Virtual Router Redundancy Protocol (VRRP) Fabric Routing
Virtual Router Redundancy Protocol (VRRP) has one master router that does L3
routing and one or more backup routers that perform L2 forwarding of packets toward the master
router, as per VRRP RFC specification. With this method, L3 routing capability of backup router
goes unused. This also causes loss of bandwidth in the links that connect master and backup
routers. This issue is present in any topology where host traffic is flowing using the backup
routers. With multiple backup routers, traffic from hosts attached to some backup routers have to
traverse multiple links to reach the master router. This causes loss of bandwidth in multiple
links toward the master.
This feature allows backup routers to take part in L3 routing for the
packets it receives with the destination address equal to VMAC. Backup routers enabled with this
feature are called Fabric Routing Enabled Backup (FREB) routers. This feature allows
- Load sharing of traffic between VRRP routers
- Saves bandwidth on the links connecting master and backup routers
This solution is applicable for all topologies, such as MLAG, EAPS, or STP.
Platform
Summit X450-G2, X460-G2, X670-G2, X770, and ExtremeSwitching X620, X440-G2
series switches
Limitations
- Fabric Routing feature will not be supported for VRRP VR for which Virtual IP is same as
interface IP (owned IP).
- Traffic sent from host destined for VIP, will be L3 forwarded by FREB router if FREB router
sits in between, even though both are in same subnet. VIP cannot be used to run protocols
between host and VRRP router which will expect TTL value not be decremented, for example
BFD.
- PVLAN configuration is not supported in this release.
- VLAN Aggregation configuration is not supported in this release.
New CLI Commands
configure vrrp {vlan
vlan_name
vr
vr_id | all} fabric-route-mode [on | off]