04-11-2013 04:37 PM - edited 03-07-2019 12:46 PM
Hi everyone
Is it considered bad practice to configure both a parent interface and its subinterfaces for IP forwarding? I'm talking about back to back routers here, no switches in between.
An example:
interface GigabitEthernet0/0/0
description Parent Interface - GRT
ip address 10.1.1.2 255.255.255.254
ip ospf message-digest-key 1 md5 7 <removed>
ip ospf network point-to-point
ip ospf 1 area 0
negotiation auto
cdp enable
!
interface GigabitEthernet0/0/0.900
description Subinterface - Client VRF
encapsulation dot1Q 900
vrf forwarding Client_VPN
ip address 10.0.252.4 255.255.255.254
ip pim sparse-mode
ip ospf message-digest-key 1 md5 7 <removed>
ip ospf network point-to-point
ip ospf 1 area 0
Or should you always keep the parent interface 'bare' and configure all IP forwarding on subinterfaces?
Thanks
Rich.
Solved! Go to Solution.
04-12-2013 08:30 AM
Hi Rich,
Either way, it will work fine. I just like to keep them all the same since the sub-interfaces will have vlan tags associated with them and the main interfaces does not.
HTH
04-11-2013 04:51 PM
Hi,
If you know, you don't need sub-interfaces, then just configure everything on the main interface. No need for extra config and space taken by the sub-interface when you do "sh run". This way, your config lines are shorter and simple.
HTH
04-12-2013 03:14 AM
Hi Reza
Thanks for your response.
I need multiple connections between the two routers (it's VRF-Lite), so I definitely need subinterfaces, but my question is, should all the connections use subinterfaces or is it okay to use the parent interface too?
My thinking is to run the GRT over the parent interface to kinda keep it separate from a human inspection point of view. That way, everyone knows the GRT runs on the parent interface in all situations. Technically I'm pretty sure it'll work fine, but I guess I'm asking more of a style/best practice question here. Or if there are any gotchas I haven't thought about. Do you see what I mean?
Thanks
Rich.
04-12-2013 08:30 AM
Hi Rich,
Either way, it will work fine. I just like to keep them all the same since the sub-interfaces will have vlan tags associated with them and the main interfaces does not.
HTH
04-12-2013 01:46 PM
Okay, thanks for your help Reza.
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