Data Center LAN Migration Guide - Juniper Networks

Data Center LAN Migration Guide
Figure 13 below depicts an EX4200 Virtual Chassis top-of-rack access layer deployment.
TOR DEPLOYMENT
L2/L3 Switch
Access Layer Preinstallation Tasks
L2/L3 Switch
EX4200 Virtual Chassis EX4200
Virtual Chassis
Figure 14: EX4200 top-of-rack access layer deployment
Legacy Aggregation Layer
Access Layer
• One of the first tasks is to determine space requirements for the new equipment. If the new access layer switches are
to be housed in new racks, make sure that there is adequate space for the racks in the POD or data center. Or, if it is
a switch refresh, ensure that there is sufficient space in the existing racks to accommodate the new switches. If the
existing racks have the capacity, the eventual switchover becomes a matter of simply switching server cables from
the old switches to the new ones. New racks are usually involved when a server refresh is combined with a switch
refresh. It is assumed that data center facilities already have the power, cooling, airflow, and cabling required for any
new equipment being provisioned.
• In a top-of-rack configuration, the EX4200 with Virtual Chassis technology can be logically viewed as a single
chassis horizontally deployed across racks. It is important to understand the traffic profiles, since this determines the
number of required uplinks. If the traffic flows are predominantly between servers, often referred to as “east-west”
traffic, fewer uplinks to the core network layer are required since inter-server traffic primarily traverses the Virtual
Chassis’ 128 Gbps backplane. The number of uplinks required is also a function of acceptable oversubscription
ratios, which can be easily tuned as per the Virtual Chassis Best Practices section. The EX4200 with Virtual Chassis
technology may also be used in an end-of-row deployment taking these same considerations into account.
• When connecting to an existing non-Juniper aggregation layer switch, it’s important to use open standard protocols
such as 802.1Q for trunking VLANs and Multiple VLAN Registration Protocol (MVRP) if VLAN propagation is desired.
To ensure interoperability, one of the standards-based STPs (IEEE STP, Rapid Spanning Tree Protocol, or Multiple
Spanning Tree Protocol) should also be used.
• If they exist, company standard IOS-based access layer configurations should be collected. They can be quickly and
easily converted into Junos OS using Juniper’s I2J translation tool as previously described.
• To simplify the deployment process and ensure consistent configurations when installing multiple access layer
switches, Junos OS automation tools such as AutoInstall may be used. Refer to the following for more information:
www.juniper.net/techpubs/software/junos-security/junos-security96/junos-security-admin-guide/configautoinstall-chapter.html.
• To further save time and ensure consistency, configuration files may be generated in advance, and then uploaded to
a Trivial File Transfer Protocol (TFTP)/HTTP or FTP server for later downloading. The operations support systems
(OSS) in place for switch provisioning and configuration management determine the type of server to use.
• To test feature consistency and feature implementations for the new Juniper access layer switches, a proof-ofconcept
(PoC) lab could be set up, as previously noted. Feature and compatibility testing is greatly reduced with a
single OS across all platforms such as Junos OS, which maintains a strict, serial release cycle. Feature testing in a
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