Projects Overview Andrea Forte

1
Projects Overview Andrea Forte

• Fast L3 handoff
• Passive DAD (pDAD)
• Cooperative Roaming (CR)
• Highly congested IEEE 802.11 networks
  Measurements and Analysis

2
Fast L3 Handoff

• We optimize the IP address acquisition time as
  follows
• Subnet Discovery
• Checking Cache for a valid IP
• Temp_IP (Cache miss) ?The client picks a
  candidate IP using particular heuristics.
• SIP re-invite ?The CN will update its session
  with the TEMP_IP.
• Normal DHCP procedure to acquire the final IP
• SIP re-invite ? The CN will update its session
  with the final IP.

3
Fast L3 Handoff - Results
4
Passive DAD - Architecture
Address Usage Collector (AUC)
DHCP server
TCP Connection
Broadcast-ARP-DHCP
Router/Relay Agent
SUBNET

• AUC builds DUIDMAC pair table (DHCP traffic
  only).
• AUC builds IPMAC pair table (broadcast and ARP
  traffic).
• The AUC sends a packet to the DHCP server when
• a new pair IPMAC is added to the table
• a potential duplicate address has been detected
• a potential unauthorized IP has been detected
• DHCP server checks if the pair is correct or not
  and it records the IP address as in use. (DHCP
  has the final decision!)

5
Cooperative Roaming (CR)

• Stations can cooperate and share information
  about the network (topology, services).
• Stations can cooperate and help each other in
  common tasks such as IP address acquisition.
• Stations can help each other during the
  authentication process without sharing sensitive
  information, maintaining privacy and security.
• Stations can also cooperate for application-layer
  mobility and load balancing.

6
CR Results (1/2)
7
CR Results (2/2)
8
Wireless measurements in highly congested 802.11
networks

• IETF meeting in Dallas (IETF-65)
• Three days of measurements (8GB of data).
• 400500 people in one room (plenary).
• IEEE 802.11a/b
• Multiple APs on same channel.
• Congestion analysis (throughput, retries, ARF),
  handoff analysis (Apple vs. others), unusual
  behaviors (broadcast feedback), load balancing
  (num. of clients vs. bandwidth).

9
Projects OverviewKundan Singh

• P2P-SIP using external DHT
• Thread and event models
• Conference server scalability

10
SIP-using-P2PP2P-SIP using an external
distributed hash table (DHT)

• Data vs service modes
• Data treat DHT as data storage using
  put/get/remove
• Service join DHT to provide registrar/presence
  service using join/leave/lookup
• Logical operations
• Contact management
• put (user id, signed contact)
• Cryptographic key storage
• User certificates and private configurations
• Presence
• put (subscribee id, signed encrypted subscriber
  id)
• Composition needs service model
• Offline message
• put (recipient, signed encrypted message)
• NAT and firewall traversal
• STUN and TURN server discovery needs service model

Proposed an XML-based data format
11
SIP-using-P2PImplementation in SIPc with the
help of Xiaotao Wu

• OpenDHT
• Trusted nodes
• Robust
• Fast enough (lt1s)
• Identity protection
• Certificate-based
• SIP id email
• P2P for
• Calls, IM, presence, offline message, STUN
  server discovery and name search
• P2P clients better than proxies
• Less DHT calls
• OpenDHT quota for fairness imposes limit on
  proxies

Should this be made open source?
12
SIP proxy performanceEffect of software
architecture and multi-processor hardware
Both Pentium and Sparc took approx 2 MHz CPU
cycles per call/s on single-processor

• Calls/s for stateless proxy, UDP, no DNS, 6
  msg/call

Better performance as this includes mempool
changes
Calls/s for stateful proxy, UDP, no DNS, 8
msg/call
Software architecture further improves
performance S3P3 can support 16 million BHCA
13
Should sipd use 2-stage thread pool architecture?
Not much concurrency in stateful mode needs more
investigation
14
SIP conference server PerformanceFor G.711 audio
mixing on a 3 GHz Pentium 4 with 1 GB memory

• About 480 participants in a single conference
  with one active speaker (CPU is bottleneck)
• About 40 four-party conferences, each with one
  active speaker (CPU is bottleneck)
• Memory usage 20 kB/participant
• Mixer delay less than 20 ms
• Increasing the packetization interval to 40 ms
  improves performance to 700 participants, but
  also increases mixer delay
• Both Pentium and Sparc take about 6
  MHz/participant

15
Cascaded conference server
SIP REFER message is used to create cascading
?
?
?
?
?
?
I measured the CPU usage for two cascaded
servers supports about 1000 participants in a
single conference. The cascaded architecture
scales to tens of thousands of participants.
16
Projects OverviewXiaotao Wu

• CUTE (Columbia University Telecommunication
  service Editor)
• GUI-based service creation tool to help
  inexperienced users to create services
• Service learning and service management
• Service learning
• Service risk management
• Handling feature interactions

17
CUTE (Columbia University Telecommunication
service Editor)
18
Survey on CUTE

• Evaluating how likely an end user can create
  telecommunication services by himself and how
  useful and friendly CUTE is
• http//www.surveymonkey.com/s.asp?u909901973365

19
Service learning and service risks

• Causal relationship between call information and
  call decisions
• Decision tree induction
• Incremental Tree Induction algorithm
• Service risk management
• Identify Lose connection, privacy, money,
  attention
• Analyze Possibility, impact, overall risk
• Resolve Change communication methods, transfer,
  reduce overall risk
• Contingency plan

20
Feature interaction handling

• Tree merging

Incoming call
Incoming call
Incoming call
If time is between 1000AM and 1100AM
If address is hgs
If address is hgs
If time is between 1000AM and 1100AM


accept
accept
accept
reject
Forward to conf
Forward to conf
reject
Take actions from both scripts. Simply setting
precedence rules cannot work.
21
Service management