JinHyeock Choi, DongYun Shin hppt:// Fast Router Discovery with L2 Support draft-jinchoi-dna-frd-01.txt

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.

Key Idea Point of Attachment (PoA) – The link endpoint on the link, such as Access Point (AP) or Base Station (BS), where a host may be connected. While a router doesn’t 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”.

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 MAC address or 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".

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

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.

RA Caching methods Manual Configuration Scanning MICS (Media Independent Comment Service)

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.

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

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

FRD Implementation Implemented the FRD code on Linux OS (Kernel ) – 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 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

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.

1. PC AP with WLAN interface has FRD module. AP MN RA 2. AP scans incoming packets to cache an RA. FRD Test Scenario AR

1. PC AP with WLAN interface has FRD module. AP MN 3. At time T[0], MN establishes a new link layer connection with AP. 2. AP scans incoming packets to cache an RA. 4. After L2 association, AP immediately sends the cached RA in L2 unicast frame FRD Test Scenario AR RA

1. PC AP with WLAN interface has FRD module. 3. At time T[0], MN establishes a new link layer connection with AP. 2. AP scans incoming packets to cache an RA. 4. After L2 association, AP immediately sends the cached RA in L2 unicast frame FRD Test Scenario 5. At time T[1], MN receives the cached RA. 6. We measure the DNA delay, T[1] – T[0]. 7. Measured value of T[1] – T[0]. Min: 1.1ms Max: 1.8ms Average 1.3ms AP MN AR RA

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

Internet 0. There is an RA which can properly represent link identity, for example an RA with LinkID. AR AP RA LinkID RA Triggering, rough sketch MN 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.

Internet 0. There is an RA which can properly represent link identity, for example an RA with LinkID. AR AP RA Triggering, rough sketch MN 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. RA LinkID

Internet 0. There is an RA which can properly represent link identity, for example an RA with LinkID. AR AP RA Triggering, rough sketch MN 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. RA LinkID 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).

Internet 0. There is an RA which can properly represent link identity, for example an RA with LinkID. AR AP RA Triggering, rough sketch MN 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. RA LinkID 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).

0. There is an RA which can properly represent link identity, for example an RA with LinkID. Internet AR AP RA LinkID RA Proxying, rough sketch

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

Internet AR AP 1. AP caches an RA with LinkID, either manually or dynamically. RA LinkID MN 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. 0. There is an RA which can properly represent link identity, for example an RA with LinkID. 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). RA Proxying, rough sketch

Internet AR AP 1. AP caches an RA with LinkID, either manually or dynamically. RA LinkID MN 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. RA Proxying, rough sketch 0. There is an RA which can properly represent link identity, for example an RA with LinkID. 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).

Delay – RFC 2461 without Link UP AR AP MN 6. MN receives RA and discovers new subnet. 1. MN arrives and sends Association Request 3. AP sends Association Response. 2. AP receives Association Request. 4. MN receives Association Response and association is made. 5. AR sends Unsolicited RA AR sends RA periodically

Delay – RFC 2461 with Link UP AR AP MN 8. MN receives RA and discovers new subnet. 1. MN arrives and sends Association Request 3. AP sends Association Response. 2. AP receives Association Request. 4. MN receives Association Response and association is made. 7. AR sends RA after Random delay 5. MN sends RS after Random delay. 6. AR receives RS

AR AP MN 1. MN arrives and sends Association Request 3. AP sends Association Response 2. AP receives Association Request. 4. AP send stored RA. 4. MN receives Association Response and association is made. 5. MN receives RA and discovers new subnet. Delay – FRD

Continuous Scanning It may cost too much to execute Scanning continuously. RA arrival

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.

Effect of T value Scan Start Scan Stop Scan Start Scan Stop Scan Start Scan Stop RA arrival With T value, We can decrease Scanning execution time. We assume a network administrator selects appropriate T value. TT