Sharing an Equivalence Class Entry Across Multiple VRFs
This enables the sharing of the same Forwarding Equivalence Class (FEC) entry across multiple VRF’s and achieves higher scale in VPN deployments by making optimal use of hardware resources. The VPN path routes are imported to multiple VRF for MPLS VPN address family in BGP, individual FEC entry in the hardware table is used for each VRF.
The following configuration in router BGP mode at BGP instance level allows sharing FEC, when the VPN path is imported to multiple VRFs.
bgp fec skip in-place update
The following configures disable FEC and restores default configuration.
[no| default] bgp fec skip in-place update
Note: Changing the configuration in a production system may increase FEC
usage.
The following example displays BGP VPN-IPv4 routes for prefix
20.0.1.0/24, which is imported to
four
VRFs.
switch# show bgp vpn-ipv4 20.0.1.0/24 detail
BGP routing table information for VRF default
Router identifier 0.0.0.1, local AS number 300
BGP routing table entry for IPv4 prefix 20.0.1.0/24, Route Distinguisher: 11.0.1.1:0
Paths: 1 available
301
11.0.1.1 from 10.0.0.2 (0.0.1.1)
Origin IGP, metric -, localpref 100, weight 0, valid, external, best
Extended Community: Route-Target-AS:300:0 Route-Target-AS:301:0
MPLS label: 116507This route was using four FEC entries for each VRF before the
change.
switch# show platform jericho ip route 20.0.1.0/24
Tunnel Type: M(mpls), G(gre), MoG(mpls-over-gre),
VXLAN-o(VXLAN outer-rewrite info), VXLAN-i(VXLAN inner-rewrite info)
* - Routes in LEM
D - ECMP is divergent across switching chips
---------------------------------------------------------------------------------------------------------
| Routing Table | |
|---------------------------------------------------------------------------------------------------------
|VRF| Destination | | | | | | ECMP| FEC | Tunnel
| ID| Subnet | Cmd | Destination | VID |Outlif | MAC / CPU Code |Index| Index|T Value
---------------------------------------------------------------------------------------------------------
|1 |20.0.1.0/24 |ROUTE| FEC 32776 |0 | - | | - |49152 |M 116507
|2 |20.0.1.0/24 |ROUTE| FEC 32776 |0 | - | | - |49154 |M 116507
|3 |20.0.1.0/24 |ROUTE| FEC 32776 |0 | - | | - |49155 |M 116507
|4 |20.0.1.0/24 |ROUTE| FEC 32776 |0 | - | | - |49156 |M 116507 The following uses single FEC entry For VPN routes imported to all
VRFs after configuring bgp fec skip in-place update event
all
command.
switch# show platform jericho ip route 20.0.1.0/24
Tunnel Type: M(mpls), G(gre), MoG(mpls-over-gre),
VXLAN-o(VXLAN outer-rewrite info), VXLAN-i(VXLAN inner-rewrite info)
* - Routes in LEM
D - ECMP is divergent across switching chips
---------------------------------------------------------------------------------------------------------
| Routing Table | |
|---------------------------------------------------------------------------------------------------------
|VRF| Destination | | | | | | ECMP| FEC | Tunnel
| ID| Subnet | Cmd | Destination | VID |Outlif | MAC / CPU Code |Index| Index|T Value
---------------------------------------------------------------------------------------------------------
|1 |20.0.1.0/24 |ROUTE| FEC 32780 |0 | - | | - |49152 |M 116507
|2 |20.0.1.0/24 |ROUTE| FEC 32780 |0 | - | | - |49152 |M 116507
|3 |20.0.1.0/24 |ROUTE| FEC 32780 |0 | - | | - |49152 |M 116507
|4 |20.0.1.0/24 |ROUTE| FEC 32780 |0 | - | | - |49152 |M 116507