This topic describes subinterfaces on the Cisco 8000 Series Router, which are logical interfaces created on a hardware interface to segregate traffic into separate logical channels and better utilize the available bandwidth.
Subinterfaces, created on a hardware interface, are logical interfaces that
-
allows the segregation of traffic into separate logical channels on a single hardware interface, and
-
allows for the better utilization of the available bandwidth on the physical interface.
You can distinguish subinterfaces from each other by adding an extension at the end of the interface name and designation. For instance, the system indicates Ethernet subinterface 23 on the physical interface designated TenGigE 0/1/0/0, by TenGigE 0/1/0/0.23.
Before the system allows a subinterface to pass traffic, it must have a valid tagging protocol encapsulation and VLAN identifier assigned. All Ethernet subinterfaces always default to the 802.1Q VLAN encapsulation. However, you must explicitly define the VLAN identifier.
Supported encapsulation
Interface Type |
Encapsulation |
Standard |
Support Status |
|---|---|---|---|
| Layer 3 interface Layer 3 subinterface Layer 3 bundle subinterface |
Single-Tag Encapsulation |
dot1ad |
Supported (From Cisco IOS XR Software Release 24.4.1 onwards) |
dot1q |
Supported. |
||
Double-Tag Encapsulation |
dot1ad <> dot1q<> |
Supported. |
|
dot1q <> dot1q<> |
1Supported. |
For information about supported encapsulation for Layer 2 interfaces and subinterfaces, see Virtual LANs in Layer 2 VPNs.