IPng%20Workinging%20Group%20April

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Fast Router Discovery with L2 Support draft-jinch
oi-dna-frd-01.txt
JinHyeock Choi, DongYun Shin hppt//www.diffeo.c
om/FRD.ppt
2
Background

• G2
• When upper-layer protocol sessions are being
  supported, DNA schemes should detect the identity
  of an attached link rapidly, with minimal latency
  lest there should be a service disruption.
• For fast DNA, a host needs to quickly receive a
  suitable RA upon establishing a new link-layer
  connection.
• This draft present a way to deliver an RA to a
  host with minimal latency upon network
  attachment.

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Key Idea

• Point of Attachment (PoA)
• The link endpoint on the link, such as 802.11
  Access Point (AP) or 802.16 Base Station (BS),
  where a host may be connected.
• While a router doesnt perceive the presence of a
  new host, usually L2 entity, PoA (Point of
  Attachment), does.
• PoA may either 1
• trigger an AR (Access Router) to immediately send
  an RA RA Triggering or
• send such an RA for itself RA Proxying.

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Overview

• When a host establishes a link-layer connection,
  in the process, an L2 entity, PoA (Point of
  Attachment), can detect the new attachment and
  get the necessary information to deliver an
  unicast L2 frame to the host, such as 802.11 MAC
  address or 802.16 CID (Connection Identifier).
• The PoA may forward the information to an AR
  (Access Router) and trigger the AR to immediately
  send in unicast a suitable RA.
• Or the PoA itself may cache such an RA beforehand
  and deliver the cached RA to the host in unicast
  upon network attachment
• In this draft, we refer the first scheme "RA
  Triggering" and the second "RA Proxying".

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RA Triggering Operation

• PoA and AR in one box
• Link UP Event Notification
• PoA and AR in separate boxes
• MIES (Media Independent Event Service)
• RS by PoA

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RA Proxing Operation

• RA Caching
• PoA gets a suitable RA and stores it.
• RA Delivery
• As soon as a host established link-layer
  connection with a PoA, it immediately sends a
  stored RA to the host in unicast.

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RA Caching methods

• Manual Configuration
• Scanning
• MICS (Media Independent Comment Service)

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Summary

• This draft present a way for a host to receive a
  suitable RA with minimum latency.
• RA proxying delivers the RA in the earliest
  possible time.
• This draft provides an useful DNA scheme with
  some constraints.
• The scheme is suitable for network initiated DNA.
  
• The scheme is Mobile/ Cellular network friendly.
• The scheme depends on link-layer support.
• The scheme works very well in certain
  environments, especially Mobile/ Cellular network
  but may not generally applicable to all networks.
  
• We also plan to advance this scheme in WIMAX and
  IEEE.
• We ask WG to accept this draft as a WG item
• to facilitate its adoption to other standard
  bodies
• to help the scheme to be deployed in mobile/
  cellular network.

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Appendix

• FRD Test Results
• RA Triggering, rough sketch
• RA Proxying, rough sketch
• Rate Control
• Performance Evaluation

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FRD (Fast Router Discovery) Implementation
Test Result
HeeJin Jang
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FRD Implementation

• Implemented the FRD code on Linux OS (Kernel
  2.4.20)
• RA Proxying with Scanning
• AP side
• We adopted the PCI-type card to implement an AP
  (Access Point) on a Linux Box (PC)
• We modified its driver module for FRD
• Part 1 Catch the RA from upper layer and cache
  it in the buffer.
• Part 2 Deliver the cached RA to an MN in
  unicast 802.11 frame right after L2 association
• No. of code lines 31 lines
• Test Results
• We measured the time from L2 association to RA
  arrival with Ethereal
• Average 1.3 ms
• Maximum 1.8 ms
• Minimum 1.1 ms

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FRD Operation

1. We implemented FRD module on drives modules of
   netgear AP.
2. FRD module caches a suitable RA with Scanning.
3. When an MN is attached, it sends Association
   Request message.
4. FRD module extracts the MN's MAC address from the
   the Association Request message.
5. FRD module combines the MN's MAC address with the
   cached RA to make an unicast L2 frame.
6. FRD module sends the unicast L2 frame to the MN.
7. The MN receives the cached RA (in the unicast L2
   frame) in average 1.3 ms after L2 association is
   made.

