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Browse Prior Art Database

Dynamic Internet Adaptation Based on a Measured Connection Speed

IP.com Disclosure Number: IPCOM000014146D
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Abstract

Disclosed is a method allowing Internet content servers and proxy servers to estimate the connection speed of Internet devices so that the content of a transmission can be dynamically adapted to suit the actual data link speed. This method primarily uses the ECHO_REQUEST/ECHO_REPLY feature of the of the ICMP protocol, which is part of the IP (Internet Protocol),to measure the elapsed time of an end-to-end delay between two Internet hosts. This elapsed time can be measured repeatedly, with large and small packets, with data which is compressible or incompressible using network protocols, and with varying time intervals between requests. The TIMESTAMP_REQUEST/TIMESTAMP_REPLY feature of the ICMP protocol may be used as well. The most significant delay to be measured by this method is the transmission delay, associated with the time needed to transmit a bit of information over a link, which is typically orders of magnitude greater than the propagation delay, the second most significant delay. Other delays, which are measured if they are present and significant, include delays associated with packetization, admission and playout, routing and switching, and queuing. In a prevalent topology, an Internet device is connected to a Network Service Provider (NSP) point of presence (POP) within 4 to 40 kilometers, with the connection being made using existing dial- up wired or wireless connections having speeds of 64 kbps or lower. If the distance between the device and the POP is greatly increased due to movement of a mobile device or of a low-earth-orbit satellite providing the POP, the connection to the device is switched to another POP. A web browser provides access to content through an HTTP caching proxy server located at or near the POP, with an uncongested connection to the POP having a speed of 1 Mbps or higher. In this prevalent topology, this method is implemented entirely in the caching proxy server. If there is no proxy server, this method is implemented in the content server. When the proxy or content server determines that a new device is using its service, obtains the IP address (IPA) of the device and adds it to a stored table including the current estimated average connection speed (CS), the previously measured connection speed (PS), a time stamp field filled with the last time a connection speed was measured on this device (TS). The values of CS and PS are initially set as 0. Next, a connection speed is measured by issuing an ECHO_REQUEST and measuring the time (T) between this request and receiving a corresponding ECHO_REPLY packet. The ECHO_REQUEST is sent, for example, with an incompressible data field of S bytes, preferably with S 200. Then, an estimated connection speed (C) is calculated using equation 1).

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Dynamic Internet Adaptation Based on a Measured Connection Speed

Disclosed is a method allowing Internet content servers and proxy servers to estimate the connection speed of Internet devices so that the content of a transmission can be dynamically adapted to suit the actual data link speed. This method primarily uses the ECHO_REQUEST/ECHO_REPLY feature of the of the ICMP protocol, which is part of the IP (Internet Protocol),to measure the elapsed time of an end-to-end delay between two Internet hosts. This elapsed time can be measured repeatedly, with large and small packets, with data which is compressible or incompressible using network protocols, and with varying time intervals between requests. The TIMESTAMP_REQUEST/TIMESTAMP_REPLY feature of the ICMP protocol may be used as well.

The most significant delay to be measured by this method is the transmission delay, associated with the time needed to transmit a bit of information over a link, which is typically orders of magnitude greater than the propagation delay, the second most significant delay. Other delays, which are measured if they are present and significant, include delays associated with packetization, admission and playout, routing and switching, and queuing.

In a prevalent topology, an Internet device is connected to a Network Service Provider (NSP) point of presence (POP) within 4 to 40 kilometers, with the connection being made using existing dial- up wired or wireless connections having speeds of 64 kbps or lower. If the distance between the device and the POP is greatly increased due to movement of a mobile device or of a low-earth-orbit satellite providing the POP, the connection to the device is switched to another POP. A web browser provides access to content through an HTTP caching proxy server located at or near the POP, with an uncongested connection to the POP having a speed of 1 Mbps or higher.

In this prevalent topology, this method is implemented entirely in the caching proxy server. If there is no proxy server, this method is implemented in the content server. When the proxy or content server determines that a new device is using its service, obtains the IP address (IPA) of the device and adds it to a stored table including the current estimated average connection speed (CS), the previously measured connection speed (PS), a time stamp field filled with the last time a connection speed was measured on this device (TS). The values of CS and PS are initially set as 0. Next, a connection speed is measured by issuing an ECHO_REQUEST and measuring the time (T) between this request and receiving a corresponding ECHO_REPLY packet. The ECHO_REQUEST is sent, for example, with an incompressible data field of S bytes, preferably with S > 200. Then, an estimated connection speed (C) is calculated using equation 1).

A timeout period (TO) is preferably set for receiving the ECHO_REQUEST to be the smaller of 3 sec., or if a value for PS is available, according to eq...