Cisco ISE architecture includes the following components:
Nodes and persona types
Cisco ISE node—A Cisco ISE node can assume any or all of the
following personas: Administration, Policy Service, Monitoring, or pxGrid
The policy information point represents the point at which
external information is communicated to the Policy Service persona. For
example, external information could be a Lightweight Directory Access Protocol
Cisco ISE Deployment
This guide uses the following terms when discussing Cisco ISE
A specific feature that a persona provides such as network
access, profiling, posture, security group access, monitoring, and
An individual physical or virtual Cisco ISE appliance.
The Cisco ISE node can assume any of the following
personas: Administration, Policy Service, Monitoring
Determines the services provided by a node. A Cisco ISE node can
assume any or all of the following personas:
. The menu options that are
available through the administrative user interface depend on the role and
personas that a node assumes.
Determines if a node is a standalone, primary, or secondary node
and applies only to Administration and Monitoring nodes.
Node Types and
Personas in Distributed Deployments
A Cisco ISE node can provide various services based on the persona that it assumes. Each node in a deployment can assume the
Administration, Policy Service, pxGrid, and Monitoring personas. In a distributed deployment, you can have the following combination
of nodes on your network:
Primary and secondary Administration nodes for high availability
A pair of Monitoring nodes for automatic failover
One or more Policy Service nodes for session failover
One or more pxGrid nodes for pxGrid services
A Cisco ISE node with the Administration persona
allows you to perform all administrative operations on Cisco ISE. It handles
all system-related configurations that are related to functionality such as
authentication, authorization, and accounting. In a distributed deployment, you
can have a maximum of two nodes running the Administration persona. The
Administration persona can take on the standalone, primary, or secondary role.
A Cisco ISE node with the Policy Service persona provides
network access, posture, guest access, client provisioning, and profiling
services. This persona evaluates the policies and makes all the decisions. You
can have more than one node assume this persona. Typically, there would be more
than one Policy Service node in a distributed deployment. All Policy Service
nodes that reside in the same high-speed Local Area Network (LAN) or behind a
load balancer can be grouped together to form a node group. If one of the nodes
in a node group fails, the other nodes detect the failure and reset any
At least one node in your distributed setup should assume the
Policy Service persona.
A Cisco ISE node with the Monitoring persona
functions as the log collector and stores log messages from all the
Administration and Policy Service nodes in a network. This persona provides
advanced monitoring and troubleshooting tools that you can use to effectively
manage a network and resources. A node with this persona aggregates and
correlates the data that it collects, and provides you with meaningful reports.
Cisco ISE allows you to have a maximum of two nodes with this persona, and they
can take on primary or secondary roles for high availability. Both the primary
and secondary Monitoring nodes collect log messages. In case the primary
Monitoring node goes down, the secondary Monitoring node automatically becomes
the primary Monitoring node.
At least one node in your distributed setup should
assume the Monitoring persona. We recommend that you do not have the Monitoring
and Policy Service personas enabled on the same Cisco ISE node. We recommend
that the Monitoring node be dedicated solely to monitoring for optimum
You can use Cisco
pxGrid to share the context-sensitive information from Cisco ISE session
directory with other network systems such as ISE Eco system partner systems and
other Cisco platforms. The pxGrid framework can also be used to exchange policy
and configuration data between nodes like sharing tags and policy objects
between Cisco ISE and third party vendors, and for other information exchanges.
Cisco pxGrid also allows third party systems to invoke adaptive network control
actions (EPS) to quarantine users/devices in response to a network or security
event. The TrustSec information like tag definition, value, and description can
be passed from Cisco ISE via TrustSec topic to other networks. The endpoint
profiles with Fully Qualified Names (FQNs) can be passed from Cisco ISE to
other networks through a endpoint profile meta topic. Cisco pxGrid also
supports bulk download of tags and endpoint profiles.
You can publish and
subscribe to SXP bindings (IP-SGT mappings) through pxGrid. For more
information about SXP bindings, see Source Group Tag Protocol section in
Cisco Identity Services Engine Administrator Guide.
In a high-availability
configuration, Cisco pxGrid servers replicate information between the nodes
through the PAN. When the PAN goes down, pxGrid server stops handling the
client registration and subscription. You need to manually promote the PAN for
the pxGrid server to become active.
Distributed ISE Deployments
A deployment that has a single Cisco ISE node is called a
standalone deployment. This node runs the Administration,
Policy Service, and Monitoring personas.
A deployment that has more than one Cisco ISE node is called a
distributed deployment. To support failover and to improve
performance, you can set up a deployment with multiple Cisco ISE nodes in a
distributed fashion. In a Cisco ISE distributed deployment, administration and
monitoring activities are centralized, and processing is distributed across the
Policy Service nodes. Depending on your performance needs, you can scale your
deployment. A Cisco ISE node can assume any of the following personas:
Administration, Policy Service, and Monitoring.
Distributed Deployment Scenarios
Small Network Deployments
Medium-Sized Network Deployments
Large Network Deployments
Small Network Deployments
The smallest Cisco ISE deployment consists of two
Cisco ISE nodes with one Cisco ISE node functioning as the primary appliance in
a small network.
The primary node provides all the configuration,
authentication, and policy capabilities that are required for this network
model, and the secondary Cisco ISE node functions in a backup role. The
secondary node supports the primary node and maintains a functioning network
whenever connectivity is lost between the primary node and network appliances,
network resources, or RADIUS.
