Cisco Prime IP Express is a full featured, scalable Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP)
implementation for medium to large IP networks. It provides the key benefits of stabilizing the IP infrastructure and automating networking services, such as configuring
clients and provisioning cable modems. This provides a foundation for policy-based networking.
Enterprise users can better manage their networks to integrate with other network infrastructure software and business applications.
IP Express is designed for these users:
Enterprises —Helps meet the needs of single-
and multisite enterprises (small-to-large businesses) to administer and control
network functions. Cisco Prime
IP Express automates the tasks of assigning
IP addresses and configuring the Transport Control Protocol/Internet Protocol
(TCP/IP) software for individual network devices. Forward-looking enterprise
users can benefit from class-of-service and other features that help integrate
with new or existing network management applications, such as user
Regional and Local
The regional cluster
acts as an aggregate management system for up to a hundred local clusters.
Address and server administrators interact at the regional and local clusters
through the regional and local web-based user interfaces (web UIs), and local
cluster administrators can continue to use the command line interface (CLI) at
the local cluster. The regional cluster consists of a Central Configuration
Management (CCM) server, Tomcat web server, servlet engine, and server agent
The license management is now done at the regional cluster and hence the local
server has to be registered to a regional server to avail the necessary
services. See the
Installation Guide for more details.
A typical deployment
is one regional cluster at a customer network operation center (NOC), the
central point of network operations for an organization. Each division of the
organization includes a local address management server cluster responsible for
managing a part of the network. The System Configuration Protocol (SCP)
communicates the configuration changes between the servers.
The Cisco Prime
IP Express regional cluster web UI provides
a single point to manage any number of local clusters hosting DNS, CDNS,
or DHCP servers. The regional and local
clusters also provide administrator management so that you can assign
administrative roles to users logged in to the application.
This section describes two basic administrative scenarios and the
hardware and software deployments for two different types of installations—a
small-to-medium local area network (LAN), and a large-enterprise or
service-provider network with three geographic locations.
In this scenario,
low-end Windows or Linux servers are acceptable. The image below shows a
configuration that would be adequate for this network.
Regional server is
MUST in deployment for small and medium sized LANs.
In a large enterprise
network serving over 500,000 DHCP clients, use mid-range Windows or
Linux servers. Put DNS and DHCP servers on different systems. The image below
shows the hardware that would be adequate for this network.
geographically dispersed clients, locate DHCP servers at remote locations to
avoid disrupting local services if wide-area connections fail. Install the
IP Express regional cluster to centrally manage the
IP Express is an integrated DHCP and DNS server cluster
capable of running on a Windows or Linux workstation or server.
Because of the wide
range of network topologies for which you can deploy Cisco Prime
IP Express, you should first consider the following
guidelines. These guidelines are very general and cover most cases. Specific or
challenging implementations could require additional hardware or servers.
The following suggestions apply to most Cisco Prime
IP Express deployments:
Configure a separate DHCP
server to run in remote segments of the wide area network (WAN).
Ensure that the DHCP client can consistently send a packet to the
server in under a second. The DHCP protocol dictates that the client receive a
response to a DHCPDISCOVER or DHCPREQUEST packet within four seconds of
transmission. Many clients (notably early releases of the Microsoft DHCP stack)
actually implement a two-second timeout.
In large deployments,
separate the secondary DHCP server from the primary DNS server used for dynamic
Because lease requests and dynamic DNS updates are persisted to
disk, server performance is impacted when using a common disk system. So that
the DNS server is not adversely affected, run it on a different cluster than
the DHCP server.
Include a time server in
your configuration to deal with time differences between the local and regional
clusters so that aggregated data at the regional server appears in a consistent
way. See the
Polling Lease History Data.
Set DHCP lease times in
policies to four to ten days.
To prevent leases from expiring when the DHCP client is turned off
(overnight or over long weekends), set the DHCP lease time longer than the
longest period of expected downtime, such as seven days. See
"Managing Leases" section inCisco Prime
IP Express 9.0 DHCP User
Locate backup DNS servers
on separate network segments.
DNS servers are redundant by nature. However, to minimize client
impact during a network failure, ensure that primary and secondary DNS servers
are on separate network segments.
If there are high dynamic
DNS update rates in the network, configure separate DNS servers for forward and
Secondary DNS servers can receive their data from the primary DNS
server in two ways: through a full zone transfer (AXFR) or an incremental zone
transfer (NOTIFY/IXFR, as described in RFCs 1995 and 1996). Use NOTIFY/IXFR in
environments where the name space is relatively dynamic. This reduces the
number of records transferred from the primary to the secondary server. See the
"Enabling Incremental Zone Transfers (IXFR)” section in
IP Express 9.0
Authoritative and Caching DNS User Guide.
suggestions apply to some special configurations:
When using dynamic DNS
updates for large deployments or very dynamic networks, divide primary and
secondary DNS and DHCP servers across multiple clusters.
updates generate an additional load on all Cisco Prime IP Express
servers as new DHCP lease requests trigger dynamic DNS updates to primary
servers that update secondary servers through zone transfers.
reconfiguration, set DHCP lease renewal times to a small value.
Do this several
days before making changes in network infrastructure (such as to gateway router
and DNS server addresses). A renewal time of eight hours ensures that all DHCP
clients receive a changed DHCP option parameter within one working day. See the
"Managing Leases" section inCisco Prime
IP Express 9.0
Authoritative and Caching DNS User Guide
For Cisco Prime
IP Express, the general guideline is to
invest in the highest performance disk I/O subsystem available, then memory,
and finally the processors. DHCP and Authoritative DNS (especially if using DNS
updates) will be most impacted by disk latency, then memory and network
performance, and finally CPU (these applications are not CPU intensive).
The best way to
reduce latency and improve performance is to provide high performance disks
(SSD are recommended over traditional hard disks). High performance disk
controllers are also recommended. This is especially important for DHCP and
Authoritative DNS servers that handle Dynamic Updates.
Providing lots of
memory is also important as it reduces disk read requirements if the file
system cache can be used. The recommendation here is to assure that a system
has sufficient free memory that is twice the size of the
CPIPEdatabases. It is difficult to give
exact requirements here as it depends on many variables.
performance is also an important consideration and 1 GB or better Ethernet
controllers are recommended.
As most Cisco
IP Express uses are not CPU intensive, the
CPU performance tends to be least important.
with Earlier Releases
The following table
shows the interoperability of Cisco Prime Network Registrar / Cisco Prime IP Express features on the regional CCM
server with versions of the local cluster.
Table 1. CCM Regional
Feature Interoperability with Server Versions