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Extreme Networks' Ethernet Automatic Protection Switching (EAPS) Version 1 (RFC3619)

IP.com Disclosure Number: IPCOM000020064D
Original Publication Date: 2003-Oct-01
Included in the Prior Art Database: 2003-Oct-23
Document File: 8 page(s) / 14K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Shah: AUTHOR [+2]

Abstract

This document describes the Ethernet Automatic Protection Switching (EAPS) (tm) technology invented by Extreme Networks to increase the availability and robustness of Ethernet rings. An Ethernet ring built using EAPS can have resilience comparable to that provided by SONET rings, at a lower cost and with fewer constraints (e.g., ring size).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 24% of the total text.

Network Working Group S. Shah

Request for Comments: 3619 M. Yip

Category: Informational Extreme Networks

October 2003

Extreme Networks'

Ethernet Automatic Protection Switching (EAPS)

Version 1

Status of this Memo

This memo provides information for the Internet community. It does

not specify an Internet standard of any kind. Distribution of this

memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

This document describes the Ethernet Automatic Protection Switching

(EAPS) (tm) technology invented by Extreme Networks to increase the

availability and robustness of Ethernet rings. An Ethernet ring

built using EAPS can have resilience comparable to that provided by

SONET rings, at a lower cost and with fewer constraints (e.g., ring

size).

1. Introduction

Many Metropolitan Area Networks (MANs) and some Local Area Networks

(LANs) have a ring topology, as the fibre runs. The Ethernet

Automatic Protection Switching (EAPS) technology described here works

well in ring topologies for MANs or LANs.

Most MAN operators want to minimise the recovery time in the event

that a fibre cut occurs. The Ethernet Automatic Protection Switching

(EAPS) technology described here converges in less than one second,

often in less than 50 milliseconds. EAPS technology does not limit

the number of nodes in the ring, and the convergence time is

independent of the number of nodes in the ring.

Shah & Yip Informational [Page 1]

RFC 3619 Extreme Networks' EAPS October 2003

2. Concept of Operation

An EAPS Domain exists on a single Ethernet ring. Any Ethernet

Virtual Local Area Network (VLAN) that is to be protected is

configured on all ports in the ring for the given EAPS Domain. Each

EAPS Domain has a single designated "master node". All other nodes

on that ring are referred to as "transit nodes".

Of course, each node on the ring will have 2 ports connected to the

ring. One port of the master node is designated as the "primary

port" to the ring, while the other port is designated as the

"secondary port".

In normal operation, the master node blocks the secondary port for

all non-control Ethernet frames belonging to the given EAPS Domain,

thereby avoiding a loop in the ring. Existing Ethernet switching and

learning mechanisms operate per existing standards on this ring.

This is possible because the master node makes the ring appear as

though there is no loop from the perspective of the Ethernet standard

algorithms used for switching and learning. If the master node

detects a ring fault, it unblocks its secondary port and allows

Ethernet data frames to pass through that port. There is a special

"Control VLAN" that can always pass through all ports in the EAPS

Domain, including the secondary port of the master node.

EAPS uses both a polling mechanism and an alert mechanism, described

below, to verify the connectivity of the ring and quickly detect any

faults.

2.1. Link Down Alert

When a transit node detects a link-down on any of...