Software Configuration Guide, Cisco IOS Release 15.2(2)E (Catalyst 2960, 2960-S, 2960-SF and 2960-Plus Switches)
Configuring Cisco TrustSec
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Configuring Cisco TrustSec

Configuring Cisco TrustSec

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http:/​/​www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for Cisco TrustSec

The following guidelines and limitations apply to configuring Cisco TrustSec SGT and SGACL:

  • You cannot statically map an IP-subnet to an SGT. You can only map IP addresses to an SGT. When you configure IP address-to-SGT mappings, the IP address prefix must be 32.

  • If a port is configured in Multi-Auth mode, all hosts connecting on that port must be assigned the same SGT. When a host tries to authenticate, its assigned SGT must be the same as the SGT assigned to a previously authenticated host. If a host tries to authenticate and its SGT is different from the SGT of a previously authenticated host, the VLAN port (VP) to which these hosts belong is error-disabled.

  • Cisco TrustSec enforcement is supported only on up to eight VLANs on a VLAN-trunk link. If there are more than eight VLANs configured on a VLAN-trunk link and Cisco TrustSec enforcement is enabled on those VLANs, the switch ports on those VLAN-trunk links will be error-disabled.

  • The switch can assign SGT and apply corresponding SGACL to end-hosts based on SXP listening only if the end-hosts are Layer2 adjacent to the switch.

  • Port-to-SGT mapping can be configured only on Cisco TrustSec links (that is, switch-to-switch links). Port-to-SGT mapping cannot be configured on host-to-switch links.

  • When port-to-SGT mapping is configured on a port, an SGT is assigned to all ingress traffic on that port. There is no SGACL enforcement for egress traffic on the port.

  • Cisco TrustSec uses AES-128 GCM and GMAC and is compliant with the 802.1AE standard. GCM is not supported on switches running the NPE or the LAN base image.

  • Cisco TrustSec NDAC SAP is supported on trunk ports because it is intended only for network device to network device links, that is, switch-to-switch links. It is not supported on:

    • Host facing access ports (these ports support MKA MACsec)
    • Switch virtual interfaces (SVIs)
    • SPAN destination ports
  • The switch also does not support security group ACLs.

Information about Cisco TrustSec

Cisco TrustSec provides security improvements to Cisco network devices based on the capability to strongly identify users, hosts, and network devices within a network. TrustSec provides topology-independent and scalable access controls by uniquely classifying data traffic for a particular role. TrustSec ensures data confidentiality and integrity by establishing trust among authenticated peers and encrypting links with those peers.

The key component of Cisco TrustSec is the Cisco Identity Services Engine (ISE). Cisco ISE can provision switches with TrustSec Identities and Security Group ACLs (SGACLs), though these may be configured manually on the switch.

Cisco TrustSec Features

The table below lists the TrustSec features to be eventually implemented on TrustSec-enabled Cisco switches. Successive general availability releases of TrustSec will expand the number of switches supported and the number of TrustSec features supported per switch.

Cisco TrustSec Feature Description
802.1AE Tagging (MACsec)

Protocol for IEEE 802.1AE-based wire-rate hop-to-hop Layer 2 encryption.

Between MACsec-capable devices, packets are encrypted on egress from the transmitting device, decrypted on ingress to the receiving device, and in the clear within the devices.

This feature is only available between TrustSec hardware-capable devices.

Endpoint Admission Control (EAC)

EAC is an authentication process for an endpoint user or a device connecting to the TrustSec domain. Usually EAC takes place at the access level switch. Successful authentication and authorization in the EAC process results in Security Group Tag assignment for the user or device. Currently EAC can be 802.1X, MAC Authentication Bypass (MAB), and Web Authentication Proxy (WebAuth).

Network Device Admission Control (NDAC)

NDAC is an authentication process where each network device in the TrustSec domain can verify the credentials and trustworthiness of its peer device. NDAC utilizes an authentication framework based on IEEE 802.1X port-based authentication and uses EAP-FAST as its EAP method. Successful authentication and authorization in NDAC process results in Security Association Protocol negotiation for IEEE 802.1AE encryption.

Security Group Access Control List (SGACL)

A Security Group Access Control List (SGACL) associates a Security Group Tag with a policy. The policy is enforced upon SGT-tagged traffic egressing the TrustSec domain.

Security Association Protocol (SAP)

After NDAC authentication, the Security Association Protocol (SAP) automatically negotiates keys and the cipher suite for subsequent MACSec link encryption between TrustSec peers. SAP is defined in IEEE 802.11i.

Security Group Tag (SGT)

An SGT is a 16-bit single label indicating the security classification of a source in the TrustSec domain. It is appended to an Ethernet frame or an IP packet.

SGT Exchange Protocol (SXP)

Security Group Tag Exchange Protocol (SXP). With SXP, devices that are not TrustSec-hardware-capable can receive SGT attributes for authenticated users and devices from the Cisco Identity Services Engine (ISE) or the Cisco Secure Access Control System (ACS). The devices can then forward a sourceIP-to-SGT binding to a TrustSec-hardware-capable device will tag the source traffic for SGACL enforcement.

When both ends of a link support 802.1AE MACsec, SAP negotiation occurs. An EAPOL-key exchange occurs between the supplicant and the authenticator to negotiate a cipher suite, exchange security parameters, and manage keys. Successful completion of these tasks results in the establishment of a security association (SA).

Depending on your software version and licensing and link hardware support, SAP negotiation can use one of these modes of operation:
  • Galois Counter Mode (GCM)—authentication and encryption
  • GCM authentication (GMAC)— GCM authentication, no encryption
  • No Encapsulation—no encapsulation (clear text)
  • Null—encapsulation, no authentication or encryption

Additional References

Related Documents

Related Topic Document Title
Various TrustSec Featurette configurations and examples

Cisco TrustSec Configuration Guide, Cisco IOS Release 15SY

http:/​/​www.cisco.com/​en/​US/​docs/​ios-xml/​ios/​sec_usr_cts/​configuration/​15-sy/​sec-cts-15-sy-book.html

Cisco TrustSec Configuration Guide, Cisco IOS XE Release 3S

http:/​/​www.cisco.com/​en/​US/​docs/​ios-xml/​ios/​sec_usr_cts/​configuration/​xe-3s/​cts-sgt-handling-imp-fwd.html

To configure Cisco Trustsec on the switch

See the Cisco TrustSec Switch Configuration Guide at the following URL:

http:/​/​www.cisco.com/​en/​US/​docs/​switches/​lan/​trustsec/​configuration/​guide/​trustsec.html

Release notes for Cisco TrustSec

http:/​/​www.cisco.com/​en/​US/​docs/​switches/​lan/​trustsec/​release/​notes/​rn_​cts_​crossplat.html

Additional information about the Cisco TrustSec solution, including overviews, datasheets, features by platform matrix, and case studies

http:/​/​www.cisco.com/​en/​US/​netsol/​ns1051/​index.html

Error Message Decoder

Description Link

To help you research and resolve system error messages in this release, use the Error Message Decoder tool.

https:/​/​www.cisco.com/​cgi-bin/​Support/​Errordecoder/​index.cgi

MIBs

MIB MIBs Link
CISCO-TRUSTSEC-POLICY-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http:/​/​www.cisco.com/​go/​mibs

Technical Assistance

Description Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http:/​/​www.cisco.com/​support