This document describes how to configure Device Sensor, so that it can be used for profiling purposes on ISE. Device sensor is a feature of access devices. It allows to collect information about connected endpoints. Mostly, information collected by Device Sensor can come from the following protocols:
Cisco Discovery Protocol (CDP)
Link Layer Discovery Protocol (LLDP)
Dynamic Host Configuration Protocol (DHCP)
On some platforms it is possible to use also H323, SIP (Session Initiation Protocol), MDNS (Multicast Domain Resolution) or HTTP protocols. Configuration possibilities for device sensor capabilities can vary from protocol to protocol. As an example above is available on Cisco Catalyst 3850 with software 03.07.02.E.
Once the information is collected, it can be encapsulated in radius accounting and send to a profiling server. In this article Identity Service Engine (ISE) is used as a profiling server.
Cisco recommends that you have knowledge of these topics:
CDP, LLDP and DHCP protocols
Cisco Identity Service Engine
Cisco Catalyst Switch 2960
The information in this document is based on these software and hardware versions:
Cisco Identity Service Engine version 1.3 patch 3
Cisco Catalyst Switch 2960s version 15.2(2a)E1
Cisco IP Phone 8941 version SCCP 9-3-4-17
Step 1. Standard AAA configuration
In order to configure Authentication, Authorization and Accounting (AAA), follow the steps below:
1. Enable AAA using aaa new-model command and enable 802.1X globally on the switch
2. Configure Radius server and enable dynamic authorization (Change of Authorization - CoA)
3. Enable CDP and LLDP protocols
4. Add switchport authentication configuration
! aaa new-model
aaa authentication dot1x default group radius
aaa authorization network default group radius
aaa accounting update newinfo
aaa accounting dot1x default start-stop group radius
! aaa server radius dynamic-author client 18.104.22.168 server-key xyz ! dot1x system-auth-control !
lldp run cdp run
switchport mode access
switchport voice vlan 101
authentication event fail action next-method
authentication host-mode multi-domain
authentication order dot1x mab
authentication priority dot1x mab
authentication port-control auto
dot1x pae authenticator
dot1x timeout tx-period 2
radius-server host 22.214.171.124 auth-port 1812 acct-port 1813 key xyz !
In newer software version command radius-server vsa send accounting is enabled by default. If you cannot see attributes send in accounting, verify if the command in enabled.
Step 2. Configure Device Sensor
1. Determine which attributes from CDP/LLDP are needed to profile the device. In case of Cisco IP Phone 8941 you can use the following:
LLDP SystemDescription attribute
CDP CachePlatform attribute
For our purpose it would be enough to obtain just one of those since both of them provide Certainty Factory increase of 70 and Minimum Certainty Factory required to be profiled as Cisco-IP-Phone-8941 is 70:
In order to be profiled as specific Cisco IP Phone, youneed to satisfy minimum conditions for all parent profiles. This means profiler needs to match Cisco-Device (min. Certainty Factor 10) and Cisco-IP-Phone (min. Certainty Factor 20). Even though profiler matches those two profiles, it should still be profiled as specific Cisco IP Phone since each IP Phone model has min. Certainty Factor of 70. Device is assigned to the profile for which it has highest Certainty Factor.
2. Configure two filter lists - one for CDP and another one for LLDP. Those indicate which attributes should be included in Radius accounting messages. This step is optional
3. Create two filter-specs for CDP and LLDP. In fiter spec you can either indicate that list of attributes should be included or excluded from accounting messages. In the example following attributes are included:
device-name from CDP
system-description from LLDP
You can configure additional attributes to be transmited via Radius to ISE if needed. This step is also optional.
