RU2803648C2 - System and method for traffic routing in mpls network - Google Patents

Abstract

FIELD: communication network traffic routing.

SUBSTANCE: system includes a routing element configured to share one or more schemas among multiple instances of an Intermediate System-to-Intermediate System (IS-IS) routing protocol, where each of the multiple routing protocol instances is associated with its own unique database, and wherein at least one routing element comprises a control object configured to: control a plurality of traffic control software agents, each of the traffic control software agents being associated with a corresponding database from among said unique databases, and allocate available resources to corresponding routing protocol instances for transmission of traffic through them; updates of the mentioned databases; and for traffic to be transmitted through a particular instance, determining on an ad hoc basis one or more databases from a plurality of said databases, wherein said selected one or more databases will be used in determining the path through which said traffic will be transmitted.

EFFECT: control of traffic flows in MPLS network

5 cl, 2 dwg

Description

Field of technology to which the invention relates

The present disclosure relates generally to the field of networking and, in particular, to the routing of network communication traffic flows.

List of abbreviations

BGP – Border Gateway Protocol

CPU - central processing unit

CSPF – Constrained Shortest Path First

ERO – Explicit Route Object

FIB – forwarding database

FPGA – Field Programmable Gate Array

IETF - Internet Engineering Task Forces

IGP – Internal Gateway Protocol

IS-IS – intermediate system to intermediate system routing protocol

LSDB – link state database

MI-RTR – router with multi-network support

MPLS – Multiprotocol Label Switching

MPLS-NH - Multiprotocol Label Switching - Next Hop

PDU – protocol data unit

RFC - Request for Comments

RIB – routing information base

RSVP – Resource Reservation Protocol

RTR – router

SI-RTR – router with single network support

SRLG – group of communication lines with a common risk

TE – traffic management

TED – Traffic Management Database

TLV – type-length-value communication format

State of the art

The ISO 10589 protocol is an international standard that was developed to establish connectivity and availability between end systems and intermediate systems on an individual subnet. However, this protocol allows only one object to operate in a given scheme.

IETF RFC 8202 "IS-IS Multi-Instance" then defined a mechanism that allows a single router to share one or more schemes among multiple instances of the Intermediate System-to-Intermediate System (IS-IS) routing protocol.

The use of multiple instances allows the resources associated with each instance to be isolated, where routers produce an instance-specific environment, while each instance can be configured to support multiple topologies. Each topology is associated with a unique link state database (LSDB), and each protocol data unit (PDU) contains a type-length-value (TLV) link format identifying the instance and topology (or topologies) to which that PDU belongs. .

RFC 8202 discloses the option to configure interfaces in a multi-instance environment and can also be used to handle the IPv4, IPv6 aspect of traditional embedded routing topology. However, no solutions exist to handle the traffic control requirements of an MPLS network that relies on the Intermediate System to Intermediate System (IS-IS) routing protocol as the Interior Gateway Protocol (IGP), known as the IS-IS instance. TE, which is used to exchange routing information between gateways (usually routers) within an autonomous system (such as an enterprise LAN system).

MI-RTR (IS-IS Multi-Instance Router) is referred to as "Multi-Instance Router". When such a router is part of an MPLS traffic management (TE) network, traffic management database (TED) support is required for each IS-IS instance in order to satisfy the CSPF needs of the MPLS-TE protocol.

Each TED must contain unique topology information related to the corresponding IS-IS instance, including the routers and interfaces associated with the instance, with all relevant TE information such as bandwidth availability, administrator groups, and SRLGs.

An MPLS transport protocol such as RSVP-TE uses a combination of Constrained Shortest Path First (CSPF) and Explicit Route Objects (EROs) to determine how traffic will be routed through the network.

The present disclosure aims to provide a solution that overcomes the above-described disadvantages associated with traffic flow control.

The essence of the invention

The disclosure may be summarized by reference to the accompanying claims.

The objective of the present disclosure is to implement a new network element and software operating in a communications network that allows monitoring of known traffic flows.

Other objects of the present disclosure will become apparent from the following description.

According to a first embodiment of the present disclosure, a system is provided for use in an MPLS network, the system comprising at least one routing element configured to share one or more schemes among multiple instances of an intermediate system to intermediate system (IS) routing protocol. -IS), wherein each of the multiple instances is associated with a unique database, and wherein the at least one routing element comprises a processor configured to perform the functions of a control entity comprising:

managing a plurality of traffic management software agents, each associated with a corresponding database, and allocating available resources to the respective instances;

updating at least one of the plurality of databases; And

for traffic to be transmitted through a particular instance, determining the neighboring instance through which that traffic will be transmitted, based on information contained in a database associated with the particular instance through which the traffic will be transmitted.

