Design of a Home Network

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Design of a Home Network

• Rajesh Rajamani
• (raj_at_cs.wisc.edu)

2
Home networking - Applications

• Computer Interconnection
• Control

3
Home networking technologies Physical layer

• Phoneline
• Powerline
• Ethernet
• Wireless

4
We wanted

• A Dynamic network
• Configuration
• Sharing resources
• Maintanence
• Control - from anywhere, anytime

5
Design issues

• System Software
• Hardware
• Integrating hardware with software

6
Connection Technology

• Jini
• UPnP

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Choices Operating system

• Linux
• Unix variants
• Windows
• Guiding principle - Source availability,
  Synopsys network

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Choices - Hardware

• Verilog - Popular in North America
• VHDL - Popular in Europe
• Guiding principle - Time to Market

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Verification
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Co-verification using Eaglei

• Link models
• Instruction set simulator (ISS)
• Live Target

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Link model

• Full visibility into the s/w execution process
• Can test functionality of the design

GenericVSPRead32()
1. Function call
Eaglei
2. Reaches VSP core thru eaglei
VSP
Memory /registers
3. I/O bound instructions are executed
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ISS model

• Full visibility into the processor and can
  execute assembly instrs
• Good for debugging device drivers

Actual Instructions
BFM
ISS
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Finally, each device
Application using Jini
JVM
Java Native Interface
Eaglei
Verilog Model
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The Network
WWW
CLIENT
SERVLET
The Client clicks on the link leading to his URL
requesting a service
1. Ask for the service
Jini Lookup
2. Get the service proxy
The services register their proxies with the
lookup service, which is queried by the servlet
for servicing the request from the client.
3. Interact with device
DEVICES
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Jini Connection Technology

• Java centric, distributed system designed for
  simplicity, flexibility and federation
• Members of the federation agree on basic notions
  of trust, administration, identification and
  policy
• Components - Services, Infrastructure and
  programming model

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Components
Infrastructure Programming model Services
JVM, RMI, Discovery/Join, Lookup service, Java security Java API, Leasing, Transactions, events Printer, Refrigerator,
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Key concepts

• Lookup Service - Central bootstrapping mechanism
  for the system helps find and resolve available
  services service added to a lookup service by a
  pair of protocols - Discovery and Join
• Leasing - Grant of guaranteed services over a
  time period
• Security JDK 1.2 Security model

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Key concepts

• Service object contains the Java programming
  language interface for the service, including the
  methods that users and applications will invoke
  to execute the service along with any other
  descriptive attributes.

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Lookup Service
Lookup Service
Lookups proxy
Lookups proxy
Service Provider
Service Provider
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Lookup Service
Lookups proxy
DISCOVERY
Service Provider
Lookups proxy
1. Get Lookups proxy from the lookup
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Lookup Service
Lookups proxy
Service Object
JOIN
Service Attributes
Service Provider
Lookups proxy
2. Register service object with lookup
1. Get Lookups proxy from the lookup
Service Object
Service Attributes
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Lookup Service
Service Object
Service Attributes
1b. Query the Lookup service
2b. Gets Service Proxy
Service Provider
Client
Service Object
Service Attributes
3b. Interact with service
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Discovery and Join

• Discovery - Process by which Jini applications
  find the lookup services that serve their
  communities.
• Two forms - Serendipitous and hard wired.
• Service initiated discovery, Lookup initiated
  discovery and direct discovery

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Multicast Request (Service Initiated Discovery
Discoverer
Lookup Service
1. Request Message (sent via UDP Multicast) IP
Address - 224.0.1.85 port4160 via UDP
Multicast) IP Address - 224.0.1.85 port4160
2. Response Message Service Proxy sent (Sent
via TCP unicast)
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Protocol Characteristics

• Multicast UDP to IP - 224.0.1.85, port 4160
• Interval - 5 secs. Seven rounds of multicast
  requests is recommended
• Switch over to listening for announcements
• Multicast Packet length never to exceed 512 bytes

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Multicast Announcement (Lookup initiated
discovery)
Discoverer
Lookup Service
1. Announcements (sent via UDP Multicast) IP
Address - 224.0.1.84 port4160
2. Request Message (sent via TCP unicast)
3. Response Message (Sent via TCP unicast)
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Protocol Characteristics

• Multicast UDP to IP - 224.0.1.84, port 4160
• Interval - 120 secs.
• Multicast Packet length never to exceed 512
  bytes.

