Specifications

DESIGN GUIDE - Data Center LAN Connectivity Design Guide

Server Virtualization

Server virtualization capabilities such as those delivered by Microsoft Virtual Server or VMware Infrastructure are

increasingly being deployed to increase the operational efficiency of server infrastructure and in turn lower power,

cooling and space requirements. While delivering operational efficiency, the virtualized infrastructure places new

demands on the access layer of the data center. A high-performance network infrastructure is critical in delivering

the required levels of scalability, availability, performance and security required for virtualized operating systems and

applications.

Understanding the density of the planned virtual server infrastructure is critical in defining key IP addressing.

Typically most networks are designed to accommodate approximately 250 hosts per subnet, with around 2,000 hosts

in a large data center LAN. If we are to consider those 2,000 servers with 5:1 virtual server density, this translates to

10,000 IP addresses and 10,000 MAC addresses. The scalability of the EX4200 Series Ethernet switches with Virtual

Chassis technology easily meets the need of these dense environments with large route and MAC address tables and

scalable wire-speed performance.

The granular QoS capabilities of the Juniper Networks EX Series switches, with eight queues per port, also enables

differing QoS policies to be set per virtual operating system and application.

Figure 7: Virtualized server infrastructure

Connectivity

Properly accounting for the required number of high-speed wired access ports for servers and storage devices as

well as all aggregation layer connections in the data center is vital. Not only must the port density be specified,

but the appropriate number of GbE and 10 GbE ports must also be taken into consideration. It’s also important to

account for any WLAN access points, IP phones, CCTV cameras and other IP devices the data center must directly

support when addressing port requirements. The logical segmentation required and the number of logically separate

networks that should share the same LAN must also be determined. These considerations help establish what type

of hardware configuration is needed.

Power over Ethernet (PoE)

Most highly available data center facilities will have WLAN access points, IP phones, security cameras and other IP-

based office automation peripherals, many of which require PoE to function. Accounting for the correct number and

location of PoE ports needed in the data center is important at the access layer.

High Availability (HA)

Since the data center servers connected at the access layer are utilized by all throughout the enterprise, it’s

critical that data center networks operate with maximum reliability and uptime. The following levels of HA may be

implemented in the data center:

L2/L3 SwitchL2/L3 Switch

App