with all team members’ last/first name if your worked on the

project as a team)

o Program and documentation submitted for Assignment #8 are

satisfactory

o File name is correct.

? Part 3 extra credit questions [20 points (10 each)]:

6. What to Submit

a. All of your source code files for part 3 (apps/sps directory) and part 4

(apps/loadbalancer directory).

b. tests.txt/doc - file containing a brief description of your testing and

debugging methods for part 2 and part 4.

c. vulnerabilities.txt/doc – file identifying at least one vulnerability in your

current implementation for each of part 3 and part 4.

d. readme.txt: file containing a thorough description of your design and

implementation for part 3 and 4. Please note that all code that you do not

freshly write for this assignment must be clearly documented in this

readme.txt file.

e. Report document that describes your project briefly, explains your design,

outlines some of the implementation details, and provides as assessment of

what went well and not so well in your project. Problems should be clearly

stated and solution approaches should be clearly documented (i.e., both

current and new features that you implemented). You should also clearly

document any simulation or modeling used in your approach and any

evaluation metrics you used for comparative analysis of the current and new

solutions. The format for your final project report should be similar to the

standard conference paper formats/layouts and should include (at the very

least) sections on Introduction, Related Work, Proposed

Solution/Architecture/Algorithms, Simulation/Implementation, Results,

and Conclusion.

Submissions that partially cover the scope of the examination specification or will

not compile, link, or run once submitted on May 14, 2024 at 11:59 pm ET will be

deemed incomplete and may still receive partial credit.

7. Upload your final project deliverables via NYU Brightspace.

8. Acknowledgements

The code and instructions for this project is partially based on software

packages developed at University of Wisconsin and at Brown University.

Note that the original software packages provided are as follows:

edu.wisc.cs.sdn.apps.loadbalancer and edu.brown.cs.sdn.apps.sps

It is fine to refactor these packages as follows for the purpose of this project:

edu.nyu.cs.sdn.apps.loadbalancer and edu.nyu.cs.sdn.apps.sps

Also note that edu.wisc.cs.sdn.apps.l3routing is not used in this project.

VI. Deliverables

1. Electronic Archive:

Your project submission archive file must be uploaded via NYU Brightspace. The

file must be created and sent by the deadline. After the deadline, the project is late.

The email clock is the official clock.

Your project submission archive file should contain your report file as well as your

program source code packaged as a .jar file. Your report file should include

screenshots that demonstrate that you implemented your own working solutions for

the various parts of the final project. The various documentation files submitted

should be placed in the .jar file in a separate directory called “project

documentation”.

To create the .jar file containing your Java source code (please do not include the

class files), change your working directory to the directory where your Java files

are located and execute the command:

jar cvf DCN-Spring2024-FinalProject-xxx.jar *

where xxx is YOUR FULL STUDENT ID (note: append dash followed by

additional student ID if you worked on the project as a team)

Include the jar file in your project zip file and send the zip file as an email

attachment to the instructor.

You may send questions to the project discussion list ONLY.

2. Report File (to be included in the electronic archive):

PDF of your project report.

The cover page supplied on the next page must be the first page of your project

report. Please fill in the blank area for each field.

NOTE:

The sequence of the electronic report submission is:

1. Cover sheet

2. Assignment Answer Sheet(s)