US 7113485

Patent Overview — US 7,113,485 B2

Title: Latency evaluation in a ring network

Source: https://patents.google.com/patent/US7113485/en

Bibliographic data (from the supplied text): Application number US09/947,183; filed 2001-09-04; priority date 2001-09-04; published as US20030048754A1 on 2003-03-13; granted as US7113485B2 on 2006-09-26. Inventor: Leon Bruckman. Original assignee: Orckit Corrigent Ltd; current assignee listed as Corrigent Corp. Legal status listed as "Expired - Lifetime," with adjusted expiration 2024-07-08. Classifications include H04L41/5003 (managing SLA/QoS interaction), H04L43/0858 (one-way delays), and H04L43/0864 (round trip delays).

Purpose: The patent relates to network communication systems and protocols, specifically latency measurement in packet-switched networks, particularly ring networks. The problem addressed: a service provider committing to a service level agreement (SLA) with latency-related parameters must be able to monitor latency to verify compliance, and existing round-trip methods include the destination node's processing time, contaminating the measurement.

Plain-language scope: The described protocol defines a latency measurement packet (LMP). An originating node sends a LMP, recording the time of transmission and, preferably, a serial number (SN), enabling identification of each LMP on return and latency determination based solely on information in the packet—permitting multiple, frequent, precise measurements even at overlapping times. The LMP may also indicate a class of service (CoS), so nodes transmit it at that priority, giving a CoS-specific measurement for each of multiple CoS levels. A peer node records its receipt time using its own (unsynchronized) clock, then records its transmission time on the return ring, letting the originating node compute turnaround time as the difference. The originating node subtracts that turnaround time from its own total round-trip time to find net round-trip latency. The text states the protocol is geared to bidirectional ring networks but may apply, mutatis mutandis, to other topologies.

Not established by the excerpt: The full claims and their exact scope, the detailed embodiments, the complete list of cited prior art, and the omitted portion of the description are not available in the supplied text.