I just want to know if it's possible to implement mLACP (with VSS) or vPC on L3 interfaces. I just can't find any answer to this on cisco doc.
Thanks,
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1You can have layer-3 port channels. A link failure in a layer-3 port channel fails over much faster than even a routing protocol. – Ron Maupin♦ Jan 2 '17 at 16:02
(m)LACP and vPC are Layer 2 technologies, thus they don't apply to layer 3 interfaces
At layer 3 you use for example VRRP (to provide gateway to hosts) or routing protocols (like OSPF) to achieve redundancy and automatic switchover.
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Newer NXOS versions on 7K and 9K definitely support L3 VPC's now (i.e. running a routing protocol over SVI's carried over VPC links). The typical use-case is running a dynamic routing protocol to a firewall but it can be used in most topologies. – rnxrx Jan 3 '17 at 0:36
Yes, you can absolutely. You can setup a Port-Channel interface and set it with an IP. This is referred to as a Layer 3 port-channel and you can run routing protocols over it as needed. This will work regardless of if you are running this directly on the same switch or over a mLACP/ vPC.
int po1
description Uplink
ip address 10.0.1.1 255.255.255.0
no switchport
int gi1/1/2
no switchport (--- important that all interfaces are in layer 3
channel-group 1 mode active
int eth2/1/2
no switchport (--- important that all interfaces are in layer 3
channel-group 1 mode active
This would be a very bare bones example.
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This is true on the downstream switch and in the case of VSS on a pair of C6K's but is not necessarily true on platforms supporting VPC (NXOS boxes - 7K, 5K, 9K, etc). Some support this functionality in recent code versions but require additional explicit configuration while others don't support it at all. There are also a bunch of caveats in terms of which protocols are supported as well as questions of protocol configuration, behavior of multicast, etc. – rnxrx Jan 3 '17 at 0:38
