Data Center LAN Migration Guide - Juniper Networks

Data Center LAN Migration Guide
Network topologies should mirror
the nature of the tra�c they transport
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UP TO 70%
Figure 3: Data center traffic flows
Applications built on SOA architecture and those delivered in the software as a service (SaaS) model require an
increasing number of interactions among servers in the data center. These technologies generate a significant amount of
server-to-server traffic; in fact, up to 70% of data center LAN traffic is between servers. Additional server traffic may also
be produced by the increased adoption of virtualization, where shared resources such as a server pool are used at greater
capacity to improve efficiency. Today’s network topologies need to mirror the nature of the traffic being transported.
Existing three-tier architectures were not designed to handle server-to-server traffic without going up and back through
the many layers of tiers. This is inherently inefficient, adding latency at each hop, which in turn impacts performance,
particularly for real-time applications like unified communications, or in industries requiring high performance such as
financial trading.
Scaling Is Too Complex with Current Data Center Architectures
Simply deploying ever more servers, storage, and devices in a three-tier architecture to meet demand significantly
increases network complexity and cost. In many cases, it isn’t possible to add more devices due to space, power,
cooling, or throughput constraints. And even when it is possible, it is often difficult and time-consuming to manage due
to the size and scope of the network. Or it is inherently inefficient, as it’s been estimated that as much as 50% of all
ports in a typical data center are used for connecting switches to each other as opposed to doing the more important
task of interconnecting storage to servers and applications to users. Additionally, large Layer 2 domains using Spanning
Tree Protocol (STP) are prone to failure and poor performance. This creates barriers to the efficient distribution of
resources in the DC and fundamentally prevents a fast and flexible network scale out. Similarly, commonly deployed
data center technologies like multicast don’t perform at scale across tiers and devices in a consistent fashion.
Legacy security services may not easily scale and are often not efficiently deployed in a data center LAN due to the
difficulty of incorporating security into a legacy,multitiered design. Security blades which are bolted into switches at the
aggregation layer consume excessive power and space, impact performance, and don’t protect virtualized resources.
Another challenge of legacy security service appliances is the limited performance scalability, which may be far
below the throughput requirements of most high-performance enterprises consolidating applications or data centers.
The ability to cluster together firewalls as a single logical entity to increase scalability without added management
complexity is another important consideration.
Proprietary systems may also limit further expansion with vendor lock-in to low performance equipment. Different
operating systems at each layer may add to the complexity to operate and scale the network. This complexity is costly,
limits flexibility, increases the time it takes to provision new capacity or services, and restricts the dynamic allocation of
resources for services such as virtualization.
10 Copyright © 2012, Juniper Networks, Inc.
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