openstack-manuals/doc/arch-design/ch_network_focus.xml
Graeme Gillies b8024e511b First overview and cleanup of network focused chapter
This is a removal of out of date information from the guide
as well as removing the sections being moved into common

Change-Id: I4dc89ddaaf6d0e2338852d37fecf61a6eeb73a30
Implements: blueprint arch-guide
2015-08-13 14:05:58 +10:00

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