According to another aspect of the present invention, there is provided a method for use in an MPLS network by a control entity that is contained in a routing element, where the routing element is configured to share one or more schemes among multiple instances of an Intermediate System to Intermediate System (IS) routing protocol. IS), and wherein each of the multiple instances is associated with a unique database, the method comprising the steps of:

managing a plurality of traffic management software agents, each of which is associated with a corresponding database, and allocating available resources to the respective instances;

updating at least one of the plurality of databases; And

for traffic to be transmitted through a particular instance, determining the neighboring instance through which that traffic will be transmitted, based on information contained in a database associated with the particular instance through which the traffic will be transmitted.

According to another embodiment, the step of updating at least one of the plurality of databases comprises updating each of the plurality of databases.

Brief description of drawings

The accompanying drawings, which are included herein and form a part of this specification, illustrate several embodiments of the disclosure and, together with the description, serve to explain the principles of the embodiments disclosed herein.

In fig. 1 is a schematic view of multiple instances of a TE network topology provided in accordance with an embodiment of the present invention; And

In fig. 2 is a schematic view of a MI-PTP forwarding and routing table structure provided in accordance with another embodiment of the present invention.

Detailed Description of the Invention

Some of the specific details and meanings in the following detailed description relate to certain examples of the disclosure. However, this description is provided by way of example only and is in no way intended to limit the scope of the invention. As will be appreciated by those skilled in the art, the claimed method and apparatus may be implemented using other methods that are themselves known in the art. In addition, the described embodiments contain various steps, not all of which are required in all embodiments of the invention. The scope of the invention can be summarized as follows:

Let us consider the following example, illustrated in FIG. 1, wherein the communication system is constructed in accordance with an embodiment of the present disclosure and operates over an MPLS network. The communication system that is depicted in this drawing includes a plurality of routers associated with multiple instances (that is, multiple instance capable routers) MI-RTR1 to MI-RTR4, and a plurality of single instance routers (SI-RTRs), each of which associated with a single instance.

Prior art solutions previously adopted in the industry have relied on selecting one instance from a plurality of available instances to act as a fixed instance through which traffic will be transmitted, using a single database associated with that instance.

The present invention provides another solution based on a completely different basic principle. According to an embodiment of the present invention, each of the plurality of instances is associated with its own database, and the selection is made based on a specific determination of which of the plurality of databases will be used in determining the path along which traffic will be transmitted. Another challenge related to this solution that needs to be addressed is how to manage these multiple databases and allocate resources between them. To achieve this, each database associated with one of the many instances is equipped with a traffic management software agent. The management entity included in the router is configured to update each of the databases, for example, updates associated with changes that have occurred to their adjacent neighbors, and determine which of the neighbors will be used to forward traffic.

Multiprotocol Label Switching (MPLS) traffic management software enables the MPLS backbone to replicate and extend the traffic management capabilities of Layer 2 networks. Traffic management is essential for service provider and ISP backbone networks that support high throughput ability in networks that are very resilient. MPLS Traffic Management provides a comprehensive approach to traffic management. With MPLS, traffic management capabilities are integrated into Layer 3, which optimizes the routing of IP traffic within the constraints of bandwidth and backbone network topology.

IS-IS layer capabilities of routers can be configured on a global and/or per-interface basis. Interface level parameters can define the interface's routing level, as well as neighbor capabilities and parameters that define the environment that is installed. Typically, when an IS-IS instance is enabled, the router can operate as either a layer 1 router or a layer 2 router with associated databases. Routers perform separate "constrained shortest path first" (SPF) calculations for Layer 1 area routing and Layer 2 multi-area routing to create the IS-IS routing table for the IS-IS instance.

As can be seen from Fig. 1, both MI-RTR3 and MI-RTR4 are associated (eg, participating in a broadcast scheme) each individually with instances B and C. There are multiple RSVP-TE tunnels that run between MI-RTR3 and MI-RTR4, where each of these tunnels is associated with a different IS-IS instance.

Resource Reservation Protocol - Traffic Engineering ("RSVP-TE") is an extension of the Resource Reservation Protocol (RSVP) for traffic engineering. It supports resource reservation in an IP network. Applications running on IP end systems can use RSVP to indicate to other endpoints the nature of the packet streams they want to receive (eg, throughput, packet corruption, maximum packet, etc.).

The RSVP-TE protocol, described in RFC 3209 and RFC 5151, generally allows the establishment of MPLS label switched routes (LSPs) while taking into account network constraint parameters such as available bandwidth and explicit hops.

In this example, RSVP-TE is used to establish a tunnel between two endpoints (MI-RTR) in a communications network based on Constrained Shortest Path First (CSPF) information obtained from one IS-IS TE instance.

At runtime, a communications network operator may establish a tunnel that is explicitly associated with a given IS-IS instance selected from a plurality of instances supported by the corresponding MI-RTR.

When establishing a tunnel, the corresponding MI-RTR can use the same set of virtual loopback interfaces, which are used as the source of RSVP signaling, which serve as destinations for all local IS-IS instances configured on the corresponding devices.