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FRD Test Scenario
1. PC AP with WLAN interface has FRD module.
2. AP scans incoming packets to cache an RA.
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FRD Test Scenario
1. PC AP with WLAN interface has FRD module.
2. AP scans incoming packets to cache an RA.
3. At time T0, MN establishes a new link layer
connection with AP.
4. After L2 association, AP immediately sends the
cached RA in L2 unicast frame
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FRD Test Scenario
1. PC AP with WLAN interface has FRD module.
2. AP scans incoming packets to cache an RA.
3. At time T0, MN establishes a new link layer
connection with AP.
4. After L2 association, AP immediately sends the
cached RA in L2 unicast frame
5. At time T1, MN receives the cached RA.
6. We measure the DNA delay, T1 T0.
7. Measured value of T1 T0. Min
1.1ms Max 1.8ms Average 1.3ms
16

• We gratefully acknowledge the generous
  assistance we received from Surekha Biruduraju
  for implementing and testing FRD scheme.

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RA Triggering, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. MN moves in and establishes a link-layer
connection (association) with AP.
2. AP module deliver Link UP Event Notification
to AR module.
2. AR module immediately sends a suitable RA to
MN in unicast.


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RA Triggering, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. MN moves in and establishes a link-layer
connection (association) with AP.
2. AP module deliver Link UP Event Notification
to AR module.
2. AR module immediately sends a suitable RA to
MN in unicast.


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RA Triggering, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. MN moves in and establishes a link-layer
connection (association) with AP.
2. AP module deliver Link UP Event Notification
to AR module.
3. AR module immediately sends a suitable RA to
MN in unicast.
4. With LinkID, MN determines whether it remains
at the same link or not.


5. In case of a link change, MN initiates a new
IP configuration with the information in the RA (
Router address, prefix et cetra).
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RA Triggering, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. MN moves in and establishes a link-layer
connection (association) with AP.
2. AP module deliver Link UP Event Notification
to AR module.
3. AR module immediately sends a suitable RA to
MN in unicast.
4. With LinkID, MN determines whether it remains
at the same link or not.


5. In case of a link change, MN initiates a new
IP configuration with the information in the RA (
Router address, prefix et cetra).
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RA Proxying, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.



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RA Proxying, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. AP caches an RA with LinkID, either manually
or dynamically.
2. MN moves in and establishes a link-layer
connection (association) with AP.



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RA Proxying, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. AP caches an RA with LinkID, either manually
or dynamically.
2. MN moves in and establishes a link-layer
connection (association) with AP.
3. As soon as association is completed, AP
immediately sends the cached RA to MN in unicast.
4. With LinkID, MN determines whether it remains
at the same link or not.



5. In case of a link change, MN initiates a new
IP configuration with the information in the RA (
Router address, prefix et cetra).
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RA Proxying, rough sketch
0. There is an RA which can properly represent
link identity, for example an RA with LinkID.
1. AP caches an RA with LinkID, either manually
or dynamically.
2. MN moves in and establishes a link-layer
connection (association) with AP.
3. As soon as association is completed, AP
immediately sends the cached RA to MN in unicast.
4. With LinkID, MN determines whether it remains
at the same link or not.



5. In case of a link change, MN initiates a new
IP configuration with the information in the RA (
Router address, prefix et cetra).
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Delay RFC 2461 without Link UP
AR sends RA periodically
AR
AP
MN
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Delay RFC 2461 with Link UP
AR
AP
MN
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Delay FRD
AR
AP
MN
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Continuous Scanning
It may cost too much to execute Scanning
continuously.
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Rate Control

• Execute Scanning in regular interval.
• It may cost too much to execute Scanning
  continuously.
• For this we set time value T.
• AP execute Scanning in every T time.
• If we set T as 0, scanning is executed
  continuously.

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Effect of T value
With T value, We can decrease Scanning execution
time. We assume a network administrator selects
appropriate T value.