VE route-only mode
By default, physical ports and port-channels (LAG ports) support both Layer 2 switching and Layer 3 routing. VE route-only mode enables these ports to act exclusively as a Layer 3 virtual Ethernet (VE) interface, dropping all ingress packets that require Layer 2 switching.
The MAC learning of dropped packets is not affected by this feature. ARP requests (broadcast), LACP, and BPDU packet processing are also not affected. The following table lists the effects of this mode on a variety of features.
Table 1. Effects of VE route-only mode on features
| Feature
|
Ingress port as route-only port (incoming frames)
|
Egress port as route-only port (outgoing frames)
|
| Packets requiring switching
|
Drop, learn MAC address
|
Forwarded/switched
|
| Packets requiring routing
|
Forwarded
|
Forwarded
|
| ARP requests
|
Trapped/punted, ARP response generated
|
Forwarded
|
| LACP packets
|
Trapped/punted and processed
|
Forwarded
|
| STP/BPDU packets
|
Trapped/punted and processed
|
Forwarded
|
Note the following considerations and limitations:
- Egress packets through a port configured as route-only are transmitted irrespective of whether they are switched or routed.
- This feature is enabled on the active management module (MM), and is available on the other MM after a failover.
- The number of TCAM entries required for this feature depends on the maximum number of physical ports. On a there are approximately 40 physical ports per PPE , and a maximum of 512 LAG ports for the entire system. Therefore the maximum number of TCAM entries for route-only support is 40. These entries are available on all TCAM profiles.