MI-RTR can be configured with multiple instances to support installation of corresponding IS-IS routes into a single routing information base (RIB) table. To distinguish between different IS-IS paths reaching the same destination, each IS-IS instance is preferably given a user-configurable administrative distance preference.

Using the RIB table, the associated processor performs route selection based on the administrative distance value (a lower value means higher priority), and the selected route is then entered into the forwarding database (FIB) table.

If an MI-RTR is associated with multiple RSVP-TE tunnels aimed at a destination router, where each of the RSVP-TE tunnels is associated with a different IS-IS instance, the RIB table is preferably used by the processor to select one of the RSVP-TE tunnels by implementing an administrative distance algorithm .

In case MI-RTR, acting as the head router (i.e., the entry point into the RSVP-TE tunnel), is used to establish RSVP-TE tunnels in the designated MPLS table, MI-RTR is used to resolve recursive next-hop protocol routes such as BGP, which in turn may require MPLS reachability to the destination (that is, a family of unicast addresses labeled BGP).

Moreover, when two adjacent MI-RTRs belong to one or more multiple IS-IS-TE instances, special processing is required to allocate bandwidth on the shared resource interface. The RSVP tunnel may require some bandwidth allocation on the interface for a given IS-IS-TE instance. However, the bandwidth allocation may have to be changed for the same interface when another instance associated with this router is used. MI-RTR can be configured with multiple logical interfaces (subinterfaces), each dedicated to a different IS-IS-TE instance, and using shared resource calculation in RSVP to be able to influence changes when switching from one instance to another .

The issue of prioritizing RSVP-TE tunnels for multiple instances can be resolved by employing a first-come-first-out mechanism, where the RSVP priority mechanism (soft or hard) is used to establish RSVP-TE tunnels based on the available TED IS-IS information.

In fig. 2 shows an exemplary schematic view of a MI-RTR routing and forwarding table created in accordance with another embodiment of the present invention. As can be seen in this example, the table contains details of the MI-RTR system, where IS-IS is associated with multiple traffic management databases and the RSVP is updated with information in the IS-IS TED for each instance. IS-IS information is preferably included in the IPv4/IPv6 routing table, and RSVP-TE (tunnel permission) information is contained in the MPLS-NH table.

Other embodiments of the present invention will become apparent to those skilled in the art upon consideration of the description and practice of the invention disclosed herein. It is intended that the description and examples should be considered only as illustrative of the true scope and spirit of the invention as set forth in the following claims.

Claims (11)

1. A system for routing traffic in a multiprotocol label switching (MPLS) network, the system characterized in that it contains a routing element configured to share one or more schemes among multiple instances of the Intermediate System-to-Intermediate System (IS-IS) routing protocol ), wherein each of the multiple routing protocol instances is associated with its own unique database, and wherein said at least one routing element comprises a control entity configured to: managing a plurality of traffic management software agents, each of the traffic management software agents being associated with a corresponding database among said unique databases, and allocating available resources to corresponding routing protocol instances for transmitting traffic therethrough; updating databases associated with corresponding routing protocol instances; And for traffic to be transmitted through a particular instance, determining on an ad hoc basis one or more databases from a plurality of databases associated with said multiple routing protocol instances, wherein said selected one or more databases will be used in determining the path through which the mentioned traffic will be transmitted. 2. The system according to claim 1, in which, for traffic that must be transmitted through a specific routing protocol instance, said control entity determines the neighboring routing protocol instance through which said traffic will be transmitted, based on information contained in a database associated with a specific instance of the routing protocol through which said traffic will be transmitted. 3. A method for routing traffic in a multiprotocol label switching (MPLS) network by a control entity containing a routing element, wherein said method is characterized in that the routing element is configured to share one or more schemes among multiple instances of an intermediate system-intermediate system routing protocol "(IS-IS), wherein each of the multiple routing protocol instances is associated with its own unique database, the method comprising the steps of: managing a plurality of traffic management software agents, each of the traffic management software agents being associated with a corresponding database among said unique databases, and allocating available resources to corresponding routing protocol instances for transmitting traffic therethrough; updating databases associated with corresponding routing protocol instances; And for traffic to be transmitted through a particular routing protocol instance, determining on an ad hoc basis one or more databases from a plurality of databases associated with said multiple routing protocol instances, wherein said selected one or more databases will be used in determining the path, through which the mentioned traffic will be transmitted. 4. The method of claim 3, wherein for traffic to be transmitted through a particular routing protocol instance, a neighboring routing protocol instance through which said traffic will be transmitted is determined based on information contained in a database associated with the specific protocol instance routing through which the mentioned traffic will be transmitted. 5. The method of claim 3, wherein the step of updating databases associated with respective routing protocol instances includes updating each of the plurality of databases.