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Unicast Discovery (Direct Discovery)
Discoverer
Lookup Service
1. Request Message (sent via TCP Unicast)
2. Response Message (Sent via TCP
unicast, connects to 4160)
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Join Protocol

• Registering with the lookup service
• The service object for the service is loaded into
  the lookup service
• Get a lease - a period of time during which the
  lease grantor ensures that the holder of the
  lease will have access to some resource

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Lookup Service
Join Protocol
Service Object
Service Object
Service Attributes
Service Attributes
Service Provider
Client
Client
Service Object
Service Attributes
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Lookup Service Specification

• Programs that need a particular type of service
  can use the lookup service to find an instance.
• Lookup service may provide a set of methods to
  enable incremental exploration of the collection.
• Users are allowed to explore a collection of
  items down each of the major axes attribute
  value and service type.

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Lookup Service
Lookup Service
Service Object
Service Attributes
1. Query the Lookup service
2. Gets Service Proxy
Service Provider
Client
Service Object
Service Attributes
3. Interact with service
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Device Architecture Alternatives

• Device with computing power, memory, full JVM
• Devices with specialized JVMs - need not include
  security manager, code verifier, or a number of
  other components
• Clustering of devices with a Shared Virtual
  Machine

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Full Jini Capable Device
Service client
Service Provider
Hardware Implementation
Client
Private Protocol
Proxy
JVM
Network
Communication via RMI protocol
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Clustering of devices with a Jini capable proxy
on the network
Service client
Network Proxy
Client
Proxy
JVM
Private Protocol
Network
Communication via RMI protocol
Dev 1
Dev 2
Dev 3
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Conclusions

• Encouraging
• Easy to put together
• Discouraging
• Bad response time
• Jini JVM ( OS) is very heavy

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The Network
WWW
CLIENT
SERVLET
The Client clicks on the link leading to his URL
requesting a service
1. Ask for the service
Jini Lookup
2. Get the service proxy
The services register their proxies with the
lookup service, which is queried by the servlet
for servicing the request from the client.
3. Interact with device
Printer
Refrigerator
SmartPhone
DEVICES
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Finally, each device
Application using Jini
JVM
Java Native Interface
Eaglei
Verilog Model
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Danger if proxy overrides deserialization
method

• public class HostileFileClassifier2 implements
  FileClassifier,
• java.io.Externalizable
• public void readExternal(java.io.ObjectInput
  in)
• if (java.io.File.pathSeparator.equals("/")
  )
• // Unix - don't uncomment the next
  line!
• // Runtime.getRuntime().exec("/bin/rm
  -rf /")
• else
• // DOS - don't uncomment the next
  line!
• // Runtime.getRuntime().exec("format
  c /u")
• public void writeExternal(java.io.ObjectOutput
  out)
• throws java.io.IOException
• out.writeObject(this)
• // HostileFileClassifier2

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Security - Service

• Specify Policy File as command line argument
• java Djava.security.policyfilename
• Sample Policy File
• grant
• permission net.jini.discovery.DiscoveryPermiss
  ion printers"
• // multicast request address
• permission java.net.SocketPermission
  "224.0.1.85", "connect,accept"
• // multicast announcement address
• permission java.net.SocketPermission
  "224.0.1.84", "connect,accept"
• // RMI connections
• permission java.net.SocketPermission
  ".cs.wisc.edu1024-", "connect,accept"
• permission java.net.SocketPermission
  "130.102.176.2491024-", "connect,accept"
• permission java.net.SocketPermission
  "127.0.0.11024-", "connect,accept"

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Security - Client

• grant
• permission net.jini.discovery.DiscoveryPermiss
  ion ""
• // multicast request address
• permission java.net.SocketPermission
  "224.0.1.85", "connect,accept"
• // multicast announcement address
• permission java.net.SocketPermission
  "224.0.1.84", "connect,accept"
• // RMI connections - DANGER
• // HTTP connections - this is where external
  code may come in - careful!!!
• permission java.net.SocketPermission
  "127.0.0.11024-", "connect,accept"
• permission java.net.SocketPermission
  ".cs.wisc.edu1024-", "connect,accept"
• permission java.net.SocketPermission
  "130.102.176.2491024-", "connect,accept"
• // HTTP connections - this is where external
  code may come in - careful!!!
• permission java.net.SocketPermission
  "127.0.0.180", "connect,accept"
• permission java.net.SocketPermission
  ".cs.wisc.edu80", "connect,accept"

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Bluetooth v/s Jini

• Bluetooth - transport layer, allowing devices to
  find each other, to form a local network. It does
  not say what they do then
• Jini - application layer, allowing services and
  clients to use each other
• Complementary

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Co-verification
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Clustering of multiple devices (physical option)
Service client
Service Provider
Dev 1
Dev 2
Dev 3
Client
Private Protocol
Proxy
JVM
Network
Communication via RMI protocol
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Leasing Characteristics

• A lease is a period of time during which the
  lease grantor ensures that the holder of the
  lease will have access to some resource
• A lease holder can request that a lease be
  renewed. If not renewed, the lease simply expires