4. Add command device-sensor notify all-changes. It triggers updates whenever TLVs are added, modified or removed for current session
5. In order to actually send the information gathered via Device Sensor functionality, you need to explicitly tell the switch to do so with command device-sensor accounting
device-sensor filter-list cdp list cdp-list
tlv name device-name tlv name platform-type
device-sensor filter-list lldp list lldp-list
tlv name system-description
device-sensor filter-spec lldp include list lldp-list
device-sensor filter-spec cdp include list cdp-list
device-sensor notify all-changes
Step 3. Configure profiling on ISE
1. Add switch as a network device in "Administration>Network Resources>Network Devices". Use the radius server key from the switch as shared secret in Authentication Settings:
2. Enable Radius probe on the profiling node in "Administration>System>Deployment>ISE node>Profiling Configuration". If all PSN nodes should be used for profiling, enable the probe on all of them:
3. Configure ISE Authentication Rules. In the example the default authentication rules preconfigured on ISE are used:
4. Configure ISE Authorization Rules. 'Profiled Cisco IP Phones' rule is used, which is preconfigured on ISE:
In order to verify if profiling is working correctly, please refer to "Operations>Authentications" on ISE:
First the device was authenticated using MAB (18:49:00). Ten seconds later (18:49:10) it was reprofiled as Cisco-Device and finaly after 42 seconds since first authentications (18:49:42) it received Cisco-IP-Phone-8941 profile. As a result ISE returns Authorization Profile specific for IP Phones (Cisco_IP_Phones) and Downloadable ACL that permits all traffic (permit ip any any). Please note that in this scenario the unknown device has basic access to the network. It can be achieved by adding mac address to ISE internal endpoint database or allowing very basic network access for previously unknown devices.
Initial profiling took around 40 seconds in this example. On the next authentication ISE already knows the profile and correct attributes (permission to join voice domain and DACL) are applied instantly, unless ISE receives new/updated attributes and it needs to reprofile the device again.
In "Administration>Identity Management>Identities>Endpoints>tested endpoint" you can see what kind of attributes were collected by Radius probe and what their values are:
As you can observe the total Certainty Factor computed is 210 in this scenario. It comes fromt the fact that endpoint matched also Cisco-Device profile (with total certainty factor of 30) and Cisco-IP-Phone profile (with total certainty factor of 40). Since profiler matched both conditions in profile Cisco-IP-Phone-8941, certainty factor for this profile is 140 (70 for each attribute according to profiling policy). To sum up: 30+40+70+70=210.
Step 1. Verify information collected by CDP/LLDP
switch#sh cdp neighbors g1/0/13 detail
Device ID: SEP20BBC0DE06AE
Platform: Cisco IP Phone 8941 , Capabilities: Host Phone Two-port Mac Relay
Interface: GigabitEthernet1/0/13, Port ID (outgoing port): Port 1
Holdtime : 178 sec
Second Port Status: Down
advertisement version: 2
Power drawn: 3.840 Watts
Power request id: 57010, Power management id: 3
Power request levels are:3840 0 0 0 0
Total cdp entries displayed : 1
switch# switch#sh lldp neighbors g1/0/13 detail ------------------------------------------------ Chassis id: 0.0.0.0 Port id: 20BBC0DE06AE:P1 Port Description: SW Port System Name: SEP20BBC0DE06AE.
System Description: Cisco IP Phone 8941, V3, SCCP 9-3-4-17
Time remaining: 164 seconds System Capabilities: B,T Enabled Capabilities: B,T Management Addresses - not advertised Auto Negotiation - supported, enabled Physical media capabilities: 1000baseT(FD) 100base-TX(FD) 100base-TX(HD) 10base-T(FD) 10base-T(HD) Media Attachment Unit type: 16 Vlan ID: - not advertised
MED Codes: (NP) Network Policy, (LI) Location Identification (PS) Power Source Entity, (PD) Power Device (IN) Inventory
H/W revision: 3 F/W revision: 0.0.1.0 S/W revision: SCCP 9-3-4-17 Serial number: PUC17140FBO Manufacturer: Cisco Systems , Inc. Model: CP-8941 Capabilities: NP, PD, IN Device type: Endpoint Class III Network Policy(Voice): VLAN 101, tagged, Layer-2 priority: 0, DSCP: 0 Network Policy(Voice Signal): VLAN 101, tagged, Layer-2 priority: 3, DSCP: 24 PD device, Power source: Unknown, Power Priority: Unknown, Wattage: 3.8 Location - not advertised
Total entries displayed: 1
If you cannot see any data collected verify the following:
Check the state of authentication session on the switch (it should be successful):
piborowi#show authentication sessions int g1/0/13 details
MAC Address: 20bb.c0de.06ae
IPv6 Address: Unknown
IPv4 Address: Unknown
Oper host mode: multi-domain
Oper control dir: both
Session timeout: N/A
Common Session ID: 0AE51820000002040099C216
Acct Session ID: 0x00000016
Current Policy: POLICY_Gi1/0/13
Service Template: DEFAULT_LINKSEC_POLICY_SHOULD_SECURE (priority 150)
Method status list:
mab Authc Success
Check if CDP and LLDP protocols are enabled. Check if there are any non-default commands regarding CDP/LLDP/etc. and how those can affect attribute retrieval from the endpoint
switch#sh running-config all | in cdp run
switch#sh running-config all | in lldp run
Verify in configuration guide for your endpoint if it supports CDP/LLDP/etc
If you do not see any data in this field or information is not complete verify 'device-sensor' commands, in particular filter-lists and filter-specs.
