Nortel Networks NN43001-121 - Manual (Page 44)

44 Planning and engineering
Table 3
Load balancer minimum configuration
Service Protocol Port (range) Description
TLS pool TCP 5061 The client listens over the same connection that is
open to the server. By default, the server listens
on port 5061 (TCP). The server sends packets to
the client only over the client TLS session.
DCOM TCP 135 Installation and management.
— Optionally, configure the TCP pool on port 5060 for clients to connect
to the Load balancer through TCP.
Load Balancer requirements
A Load Balancer for the Office Communications Server (OCS) Enterprise
pool must meet the following requirements:
• The Load Balancer must expose a VIP Address through Address
Resolution Protocol (ARP).
• The VIP must have a single DNS entry, called the pool FQDN.
• The VIP must be a static IP address.
• The Load Balancer must allow multiple open ports on the same VIP.
Specifically, it must expose the ports 5060, 5061, 135, 80, 443, and 444.
• The Load Balancer must provide TCP-level affinity. This means that the
Load Balancer must ensure that it can establish TCP connections with
one Office Communications Server in the pool and all traffic on that
connection is destined for that same Office Communications Server.
• The Load Balancer must provide a configurable TCP idle-timeout
interval with a maximum value greater than or equal to the minimum of
the REGISTER refresh or SIP Keep-Alive interval.
• The Load Balancer must support a rich set of metrics (round robin,
least connections, and weighted). Nortel recommends a weighted least
connections-based load balancing mechanism for the Load Balancer.
This means that the load balancer ranks all Office Communications
Servers based on the weight assigned to them and the number of
outstanding connections. The Load Balancer use the rank to pick the
Office Communications Server to use for the next connection request.
• The Load Balancer must detect Office Communications Server
availability by establishing TCP connections to ports 5060, 5061, or
both (often called a heartbeat or monitor). The polling interval must
be a configurable value with a minimum value of at least five seconds.
The load balancer must not select an Office Communications Server
that shuts down until it can establish a successful TCP connection
(heartbeat) again.
Nortel Communication Server 1000
Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007
NN43001-121 01.03 Standard
Release 5.0 30 April 2008
Copyright © 2005–2008, Nortel Networks
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