Centralized authentication, authorization, and accounting (AAA) operations between clients and the primary Cisco ISE node
are performed using the RADIUS protocol. Cisco ISE synchronizes or replicates all of the content that resides on the primary
Cisco ISE node with the secondary Cisco ISE node. Thus, your secondary node is current with the state of your primary node.
In a small network deployment, this type of configuration model allows you to configure both your primary and secondary nodes
on all RADIUS clients by using this type of deployment or a similar approach.
As the number of devices, network resources, users, and AAA clients increases in your network environment, you should change
your deployment configuration from the basic small model and use more of a split or distributed deployment model.
In split Cisco ISE deployments, you continue to
maintain primary and secondary nodes as described in a small Cisco ISE
deployment. However, the AAA load is split between the two Cisco ISE nodes to
optimize the AAA workflow. Each Cisco ISE appliance (primary or secondary)
needs to be able to handle the full workload if there are any problems with AAA
connectivity. Neither the primary node nor the secondary nodes handles all AAA
requests during normal network operations because this workload is distributed
between the two nodes.
The ability to split the load in this way directly
reduces the stress on each Cisco ISE node in the system. In addition, splitting
the load provides better loading while the functional status of the secondary
node is maintained during the course of normal network operations.
In split Cisco ISE deployments, each node can
perform its own specific operations, such as network admission or device
administration, and still perform all the AAA functions in the event of a
failure. If you have two Cisco ISE nodes that process authentication requests
and collect accounting data from AAA clients, we recommend that you set up one
of the Cisco ISE nodes to act as a log collector.
In addition, the split Cisco ISE deployment design
provides an advantage because it allows for growth.
Medium-Sized Network Deployments
As small networks grow, you can keep pace and
manage network growth by adding Cisco ISE nodes to create a medium-sized
network. In medium-sized network deployments, you can dedicate the new nodes
for all AAA functions, and use the original nodes for configuration and logging
In a medium-sized network deployment, you cannot enable the Policy Service persona on a node that runs the Administration
persona, Monitoring persona, or both. You need dedicated policy service node(s).
As the amount of log traffic increases in a
network, you can choose to dedicate one or two of the secondary Cisco ISE nodes
for log collection in your network.
Large Network Deployments
We recommend that you use centralized logging for
large Cisco ISE networks. To use centralized logging, you must first set up a
dedicated logging server that serves as a Monitoring persona (for monitoring
and logging) to handle the potentially high syslog traffic that a large, busy
network can generate.
Because syslog messages are generated for outbound
log traffic, any RFC 3164-compliant syslog appliance can serve as the collector
for outbound logging traffic. A dedicated logging server enables you to use the
reports and alert features that are available in Cisco ISE to support all the
Cisco ISE nodes.
You can also consider having the appliances send
logs to both a Monitoring persona on the Cisco ISE node and a generic syslog
server. Adding a generic syslog server provides a redundant backup if the
Monitoring persona on the Cisco ISE node goes down.
In large centralized networks, you should use a
load balancer, which simplifies the deployment of AAA clients. Using a load
balancer requires only a single entry for the AAA servers, and the load
balancer optimizes the routing of AAA requests to the available servers.
However, having only a single load balancer
introduces the potential for having a single point of failure. To avoid this
potential issue, deploy two load balancers to ensure a measure of redundancy
and failover. This configuration requires you to set up two AAA server entries
in each AAA client, and this configuration remains consistent throughout the
Dispersed Network Deployments
Dispersed Cisco ISE network deployments are most
useful for organizations that have a main campus with regional, national, or
satellite locations elsewhere. The main campus is where the primary network
resides, is connected to additional LANs, ranges in size from small to large,
and supports appliances and users in different geographical regions and
Large remote sites can have their own AAA
infrastructure for optimal AAA performance. A centralized management model
helps maintain a consistent, synchronized AAA policy. A centralized
configuration model uses a primary Cisco ISE node with secondary Cisco ISE
nodes. We still recommend that you use a separate Monitoring persona on the
Cisco ISE node, but each remote location should retain its own unique network
Considerations for Planning a Network with Several Remote
Verify if a central or external database is
used, such as Microsoft Active Directory or Lightweight Directory Access
Protocol (LDAP). Each remote site should have a synchronized instance of the
external database that is available for Cisco ISE to access for optimizing AAA
The location of AAA clients is important.
You should locate the Cisco ISE nodes as close as possible to the AAA clients
to reduce network latency effects and the potential for loss of access that is
caused by WAN failures.
Cisco ISE has console access for some
functions such as backup. Consider using a terminal at each site, which allows
for direct, secure console access that bypasses network access to each node.
If small, remote sites are in close
proximity and have reliable WAN connectivity to other sites, consider using a
Cisco ISE node as a backup for the local site to provide redundancy.
Domain Name System (DNS) should be properly
configured on all Cisco ISE nodes to ensure access to the external databases.
Maximum Supported Sessions for Each Deployment Model
The following tables list the maximum supported sessions for each deployment model.
Table 1. Maximum Supported Sessions per Deployment Model
Standalone (All personas on a single node)
Basic 2-node deployment (redundant)
Hybrid-Distributed deployment (Admin and MnT on same appliance; Policy Service on dedicated appliance)
1 Dedicated Policy nodes (Max sessions gated by Total Deployment size)
Switch and Wireless LAN Controller Configuration Required to Support
Cisco ISE Functions
To ensure that Cisco ISE can interoperate with
network switches and that functions from Cisco ISE are successful across the
network segment, you must configure your network switches with certain required
Network Time Protocol (NTP), RADIUS/AAA, IEEE 802.1X, MAC Authentication Bypass
(MAB), and other settings.