DE102005046938A1 - Packet traffic class prioritization method for telecommunication network, involves providing error signal to nodes and transmitting classes of real time and fail-safe and best effort and fail-safe with high priority in error operation - Google Patents

Abstract

The method involves assigning packets to traffic classes of real time and fail-safe, real time and non fail-safe, best effort and fail-safe and best effort and non fail-safe. The classes are coded in an internet protocol (IP) header. The classes of real time and fail-safe and real time and non fail-safe are subjected to access control and are transmitted with high priority in error-free operation of a network. An error signal is provided to nodes of the network, and the classes of real time and fail safe and best effort and fail-safe are transmitted with high priority in case of error operation.

Description

Of the The subject of the application relates to a method for prioritizing Traffic classes of packets following the Internet Protocol formed with nodes and these connecting connecting portions Network forwarded.

• – Echtzeitfähigkeit, d. h. die Paketverzögerungs- und Verlustwahrscheinlichkeiten (und damit auch der Jitter) müssen gering sein
• – Ausfallsicherheit, d.h. der Verkehr muss auch im Falle eines Netzfehlers unbedingt durchkommen

Traffic can have two important quality of service requirements.

• Real-time capability, ie the packet delay and loss probabilities (and thus also the jitter) must be low
• - Resilience, ie the traffic must necessarily come through even in the case of a network error

So far became the real-time capability guaranteed by access control (AC). Resilient NAC can provide fail-safety for high-priority real-time traffic be realized by the access control AC only so much traffic allows, like can also be transported in the typical error case. In the area MPLS There Are Explicit Preemption Mechanisms Where Aggregate Tier Trunks can be canceled in case of overload To be able to exclude special aggregates from the forwarding. These solution has the disadvantage that the preemption will be explicitly triggered must and takes place only at the aggregate level. In addition, there are reservations against the use of MPLS technology.

the The subject of the application is the problem, the real-time capability and resilience in every combination per flow to be able to realize.

The Problem is solved by claim 1.

Of the according to the application mechanism is easy because no LSP's (virtual connections in MPLS, aggregates) must be terminated and the residual bandwidth of traffic that qualifies as non-fail-safe is, in case of error can still be used. The transition phases are not critical because they are relatively short, EA is always preferred and the quality of service from BA for may be demoted for a short time.

advantageous Further developments of the subject of the application are specified in the subclaims.

Of the The subject of the application will be described below as an exemplary embodiment in a to understanding required extent closer explained.

Of the The subject of the application comes in a data packet to the Internet Protocol forwarding network that connects to nodes / routers and these Connecting sections / links is formed, for use. The data packets like the net over the Access Controlling Access Facilities AC (for: Admission Control) are supplied. The above form a connection section / link forwarded data packets a river / fow.

to Control of access or flow like queues / priority Cues can be arranged, which are loaded depending on the traffic class.

• – EA, Echtzeitfähig und ausfallsicher
• – EN, Echtzeitfähig und nicht ausfallsicher
• – BA, Best Effort und ausfallsicher
• – BN, Best Effort und nicht ausfallsicher

The subject of the application is the decoupling of the properties of real-time capability and reliability. As a result, four traffic classes are formed.

• - EA, real-time capable and fail-safe
• - EN, real-time capable and not fail-safe
• - BA, Best Effort and failsafe
• - BN, Best Effort and not failsafe

These traffic classes can be encoded by the DSCP bits in the IP header. Access control AC is performed for the real-time capable traffic classes, but not for best effort traffic. As long as no error occurs only the real-time traffic is forwarded preferred. This can be done, for example, by forwarding the real-time traffic and best effort traffic with static priority scheduling, optionally such that EA is forwarded to EN before BA and BN, giving 3 priority queues. An error may occur in the network such that a node or a link section fails, resulting in a restriction of the data transport capacity of the network. In the event of an error, an error signal is propagated through the network informing the routers that a state of emergency has occurred and that the network capacity may now be insufficient. The prioritization / scheduling is then changed to prioritize real-time traffic with resiliency EA ahead of best effort traffic with resiliency BA, followed by traffic without resiliency in the order of real time traffic EN and best effort traffic BN. This can be realized, for example, by 4 static scheduling queues (EA, BA, EN and BN). The prioritization may alternatively be performed in the order (EA, BA, BN and EN) assuming that EN with insufficient prioritization is no longer functioning properly and therefore BN is to be preferred. The options are open, also the type of scheduling is selectable. As soon as the Exception state is canceled by a signal, the old scheduling is used again.

Claims (2)

Method for prioritizing traffic classes of packets, according to the Internet Protocol on using a node and this connecting connecting sections formed network passed become, consequently the packages the traffic classes - EA, real-time capable and fail-safe - EN, Real-time capable and not fail-safe - BA, Best Effort and Fail Safe - BN, Best Effort and not fail-safe be assigned, the traffic classes in the IP headers of packets are encoded the traffic classes EA and EN are subject to access control in error-free Operation of the network, the traffic classes EA and EN are forwarded with the highest priority, in the In case of error, an error signal is distributed to the nodes of the network and the traffic classes EA and BA forwarded with the highest priority become. A method according to claim 1 characterized the traffic classes are coded in the DSCP bits of the IP header become.