153 lines
7.5 KiB
XML
153 lines
7.5 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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version="5.0"
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xml:id="network_focus">
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<title>Network focused</title>
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<para>All OpenStack deployments depend on network communication in order
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to function properly due to its service-based nature. In some cases,
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however, the network elevates beyond simple
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infrastructure. This chapter discusses architectures that are more
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reliant or focused on network services. These architectures depend
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on the network infrastructure and require
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network services that perform reliably in order to satisfy user and
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application requirements.</para>
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<para>Some possible use cases include:</para>
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<variablelist>
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<varlistentry>
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<term>Content delivery network</term>
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<listitem>
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<para>This includes streaming video, viewing photographs, or
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accessing any other cloud-based data repository distributed to
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a large number of end users. Network configuration affects
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latency, bandwidth, and the distribution of instances. Therefore,
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it impacts video streaming. Not all video streaming is
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consumer-focused. For example, multicast videos (used for media,
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press conferences, corporate presentations, and web conferencing
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services) can also use a content delivery network.
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The location of the video repository and its relationship to end
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users affects content delivery. Network throughput of the back-end
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systems, as well as the WAN architecture and the cache methodology,
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also affect performance.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Network management functions</term>
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<listitem>
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<para>Use this cloud to provide network service functions built to
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support the delivery of back-end network services such as DNS,
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NTP, or SNMP.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Network service offerings</term>
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<listitem>
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<para>Use this cloud to run customer-facing network tools to
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support services. Examples include VPNs, MPLS private networks,
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and GRE tunnels.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Web portals or web services</term>
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<listitem>
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<para>Web servers are a common application for cloud services,
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and we recommend an understanding of their network requirements.
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The network requires scaling out to meet user demand and deliver
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web pages with a minimum latency. Depending on the details of
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the portal architecture, consider the internal east-west and
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north-south network bandwidth.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>High speed and high volume transactional systems</term>
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<listitem>
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<para>
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These types of applications are sensitive to network
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configurations. Examples include financial systems,
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credit card transaction applications, and trading and other
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extremely high volume systems. These systems are sensitive
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to network jitter and latency. They must balance a high volume
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of East-West and North-South network traffic to
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maximize efficiency of the data delivery.
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Many of these systems must access large, high performance
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database back ends.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>High availability</term>
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<listitem>
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<para>These types of use cases are dependent on the proper sizing
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of the network to maintain replication of data between sites for
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high availability. If one site becomes unavailable, the extra
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sites can serve the displaced load until the original site
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returns to service. It is important to size network capacity
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to handle the desired loads.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Big data</term>
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<listitem>
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<para>Clouds used for the management and collection of big data
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(data ingest) have a significant demand on network resources.
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Big data often uses partial replicas of the data to maintain
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integrity over large distributed clouds. Other big data
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applications that require a large amount of network resources
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are Hadoop, Cassandra, NuoDB, Riak, and other NoSQL and
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distributed databases.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Virtual desktop infrastructure (VDI)</term>
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<listitem>
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<para>This use case is sensitive to network congestion, latency,
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jitter, and other network characteristics. Like video streaming,
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the user experience is important. However, unlike video
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streaming, caching is not an option to offset the network issues.
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VDI requires both upstream and downstream traffic and cannot rely
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on caching for the delivery of the application to the end user.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Voice over IP (VoIP)</term>
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<listitem>
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<para>This is sensitive to network congestion, latency, jitter,
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and other network characteristics. VoIP has a symmetrical traffic
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pattern and it requires network quality of service (QoS) for best
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performance. In addition, you can implement active queue management
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to deliver voice and multimedia content. Users are sensitive to
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latency and jitter fluctuations and can detect them at very low
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levels.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Video Conference or web conference</term>
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<listitem>
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<para>This is sensitive to network congestion, latency, jitter,
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and other network characteristics. Video Conferencing has a
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symmetrical traffic pattern, but unless the network is on an
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MPLS private network, it cannot use network quality of service
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(QoS) to improve performance. Similar to VoIP, users are
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sensitive to network performance issues even at low levels.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>High performance computing (HPC)</term>
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<listitem>
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<para>This is a complex use case that requires careful
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consideration of the traffic flows and usage patterns to address
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the needs of cloud clusters. It has high east-west traffic
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patterns for distributed computing, but there can be substantial
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north-south traffic depending on the specific application.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<xi:include href="network_focus/section_user_requirements_network_focus.xml"/>
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<xi:include href="network_focus/section_tech_considerations_network_focus.xml"/>
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<xi:include href="network_focus/section_operational_considerations_network_focus.xml"/>
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<xi:include href="network_focus/section_architecture_network_focus.xml"/>
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<xi:include href="network_focus/section_prescriptive_examples_network_focus.xml"/>
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</chapter>
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