Step 3. Check if attributes are present in Radius Accounting
You can verify that using 'debug radius' command on the switch or performing packet capture between switch and ISE.
Mar 30 05:34:58.716: RADIUS(00000000): Send Accounting-Request to 126.96.36.199:1813 id 1646/85, len 378
Mar 30 05:34:58.716: RADIUS: authenticator 17 DA 12 8B 17 96 E2 0F - 5D 3D EC 79 3C ED 69 20
Mar 30 05:34:58.716: RADIUS: Vendor, Cisco  40
Mar 30 05:34:58.716: RADIUS: Cisco AVpair  34 "cdp-tlv= "
Mar 30 05:34:58.716: RADIUS: Vendor, Cisco  23
Mar 30 05:34:58.716: RADIUS: Cisco AVpair  17 "cdp-tlv= "
Mar 30 05:34:58.721: RADIUS: Vendor, Cisco  59
Mar 30 05:34:58.721: RADIUS: Cisco AVpair  53 "lldp-tlv= "
Mar 30 05:34:58.721: RADIUS: User-Name  19 "20-BB-C0-DE-06-AE"
Mar 30 05:34:58.721: RADIUS: Vendor, Cisco  49
Mar 30 05:34:58.721: RADIUS: Cisco AVpair  43 "audit-session-id=0AE518200000022800E2481C"
Mar 30 05:34:58.721: RADIUS: Vendor, Cisco  19
Mar 30 05:34:58.721: RADIUS: Cisco AVpair  13 "vlan-id=101"
Mar 30 05:34:58.721: RADIUS: Vendor, Cisco  18
Mar 30 05:34:58.721: RADIUS: Cisco AVpair  12 "method=mab"
Mar 30 05:34:58.721: RADIUS: Called-Station-Id  19 "F0-29-29-49-67-0D"
Mar 30 05:34:58.721: RADIUS: Calling-Station-Id  19 "20-BB-C0-DE-06-AE"
Mar 30 05:34:58.721: RADIUS: NAS-IP-Address  6 10.229.20.43
Mar 30 05:34:58.721: RADIUS: NAS-Port  6 60000
Mar 30 05:34:58.721: RADIUS: NAS-Port-Id  23 "GigabitEthernet1/0/13"
Mar 30 05:34:58.721: RADIUS: NAS-Port-Type  6 Ethernet 
Mar 30 05:34:58.721: RADIUS: Acct-Session-Id  10 "00000018"
Mar 30 05:34:58.721: RADIUS: Acct-Status-Type  6 Watchdog 
Mar 30 05:34:58.721: RADIUS: Event-Timestamp  6 1301463298
Mar 30 05:34:58.721: RADIUS: Acct-Input-Octets  6 538044
Mar 30 05:34:58.721: RADIUS: Acct-Output-Octets  6 3201914
Mar 30 05:34:58.721: RADIUS: Acct-Input-Packets  6 1686
Mar 30 05:34:58.721: RADIUS: Acct-Output-Packets  6 35354
Mar 30 05:34:58.721: RADIUS: Acct-Delay-Time  6 0
Mar 30 05:34:58.721: RADIUS(00000000): Sending a IPv4 Radius Packet
Mar 30 05:34:58.721: RADIUS(00000000): Started 5 sec timeout
Mar 30 05:34:58.737: RADIUS: Received from id 1646/85 10.62.145.51:1813, Accounting-response, len 20
Step 4. Verify profiler debugs on ISE
If the attributes were sent from the switch, it is possible to check if they were received on ISE. In order to check this, please enable profiler debugs for correct PSN node (Administration>System>Logging>Debug Log Configuration>PSN>profiler>debug) and perform authentication of the endpoint one more time.
Look for following information:
Debug indicating that radius probe received attributes:
A forwarder stores endpoints into the Cisco ISE database along with their attributes data, and then notifies the analyzer of new endpoints detected on your network. The analyzer classifies endpoints to the endpoint identity groups and stores endpoints with the matched profiles in the database.
Step 5. Typically after new attributes are added to the existing collection for specific device, this device/endpoint is added to profiling queue in order to check if it has to be assigned different profile based on new attributes: