UDL On-link Scalability

1
UDL On-link Scalability

• Kotaro Kataoka
• Keio University

2
Outline

• How many nodes can a single UDL handle?
• How do we improve on-link scalability?
• Tune parameters on existing protocols
• Provide new systems
• Address Resolution on large scale UDLs

3
Background

• Broadcast Media as Internet Infrastructure
• Huge number of subscribers
• Unidirectional links Feedback BDL
• What will happen there?

4
Definition of Scalability

• Number of nodes which a link can accommodate
• Rate of control traffic against available
  bandwidth
• Control Traffic
• IPv6 Address Auto-configuration (RS, ND)
• Multicast Group Management (MLD)
• Unicast / Multicast Routing Protocols
• Ack / Nack / And more
• Data Traffic
• Many types of traffic

5
Possible Service Traffic (1/1)
ExternalNode
External Node
Router
P2
P1
Internet
P4
Host
Host
Host
Host

P3
P5?
6
Possible Service Traffic (2/2)

1. Multicast from an external (Internet) node to
   subscriber nodes
2. Unicast between a subscriber node and an external
   (Internet) node
3. Multicast from a subscriber node to external
   (Internet) nodes
4. Multicast from a subscriber node to subscriber
   (on-link) nodes
5. Unicast between subscriber (on-link) nodes

Priority
Probability
7
Focus of Research IPv6

• Problem
• Bandwidth consumption on UDL
• Approach / Solution
• Tune back-off timers on ICMPv6
• Proxy
• Filtering Approach
• BDL Approach

8
Problem Analysis

• Evaluate how many hosts a single UDL can handle
  without any tuning / new system on the link
• Scenarios
• Static (stable on changes on the network)
• No node up/down, No node join/leave, No UDL
  up/down
• Dynamic
• Nodes get up/down
• Nodes get join/leave (multicast)
• UDL gets up/down

• How do we evaluate on-link scalability?
• Calculation
• Check parameters from RFCs
• Mathematical Model
• Simulation
• Omnet
• NS2?
• Make by myself?
• Emulation
• Xen?
• Experiment on AI3 UDL

9
Steps

• Step1 Simple Leaf Network (LAN)
• Address Auto-configuration
• Manipulation of Neighbor Cache and Prefix
• Step2 Enable Multicast Services
• Multicast Group Management
• Step3 Enable Routing Protocols
• Unicast / Multiast

10
Related RFCs for Initial Discussion

• RFC4294 IPv6 Node Requirements
• RFC2461 Neighbor Discovery for IP Version 6
  (IPv6)
• RFC2462 IPv6 Stateless Address Autoconfiguration
• RFC2710 Multicast Listerner Discovery
• To simplify the situation
• Scenario for the first step

11
Steps to establish IPv6 communication on the links

• Stateless Address Autoconfiguration
• Link-Local Addresses
• Creation of Link-Local Addresses
• Duplicate Address Detection
• Global Addresses
• Router Solicitation
• Router Advertisement
• Creation of Global Addresses
• (Duplicate Address Detection)

• Maintenance of neighbor cache on each node
• Several Scenarios to examin in a step-by-step
  manner
• Maintenance of prefix on the link
• Router Advertisement

12
Calculation?

• How much does control data flows on the UDL?
• Bandwidth Consumption
• of nodes
• Packet size of each message and frequency

13
Simple Scenario
ExternalNode
External Node
Router
P2

• Every host is communicating only with
  non-link-local nodes
• RAs from a Router
• Neighbor Solicitation to from every host to
  Default Router on expiry of Neighbor Cache and
  its reverse case
• Neighbor Advertisement to from Default Router to
  every host as the answer for Neighbor
  Solicitation and its reverse case

Internet
Host
Host
Host
Host

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Calculation for Simple Scenario

• Total amount of control data which flows on the
  UDL is
• NH Number of Hosts
• LNS Length of Neighbor Solicitation
• LNA Length of Neighbor Advertisement
• LRA Length of Router Advertisement
• TR Time duration during which nodes recognize
  that the other nodes are reachable on the link
  (Default 30 sec)
• IRA Interval of RA (Default 600sec)

15
Methods for Designing Solutions

• Solutions?
• Filtering approach
• Reverse UDL approach
• Evaluation would be done by same method of
  problem analysis

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Filtering Approach
Filtered Neighbor Solicitation for DAD
DAD Proxy
UDL
Router Advertisement with Short Interval
UDL FeedBridge
IP Encapsulater
Router
Neighbor Solicitation for DAD
Neighbor Solicitation for DAD
UDL
Suppressed Router Solicitation
Internet (BDL)
UDLReceiver
Neighbor Solicitation for DAD
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Reverse UDL Approach

• Receiver nodes advertise their BDL IP address
  which are mapped to UDL IP address
• Specific traffics (protocols) go to BDL

Data Band via UDL
UDL Feed
UDL Receivers

Data
Control Band via BDL
Control
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Future Work / Directions

• Have to do many things...
• Define communications models (scenarios) on UDL
• Analyze scalability for other scenarios
• Implement scenarios in the simulator
• Design and Implement the approach to improve
  scalability on simulator
• Move into the real world

19
Comments?
20
Materials
21
What a router has to maintain onan idle network
on a stable link

• Unsolicited (Periodic) Router Advertisement
• 1 per 600sec (Default MAX Interval)
• Solicited (On-demand) Router Advertisement
• Active network only

22
???????

• ????
• ???analysis framework???

23
Road Map

• ?????
• ????????
• ???????????

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Control Traffic on an Active (non-link-local
only) Network on a Stable Link

• Active (non-link-local only)?
• Every host is communicating only with
  non-link-local nodes
• RAs from a Router
• Neighbor Solicitation to from every host to
  Default Router on expiry of Neighbor Cache and
  its reverse case
• Neighbor Advertisement to from Default Router to
  every host as the answer for Neighbor
  Solicitation and its reverse case

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• For neighboring routers, reachability means that
  packets sent by a node's IP layer are delivered
  to the router's IP layer, and the router is
  indeed forwarding packets (i.e., it is configured
  as a router, not a host)
• For hosts, reachability means that packets sent
  by a node's IP layer are delivered to the
  neighbor host's IP layer

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• ?????????
• ?????????????
• ??????
• ??????
• ??????
• ????IP????????????

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RFCs for IPv6 Infrastructure

• Internet Protocol Version 6
• RFC 2460
• Neighbor Discovery for IPv6 RFC2461
• ICMP for the Internet Protocol Version 6 (IPv6) -
  RFC 2463
• Multicast Listener Discovery (MLD) for IPv6 - RFC
  2710 .....

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Sirokuma-sans comment

• Two different themes
• UDL scalability (ARP, Broadcast Protocols could
  work or not with many hosts?)
• Time from network down to recovery
• Recovery time depens on many technologies from
  L2L3
• Terrestrial performance
• Check OUR SITUATION ONLY
• Use Starbet

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On-going work

• Omnet Tutorial
• IP IPv6 Suite Install and start to touch
• What I want to present at AI3 Meeting
• Simple calculation on link scalability
• Simple simulation of large-scale ethernet
• BCMA with delay tuning to emulate UDL
• Narrow band
• Long delay
• IPv6 nodes on UDL

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??

• ???????????evaluate???????????????????
• ?????
• Estimate number of packet
• Expire time of neighbor cache on each IPv6 node
• RA interval
• ???
• On-link ??????????????
• ???????????Number of node dependent???independent?
  ??
• ICMPv6 Routing Protocol
• ?????????????
• Hello Interval??
• Timer?Implementation Dependent????RFC????????????
• ARP Cache?30?
• Adhoc?Method????????????????????

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Hosts / Routers

• Hosts need
• Maintain Neighbor Cache

• Routers need to
• Maintain Neighbor Cache
• Issue Router Advertisement

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UDL??????????

• Neighbor Discovery
• Address Autoconfiguration

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• 10. PROTOCOL CONSTANTS
• Router constants
• MAX_INITIAL_RTR_ADVERT_INTERVAL 16
  seconds
• MAX_INITIAL_RTR_ADVERTISEMENTS 3
  transmissions
• MAX_FINAL_RTR_ADVERTISEMENTS 3
  transmissions
• MIN_DELAY_BETWEEN_RAS 3
  seconds
• MAX_RA_DELAY_TIME .5
  seconds
• Host constants
• MAX_RTR_SOLICITATION_DELAY 1
  second

• Node constants
• MAX_MULTICAST_SOLICIT 3
  transmissions
• MAX_UNICAST_SOLICIT 3
  transmissions
• MAX_ANYCAST_DELAY_TIME 1
  second
• MAX_NEIGHBOR_ADVERTISEMENT 3
  transmissions
• REACHABLE_TIME 30,000
  milliseconds
• RETRANS_TIMER 1,000
  milliseconds
• DELAY_FIRST_PROBE_TIME 5
  seconds
• MIN_RANDOM_FACTOR .5
• MAX_RANDOM_FACTOR 1.5

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Scenarios

• Node definition (Make problems for each type
  clear)
• Router (Host Forwarding capability)
• Host (End node)
• Router Host
• Type of Traffic (Services) on UDL
• See next page

35
What nodes have to maintain onan idle network on
a stable link

• Neighbor Cache
• Life time for each cache entry is 30sec
• Send Neighbor Solicitation to Default Router on
  expiry
• Send Neighbor Advertisement to Default Router on
  request
• Destination Cache
• Maybe vacant on an idle network
• As a result of communication, this cache is
  maintained
• Prefix List
• Learn from Router Advertisement
• Default Router List
• Learn from Router Advertisement
• Associated with Neighbor Cache

36
Very simple scenario

• Stable Link
• No New Host
• No Packet Loss
• No Link Down / UP
• Traffic
• Idle network (no traffic) as first step
• Active network as second step (Multicast from
  Router)?
• Some conditions affect behavior of hosts

37
Calculation?

• How much does control data flows on the UDL?
• Bandwidth Consumption
• of nodes
• duration
• Packet size and frequency
• Steady State
• Neigbor cache????30????
• Transient State
• Node UP/DOWN
• ?????????
• 10??????1?Up/Down??2????
• Generalization???