22-2
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 22 Configuring Layer 3 Interfaces
Layer 3 Interface Configuration Guidelines and Restrictions
Layer 3 Interface Configuration Guidelines and Restrictions
When configuring Layer 3 interfaces, follow these guidelines and restrictions:
•
We recommend that you configure no more than 2,000 Layer 3 VLAN interfaces.
•
Release 12.2(18)SXE and later releases supports the
ip unnumbered
command on Layer 3 VLAN
interfaces.
•
Release 12.2(18)SXE and later releases supports the [
no
]
ip dhcp route
[
connected
|
static
]
command.
•
To support VLAN interfaces, create and configure VLANs and assign VLAN membership to
Layer 2 LAN ports. For more information, see
Chapter 14, “Configuring VLANs”
and
Chapter 13,
“Configuring VTP.”
•
Cisco 7600 series routers do not support:
–
Integrated routing and bridging (IRB)
–
Concurrent routing and bridging (CRB)
–
Remote source-route bridging (RSRB)
•
Use bridge groups on VLAN interfaces, sometimes called fall-back bridging, to bridge nonrouted
protocols. Bridge groups on VLAN interfaces are supported in software on the MSFC.
•
Cisco 7600 series routers do not support the IEEE bridging protocol for bridge groups. Configure
bridge groups to use the VLAN-bridge or the DEC spanning-tree protocol.
Configuring Subinterfaces on Layer 3 Interfaces
When configuring Layer 3 subinterfaces, follow these guidelines and restrictions:
•
With a PFC3, Release 12.2(18)SXE and later releases support these features on LAN port
subinterfaces:
–
IPv4 unicast forwarding, including MPLS VPN
–
IPv4 multicast forwarding, including MPLS VPN
–
6PE
–
EoMPLS
–
IPv4 unnumbered
–
Counters for subinterfaces in MIBS and with the
show vlans
command
–
iBGP and eBGP
–
OSPF
–
EIGRP
–
RIPv1/v2
–
RIPv2
–
ISIS
–
Static routing
–
Unidirectional link routing (UDLR)
–
IGMPv1, IGMPv2, IGMPv3