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END-TO-END AND SERVICE FUNCTION FORWARDER (SFF)-TO-SFF SERVICE FUNCTION PATH CONTINUITY CHECK USING BIDIRECTIONAL FORWARDING DETECTION (BFD)

IP.com Disclosure Number: IPCOM000247381D
Publication Date: 2016-Aug-30
Document File: 6 page(s) / 207K

Publishing Venue

The IP.com Prior Art Database

Related People

Nagendra Kumar Nainar: AUTHOR [+3]

Abstract

A solution is presented herein that uses an extended Service Function Chain trace to query a Bidirectional Forwarding Detection (BFD) Discriminator from each Service Function Forwarding (SFF) in any specific Service Function Path (SFP). Each Service Function will simply increment the Service Index (SI) and forward back to the SFF if the received packet has the O bit set and NextProto is set to BFD. In such cases, the Service Function will skip packet processing. Each SFF will look to use the details in a Network Service Header (NSH) header to determine if the packet should be handled locally by the BFD module. If not, it simply forwards the packet as per SFF table.

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Page 01 of 6

END-TO-END AND SERVICE FUNCTION FORWARDER (SFF)-TO-SFF SERVICE

FUNCTION PATH CONTINUITY CHECK USING BIDIRECTIONAL

FORWARDING DETECTION (BFD)

AUTHORS:

Nagendra Kumar Nainar Carlos M. Pignataro

Jim Guichard

CISCO SYSTEMS, INC.

ABSTRACT

    A solution is presented herein that uses an extended Service Function Chain trace to query a Bidirectional Forwarding Detection (BFD) Discriminator from each Service Function Forwarding (SFF) in any specific Service Function Path (SFP). Each Service Function will simply increment the Service Index (SI) and forward back to the SFF if the received packet has the O bit set and NextProto is set to BFD. In such cases, the Service Function will skip packet processing. Each SFF will look to use the details in a Network Service Header (NSH) header to determine if the packet should be handled locally by the BFD module. If not, it simply forwards the packet as per SFF table.

DETAILED DESCRIPTION

     Service Function Chaining (SFC) is one of the hot technologies in the industry that is considered to be a basic requirement to realize network function virtualization (NFV) implementations. Operators are interested in checking the liveliness of a Service Function Path (SFP) and take necessary actions in case of failure detection.

    Unlike traditional multi-hop Bidirectional Forwarding Detection (BFD), an end- to-end BFD for SFP check requires some considerations to avoid the Service Function (SF) applying the policy on BFD packets and dropping them, resulting in false alarms.

    Presented herein is a solution that extends BFD to adhere to SFC environments and provides the machinery to apply the same to check the liveliness of an SFP using various options including:


End-to-End BFD session

Copyright 2016 Cisco Systems, Inc.

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SFF-to-SFF BFD session

The Originator (classifier node) will trigger an "SFC trace" as defined in draft-

penno-sfc-trace with a flag (BFD Discriminator query) from each SFF along a specific SFP. The Originator will generate a BFD control packet and set "Your Discriminator" (YD) from value received from SFC reply.

    When the Originator (classifier, normally) is performing an End-to-End SFP Continuity Check, it will set YD as the Discriminator from the last SFF.

    When the Originator (Classifier or SFF) intends to perform a Continuity Check to the next SFF, it will set YD as Discriminator of the next SFF.

    The BFD control packet will be encapsulated with a Network Service Header (NSH) header with respective SFP identifier (ID) (to be validated). A BFD marker is set in the NSH header (O bit in NSH header set with NextProto=BFD). The NSH further includes a metadata type (MD-Type)=0x1 carrying relevant details.

    Each Service Function will simply increment the Service Index (SI) and forward back to the SFF if the received packet has the O bit set and NextProto is BFD. In such cases, the SF will skip packet processing.

    Each Service Function Forwarder will look to use the details in the NSH header...