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Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Chapter       Configuring Security Features
SGT over Ethernet Tagging
SGT over Ethernet Tagging 
Cisco TrustSec (CTS) is an end-to-end network infrastructure that provides a scalable architecture for 
enforcement of role-based access control, identity-aware networking, and data confidentiality that helps 
to secure the network and its resources. CTS works by identifying and authenticating each network user 
and resource and assigning a 16-bit number called Security Group Tag (SGT). SGT is then propagated 
between network hops to allow intermediary devices (switches and routers) to enforce policies based on 
the identity tag.
CTS-capable devices have built-in hardware capabilities than can send and receive packets with SGT 
embedded in the MAC (L2) layer. This feature is called L2-SGT imposition. This allows Ethernet 
interfaces on the device to be enabled for L2-SGT imposition to enable the device to insert an SGT in 
the packet that is to be carried to its next- hop Ethernet neighbor. SGT over Ethernet Tagging is a type 
of hop-by-hop propagation of SGTs embedded in clear-text (unencrypted) Ethernet packets. 
Restrictions for SGT over Ethernet Tagging 
• SGT over Ethernet Tagging is supported on plain-text Ethernet frames only.
• SGT over Ethernet Tagging is supported on on-board Gigabit Ethernet interfaces on the following 
Cisco ISR G2 Series routers:
–
Cisco ISR G2 2951 
–
Cisco ISR G2 3945 
–
Cisco ISR G2 3900 E Series
–
Cisco ISR G2 1921 
–
ISR G2 1941 
–
ISR G2 2901 
–
ISR G2 2911 
–
ISR G2 2921 
Configuring SGT over Ethernet Tagging
Perform these steps to configure SGT over Ethernet Tagging.
SUMMARY STEPS
1. enable 
2. configure terminal 
3. interface gigabitethernet slot/port 
4. cts manual 
5. propagate sgt
6. policy static sgt tag [trusted] 
7. end