CH A P T E R
IP Multicast in a Data Center
Because many of the servers residing in the data center may use multicast to communicate, it becomes necessary to enable IP multicasting on the data center switches. Platforms that deliver video services, such as Cisco’s IP/TV broadcast servers, rely on multicast to deliver their services to end users. Many back-end applications use multicast for replication purposes.
This chapter provides an overview of the data center architecture and recommendations for implementing IP multicast in the data center. For more information about designing data centers, see the Designing Enterprise Data Centers Solution Reference Network Design guide.
Data Center Architecture Overview
As with the campus network, the data center uses a hierarchical architecture composed of layers. The layers of a data center are:
Aggregation Layer Front-End Layer Application Layer Back-End Layer Storage Layer
The aggregation layer consists of network infrastructure components and other devices supporting application, security, and management services. The aggregation layer is analogous to the traditional distribution layer in the campus network in its Layer 3 and Layer 2 functionality. Those services that are common to the devices in the front-end layer and the layers behind it should be centrally located for consistency, manageability, and predictability. This makes the aggregation layer the location where services are centralized. The devices in this layer include aggregation switches that connect the server farms to the core layer, content switches, firewalls, intrusion detection systems (IDSs), content engines, and SSL offloading.
For IP multicast: The aggregation layer requires multicast routing with PIM Sparse-mode to be configured.
The Layer 3 switches in the aggregation layer point to the RPs previously defined in the campus core.
Cisco AVVID Network Infrastructure IP Multicast Design