FW: Extended RAC and multicast

From: Iggy Fernandez <iggy_fernandez_at_hotmail.com>
Date: Mon, 14 Apr 2014 11:29:37 -0700
Message-ID: <BLU179-W758ED732E9A1041B02D3D4EB510_at_phx.gbl>

A friend asked me a question that I could not answer. He is in the planning stages of an "extended RAC deployment" and is looking for confirmation that multicasting is optional. Help would be appreciated.
Kindest regards,
-- Iggy FernandezEmail: iggy_fernandez_at_hotmail.comCellphone: (925) 478 3161Blog: So Many Manuals So Little Time Author of Beginning Oracle Database 11g AdministrationEditor of the NoCOUG JournalLecturer at University of Washington Professional and Continuing Education

Date: Mon, 14 Apr 2014 11:13:03 -0700
From: kulkarniravi_at_yahoo.com
Subject: Extended RAC and multicast
To: iggy_fernandez_at_hotmail.com

I am looking to setup extended RAC for my client. The details are as following:

The two data centers are separated by a distance of less than 20 miles.

They are connected by a high speed dedicated connection.

Operating System: RHEL 6 64 bit

Database version: 11gR2 (

Hardware: Four servers with 4x16 configuration

All the documentation I have reviewed so far says multicast should be enabled on the private interconnect between all the nodes of a RAC database. However, my network resources tell me that multicasting is not enabled across the data centers and VLANs do not span across the data centers. The only reference I have seen to multicasting requirement is in this Oracle document:

http://docs.oracle.com/cd/E16655_01/install.121/e17888/networks.htm#CWLIN476 Specifically it makes the following assertion:

"You do not need to enable multicast communications across routers"

Does this mean, multicast is optional?


Ravi Kulkarni                                                

Received on Mon Apr 14 2014 - 20:29:37 CEST

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