WO2001054357A1

WO2001054357A1 - Method for optimally making resources available in a communications network that functions according to an internet protocol

Info

Publication number: WO2001054357A1
Application number: PCT/DE2001/000072
Authority: WO
Inventors: Martin Winter; Peter Schneider; Rudolf Stelzl
Original assignee: Siemens Aktiengesellschaft
Priority date: 2000-01-24
Filing date: 2001-01-10
Publication date: 2001-07-26
Also published as: AU2001240416A1

Abstract

In internet communications networks (ISP1, ISP2), the state of the art utilizes a modified DiffServ mechanism for guaranteeing the quality of service. For this, it should be ensured that the overall amount of prioritized traffic is limited via central bandwidth brokers. The central function, however, proves to be problematic with regard to the expandability of the communications network. The invention resolves this problem by extensively separating functions that have been centrally conducted up to now such as the Admission Control Function (ER) and the Resource Management Function (RCA).

Description

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This checks against statically set maximum values and rejects bandwidth requests if necessary. If the bandwidth broker knows the network topology and the routing decision of the core router, which is located between the input and output edge router, the availability of the desired bandwidth can be checked along the entire path. The two network functions "Admission Control" and "Resource Management" are thus integrated in the Bandwidth Broker. The bandwidth broker thus has a central function in the network.

With this proposed solution, a certain dynamic can be introduced in the management of network resources. Due to its central function, the bandwidth broker has to process all reservations of a DiffServ domain. However, this gives rise to the problem that the expansion of the communication network (scaling) is becoming more and more complex since the addition of further subscribers in the central area, the bandwidth broker, entails an administration which can hardly be handled.

The invention has for its object to show a way how the expansion of a communication network can be carried out easily and flexibly with simple means.

An advantage of the invention is in particular that decoupling of admission control and resource management is essentially carried out. This is done by integrating the admission control into the peripheral edge routers of the communication network, and resource management remains in the bandwidth broker. This means that admission control is decentralized. The bandwidth broker is thus relieved and only carries out resource management tasks.

This has the advantage that the communication network can be expanded at any time without further effort by additional participants (scalability). For this only the in To expand the upcoming edge router, the "bottleneck" of the central device of the bandwidth broker with regard to the admission control function is eliminated.

Another advantage is that the dynamic resource control supports a restriction of the prioritized traffic and an optimization of network parameters, which improves the service guarantees and the utilization of the network. By restricting the prioritized traffic, the probability of packet loss in the

Core network reduced. The packet loss probability can be controlled via the maximum values of the bandwidths per DiffServ class.

In addition, the Egde router is able to satisfy bandwidth peaks during the reservation due to bandwidth requirements with its bandwidth broker if not all edge routers request additional bandwidth at the same time.

Another particular advantage is that this architecture can be viewed as fault-tolerant. The failure of a bandwidth broker only leads to a temporarily suboptimal utilization of the network, but not to further failures.

Advantageous developments of the invention are specified in the subclaims.

The invention is explained in more detail below with reference to an exemplary embodiment shown in the figures.

The network architecture according to the invention is shown in the figure. Accordingly, subscriber H (host) is introduced to Internet service provider ISPL, ISP2. For their part, these have a plurality of nodes which are networked with one another. Core router CR and edge router ER are arranged in the nodes. The Edge Router ER are an interface to consider the participants H and between Internet service providers. In the former case, the edge routers ER can function as a dial-up computer. The core routers CR are used to switch the information originating from the subscribers H through the network. Furthermore, each Internet service provider ISP1, ISP2 is assigned a higher-level control device RCA (Resource Control Agent), which works as a bandwidth broker and in which the function of resource management is integrated.

The task of the edge router ER is on the one hand to process the signaling information originating from the subscribers H. On the other hand, an admission control of a connection request is carried out independently on the basis of a bandwidth allocated by the resource control agent RCA. This is a maximum value for prioritized traffic, which ensures that any requests arriving from a subscriber H do not have to be rejected due to a lack of bandwidth.

The Resource Control Agent RCA automatically allocates the available resources to the Edge Router ER. It is always the top priority to ensure that every Edge Router ER has as much free capacity in the different DiffServs

Allocate traffic classes so that this can with high probability allow any further request arriving from a subscriber H.

Depending on the knowledge of the network topology and the network load, the Resource Control Agent RCA can choose different algorithms for the distribution of resources:

One of the options is to use the resource control agent RCA to load the traffic classes on the edge

To have routers ER checked. The latter can also have explicit requirements for the Resource Control Agent RCA put. Based on this information, the resource control agent RCA may redistribute the allocated maximum values into the edge router ER. This means that existing idle capacity in one of the edge routers ER is made available to an edge router ER that urgently needs this capacity.

In addition, information about the utilization of the core router CR can be stored in the resource control agent RCA. With this information, the resource control agent RCA can then distribute the bandwidth capacity to the edge routers ER in such a way that the total load in the network is optimized.

In addition, the resource control agent RCA can also control the allocation of the bandwidth to the traffic classes in the core routers CR and, if necessary, adapt it to the current load situation. If requirements are already known in advance, the Resource Control Agent RCA can allocate the resources some time before the actual requirements.

The basic advantage of the invention can be seen in the fact that this procedure decouples the functions "Admission Control" and "Resource Management". This is the only way to make access control possible, in which the Edge Router ER can make the approval decision locally. The Resource Control Agent RCA takes on the sole task of resource management and ensures that every Edge Router ER can answer incoming requests with the highest possible probability.

This procedure can also be used to transfer traffic between several Internet service providers. Provides, for example, the Resource Control Agent RCA of the Internet Service

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In a further expansion stage it is provided that the resource control agent RCA additionally monitors the load in the core routers CR. It uses this information to adjust the bandwidth pool for the edge devices accordingly.

Ultimately, the Resource Control Agent can use RCA learning algorithms to find out how the load on the edge routers influences the load on the core net. Such algorithms allow better utilization of the core net. The Resource Control Agent RCA can use the load information from the Core Net to change parameters for the routing protocols. This allows a high load on a link to be redirected to other, less loaded links.

Claims

claims

1. Network architecture for providing resources in a communication network, which are made up of at least one higher-level control device (RCA), a plurality of edge routers (ER), to which the subscribers (H) are led, and a further plurality of core routers (CR) , and which has an admission control function that accepts requests from subscribers (H) based on the allocation of bandwidth from a resource management function, characterized in that the admission control function essentially in the majority of edge routers (ER) and the resource management function is integrated in the higher-level control device (RCA), the resource management function of the admission control function always allocating so much free bandwidth before the occurrence of a connection request that any further connection request can be permitted with high probability.

2. Network architecture according to claim 1, characterized in that the information through the communication network according to a

Internet protocol (TCP / IP, UDP / IP).

3. Network architecture according to claim 1, 2, characterized in that the higher-level control device (RCA) controls the utilization of the traffic classes on the plurality of edge routers (ER).

4. Network architecture according to claim 1, 2, characterized in that the majority of the edge routers (ER) make explicit demands on the higher-level control device (RCA), whereupon these optionally redistribute the allocated bandwidth in the majority of the E ge routers (ER) performs.

5. Network architecture according to one of the preceding claims, characterized in that the higher-level control device (RCA) additionally determines the load in the further plurality of core routers (CR), in accordance with the result provided by the edge router (ER) Allocated bandwidth if necessary.

6. Network architecture according to one of the preceding claims, characterized in that the higher-level control device (RCA) additionally controls the distribution of the bandwidth to the traffic classes in the further plurality of core routers (CR) and, if necessary, adapts to the current load situation.