Redundancy With Load Balancers - Nortel 1000 Fundamentals

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For more information about Load Balancer requirements, see Microsoft
Office Communications Server 2007 Document: Planning Guide.
Download Microsoft technical documentation from the Download Center at
www.microsoft.com.

Redundancy with Load Balancers

You can add redundancy to your network by placing Load Balancers, such
as a Nortel Application Switch, between the OCS 2007 Front End servers
and Mediation Servers, and between the Mediation Servers and the OCS
2007 Proxy Servers.
The outgoing Load Balancer balances SIP invites from the Mediation Server
to the OCS Proxy server. The Mediation Server sends all SIP Invites to
the Virtual IP (VIP) of the outgoing Load Balancer. The Load Balancer
then sends the SIP Invite to the least busy Office Communications Server
2007 OCS Proxy.
The incoming Load Balancer balances SIP invites from the Mediation Server
to the least busy Front End server. This is the same load balancer that is
used when the Office Communicator addresses the pool for registration.
The OCS Proxy sends all SIP invites to the Virtual IP (VIP) of the incoming
Load Balancer.
Redundancy is also ensured for calls to an Office Communicator user by
having each OCS Proxy server register to the MCM and the Mediation
Server to the NRS with a unique registration ID and different cost factor.
Therefore, if one of the OCS Proxy servers is unavailable, the next one
is selected.
High-scale and high availability configuration
The pool of Front End servers processes inbound and outbound traffic. In
this example, the Load Balancer routes incoming SIP messages to the
less busy server based on a configured algorithm. The Load Balancer VIP
Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007
Copyright © 2005–2008, Nortel Networks
.
Every Office Communications Server must have exactly one network
adapter. Multihoming an Office Communications Server is not
supported. If a 10/100 network adapter does not meet the required
bandwidth constraints, a gigabit network adapter must be used.
The network adapter must have at least one static IP address. This IP
address will be used for the incoming load-balanced traffic.
The computer must have a registered FQDN. The IP address registered
for this FQDN must be publicly accessible from within the enterprise.
The Load Balancer must include less than one gigabit capacity for up to
50 000 concurrent client connections. One gigabit of capacity is required
to support more than 50 000 concurrent client connections.
Nortel Communication Server 1000
NN43001-121 01.03 Standard
Release 5.0 30 April 2008
Load Balancer planning 45