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Performance Improvement in Policy Based Routing Without Route Cache

IP.com Disclosure Number: IPCOM000245246D
Publication Date: 2016-Feb-22
Document File: 5 page(s) / 251K

Publishing Venue

The IP.com Prior Art Database

Abstract

In Policy Based Routing (PBR) implementations without route cache, performance depends on preferential treatment for forwarding or termination traffic, which negatively impacts the performance of traffic with lower preference. The lower preferential traffic has to lookup at least two PBR rules and two routing tables to send the packet to the destination. This paper describes a method with which a single PBR & Route lookup is performed for termination packet or forwarding packet. PBR rules can be stored using Algorithmic Access Control List (AACL) accelerator to accelerate PBR lookup. This method improves the performance for termination/forwarding traffic significantly depending on the preferential treatment.

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Performance Improvement in Policy Based Routing Without Route Cache

Abstract

In Policy Based Routing (PBR) implementations without route cache, performance depends on preferential treatment for forwarding or termination traffic, which negatively impacts the performance of traffic with lower preference.  The lower preferential traffic has to lookup at least two PBR rules and two routing tables to send the packet to the destination.  This paper describes a method with which a single PBR & Route lookup is performed for termination packet or forwarding packet.  PBR rules can be stored using Algorithmic Access Control List (AACL) accelerator to accelerate PBR lookup.  This method improves the performance for termination/forwarding traffic significantly depending on the preferential treatment.

Introduction

PBR provides a method to select a specific next-hop for a packet.  PBR consists of a set of ordered rules, with each rule pointing to a routing table.  Traditionally, routing of a forwarding packet happens by looking up in the local routing table and then forwarding the routing table.  A local routing table stores all the routes related to the termination traffic (traffic destined to the device).  Forwarding the routing table stores the routes for forwarding traffic.  Algorithmic Access Control List (AACL) accelerator provides support for accelerating ordered list lookups. As PBR is an ordered list, the AACL accelerator can be used to store PBR rules and accelerate PBR based routing lookup.

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Design and Implementation

With no route cache based implementations, preferential treatment for forwarding or termination traffic negatively impacts the route lookup performance with lower preference.  Considering a scenario where preferential treatment is given for the termination traffic, the following will be the number of lookups for the termination & forwarding traffic

CASE I: Termination traffic i.e. packets destined to the router

For packets destined for the router, one PBR rule lookup and one route lookup occurs.

 
 

Figure 1. PBR lookup for the termination traffic

 
 

Case II: Forwarding traffic i.e. packets to be forwarded by the router

In forwarding path, two PBR lookups and two route table lookups occur, which results in perf...