Cisco 7604

22-3
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 22 Configuring Layer 3 Interfaces
Configuring Subinterfaces on Layer 3 Interfaces
– PIMv1, PIMv2
– SSM IGMPv3lite and URD
– Stub IP multicast routing
– IGMP join
– IGMP static group
– Multicast routing monitor (MRM)
– Multicast source discovery protocol (MSDP)
– SSM
– IPv4 Ping
– IPv6 Ping
• These restrictions apply to releases earlier than Release 12.2(18)SXE:
– Configure subinterfaces only to support MPLS.
– Do not configure ISL encapsulation.
• Always use the native keyword when the VLAN ID is the ID of the IEEE 802.1Q native VLAN. Do
not configure encapsulation on the native VLAN of an IEEE 802.1Q trunk without the native
keyword.
• Because VLAN IDs are global to the router, you can use a VLAN internally, on a subinterface, or
with a Layer 3 VLAN interface.
– You cannot configure an internal VLAN on a subinterface or a Layer 3 VLAN interface.
– You cannot configure a subinterface VLAN on a Layer 3 VLAN interface.
– You cannot configure a VLAN used with a Layer 3 VLAN interface on a subinterface.
Note You cannot configure a VLAN used on one interface or subinterface on another interface or
subinterface.
• You can configure subinterfaces with any normal range or extended range VLAN ID in VTP
transparent mode. Because VLAN IDs 1 to 1005 are global in the VTP domain and can be defined
on other network devices in the VTP domain, you can use only extended range VLANs with
subinterfaces in VTP client or server mode. In VTP client or server mode, normal range VLANs are
excluded from subinterfaces.
Note If you configure normal range VLANs on subinterfaces, you cannot change the VTP mode
from transparent.
To configure a subinterface, perform this task:
Command Purpose
Step 1
Router> enable
Enters privileged EXEC mode.
Step 2
Router# configure terminal
Enters global configuration mode.
Step 3
Router(config)# interface
{{
type
1
slot / port . subinterface } | {port-channel
port_channel_number . subinterface }}
Selects an interface and enters subinterface configuration
mode.