Methods And Systems For Providing Quality Of Service In Packet-Based Core Transport Networks

• US 20080037552A1
• Filed: 08/11/2006
• Published: 02/14/2008
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: Latitude Broadband Incorporated
• Original Assignee: Latitude Broadband Incorporated
• Inventors: Dos Remedios, Rene Maria Buniel, Angeles, Joel Cruz Delos, Eliseeff, Ma Josefa Betia
• Granted Patent: US 7,599,290 B2
• Time in Patent Office: Days
• US Class Current: 370/395.21
• CPC Class Codes: H04L 41/0896 Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 43/0882 Utilisation of link capacity
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/115 using a dedicated packet
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/41 by acting on aggregated flows or links
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Methods and systems for providing necessary and sufficient quality-of-service (QoS), in a packet-based core transport network that utilizes dynamic setting of bandwidth management pipes or thresholds to obviate link congestion are disclosed. Congestion avoidance is a necessary and sufficient requirement in order to guarantee Quality of Service (QoS) in packet-based core networks.

A typical network is composed of a plurality of backbone links connecting edge nodes where backhaul links are aggregated. The backhaul links connect the backbone links to the remote sites serving the subscribers. In order to enforce bandwidth management policies, Access Controllers, which perform traffic shaping, are situated on each remote site.

In the event of a violation of certain link threshold settings, dynamic adjustment of the bandwidth management policies on affected Access Controllers is enforced. Various algorithms in determining the correlation between the link nearing congestion and the source or destination of traffic streams are also discussed. This invention implements a feedback control loop wherein probes at various points in the network checks for congestion states to guide bandwidth management threshold decisions in order to maintain the condition of non-congestion throughout the network. Capacity planning and congestion avoidance mechanisms work hand-in-hand to fulfill Service Level Agreements (SLA).

Claims

1. A system implementing feedback control mechanisms to manage available core transport bandwidth to guarantee QoS in packet-based networks, the system comprising of:

(a) Network Management System (NMS);

(b) Core QoS Manager;

(c) and Access Controllers.

5. A system in claim 1 wherein a Network Management System has a database of the network topology, dynamic link conditions and utilizations, and link congestion states which become the basis for link utilization, packet loss, or latency violation alerts, or combinations thereof.

6. A system in claim 1, wherein the Core QoS Manager is a software program module independent of or inside the NMS which perform resource management decisions to enforce QoS policies into the Access Controllers.

8. A system in claim 1, where the Core QoS Manager calculates the appropriate bandwidth management setting per Access Controller, the method consisting of:

(a) Defining utilization thresholds for each link;

(b) Checking for SLA CIR violations per link;

(c) Generation of network link upgrade alerts;

(d) Triggering dynamic bandwidth adjustment.

9. A Method in claim 8, wherein Access Controller pipe settings are determined by several algorithms such as:

(a) Distributing the backbone capacity equally or weighted among the affected Access Controllers;

(b) Distributing the backbone capacity among the affected Access Controllers in proportion to sum of subscriber CIRs in a backhaul;

(c) Configuring Access Controller pipe settings based on served subscriber CIR or MIR to proactively limit the traffic traversing a backhaul link;

(d) Identifying the Access Controller/s with the highest backhaul utilization to sum of sold backhaul CIRs ratio/s and performing a slow start process to set their pipes at a percentage of the initial setting;

(e) Setting the initial pipe to a predetermined value, and modifying this value based on the observed response;

(f) Combinations or variations of these algorithms.

2. A method to implement bandwidth management policy adjustments and a generalized way of implementing Resource and Admission Control Functions (RACF) in a Next-Generation Network (NGN), the method comprising of:

(a) Network Monitoring Feedback Control Mechanism;

(b) Resource Management;

(c) Policy Enforcement.

4. A method in claim 2, wherein each subscriber terminal, like a PC or IP phone, is given a committed information rate (CIR) and maximum information rate (MIR), as part of the Service Level of Agreement (SLA).

7. A method in claim 2, which includes algorithms for correlating link congestion state to the affected Access Controllers using the generated list of subscribers, IP addresses, or source/destination of traffic streams, or any identifier using:

(a) Passive Network Tree Traversal and/or routing table queries;

(b) Active Probing of Traffic passing through links.

3. An architecture wherein core transport of interest consists of:

(a) backbone links connecting edge nodes or aggregators of backhaul links;

(b) backhaul links connecting the backbone to the remote sites or base stations serving the subscribers, each served by an Access Controller