Storage Provisioning and Networking - Deploying and Managing a Cloud Infrastructure - page 259

Layer (Higher Is
More Abstract) Name Protocols/Examples

5 Session SDP, SOCKS, NetBIOS

4 Transport T C P, U D P

3 Network IPv4/IPv6 (Subnets are constructed from

IP addresses.), ICMP, ARP, IPSec

2 Data-Link Ethernet (VLANs are constructed over

Ethernet.), PPP

1 Physical DSL, ISDN, USB, IRDA

A VLAN has the same attributes as the physical LAN, but the advantage is that it allows
for end stations to be grouped across network switches. Organizations utilize the VLANs
to avoid the trouble of going through physical allocation and reallocation of devices and
connections in an internal network.
Organizations also partition a local network into distinctive segments to maintain
segregation, a high level of security, proxy enabling, and great flexibility. For example, a
production network has distinct availability requirements that are different than those of
a guest network, and Quality of Service (QoS) schemes can optimize traffic on links for
real-time traffic (VoIP) or low-latency requirements (SAN).

Network Optimization

Network optimization typically refers to the processes and tools that help a network
administrator operate an enterprise network at peak efficiency. This includes keeping
the physical infrastructure, such as routers and switches, up-to-date with latest security
patches. One important task is to resolve data flow bottlenecks. Network optimization
helps administrators maintain service-level agreements (SLAs).
There are two critical parts of network optimization: network planning and network
operations, as described in the following sections.

Network Planning
Network planning involves designing the network according to the requirements of the
business or enterprise, such as, for instance, LAN deployments for office spaces, MAN
deployments to connect multiple offices over the same citywide area, and WAN deploy-
ments for connecting countrywide or continent-wide regions. The administrator has
to think about effective VPN-enabled connectivity across the board for each type of
deployment.