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Method and Apparatus for acquiring switch and ports information by exchanging Fibre Channel primitives

IP.com Disclosure Number: IPCOM000239352D
Publication Date: 2014-Nov-01
Document File: 5 page(s) / 61K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed are a method and apparatus for acquiring switch and ports information through Fibre Channel (FC) primitives. The methods include a device for querying an associated connected switch and switch port information by sending and receiving several FC primitives; special primitives are defined for this purpose.

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Method and Apparatus for acquiring switch and ports information by exchanging Fibre Channel primitives

Fibre Channel (FC) switches and directors are widely used in storage area networks (SANs). A single SAN environment

(SAN fabric) commonly contains multiple switches and/or directors. Thousands of hosts and devices can be connected to a single SAN fabric using switch/director ports.

Under the current situation, there are two ways to discover details of a fibre connection if one of its ends is already connected to a switch port. The first way is to physically trace the fibre cable from one end to another end by hand. This can require substantial physical effort if large numbers of FC cables exist. In addition, FC cables can be very long. The second way to determine switch and port information is to search relative port worldwide name (WWN) in each switch. The prerequisites of this method are:


1. The WWN of the device is known


2. The device is already logged in and known to the SAN fabric


3. User has the authority to log in and query switches

This method could be useless if one end of the fiber has no connection (this can be common in SAN fabric implementation or reconstruction) or if the device (e.g., FC Host Bus Adaptor (HBA)) is unable to log in to the SAN fabric.

All Fibre Channel communication is done in units of four 10-bit codes. This group of four codes is called a transmission

word. An ordered set is a transmission word that includes some combination of control (K) codes and data (D) codes.

In addition to the transfer of data, it is necessary for Fibre Channel communication to include some metadata. This allows for the setting up of links, sequence management, and other control functions. The metadata falls into two types:

primitives , which consist of a four-character transmission word and non-data frames , which are structures of greater

complexity. All primitives are four characters in length and all begin with the control character K28.5 in Fibre Channel protocol, followed by three data characters.

An easy mechanism is needed to provide switch port information to these hosts and devices for SAN fabric management. The same mechanism can also be beneficial to large-scale SAN fabric implementation and reconstruction in which thousands of fibre channel connections might be reconnected or need to be located.

The novel contribution is a set of methods for a device to query an associated connected switch and switch port

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information by sending and receiving several Fibre Channel primitives. Some special primitives are defined for this purpose.

In one embodiment, host or storage devices send these primitives and get response primitives from the FC switch after link initialization. These response primitives contain the switch and its port information. Hosts and storage devices can update the switch and port information each time, after it is connected to a switch port (i.e. link initialization or link reset).

In a...