Advertise the static routes configured on L3Out-to-RTR via BGP to L3Out-to-CoreSwitch

[raza555]

Hi,

On ACI we have configured two L3Out using BGP as below;

1) L3Out-to-RTR

2) L3Out-to-CoreSwitch

I have configured some static routes on L3Out-to-RTR as below;
External Routed Networks->L3Out-to-RTR->Logical Node Profile->Configured Nodes->Node-101 (Static Routes are added here)

Please advise that how I can advertise these static routes via BGP to the CoreSwitch

At the moment, when I run on the Leaf 'show ip route vrf common:xxx' I can see these as static routes, but they are not visible on Leaf ' show ip route bgp vrf common:xxx'

Question: How I can advertise the static routes configured on L3Out-to-RTR to the BGP, so I can see them on LEAF101 BGP table and CoreSwitch BGP table

I have drawn a quick diagram to explain the requirement, hope it helps.

Thanks,

[ecsnnsls · Accepted solution]

Hi @raza555 ,

On the L3Out-to-RTR, add subnet 20.20.20.0/24 under the External EPG and select "External subnets for External EPG"
Now, on the L3Out-to-CoreSwitch add this subnet 20.20.20.0/24 with the "export route control" checked. This will advertise the 20.20.20.0/24 subnet out through the L3Out-to-CoreSwitch.

Make sure you have configured the spines as MP-BGP route reflectors. This is required when you want external routes to be advertised within the fabric. You can follow this link to configure the RRs.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/2-x/L3_config/b_Cisco_APIC_Layer_3_Configuration_Guide/b_Cisco_APIC_Layer_3_Configuration_Guide_chapter_01001.html#task_9A21E0FBB724446991B63D44243A6E92

[raza555 · Accepted solution]

Hi,

Thanks for suggesting the solution.

Just for clarity, please find below routings from the ACI.

Please confirm that below solution is good or I need something else to advertise LEAF-01 Static route to CoreSwitch?

ACI CURRENT ROUTING:

LEAF-01 is configured with L3Out-to-RTR
LEAF-04 is configured with L3Out-to-CoreSwitch

LEAF-01# show ip route vrf common:ABC 20.20.20.0/24
IP Route Table for VRF "common:ABC"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

20.20.20.0/24, ubest/mbest: 1/0
*via 10.10.10.1, vlan600, [1/0], 01w06d, static

LEAF-04# show ip route vrf common:ABC 20.20.20.0/24
IP Route Table for VRF "common:ABC"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

20.20.20.0/24, ubest/mbest: 2/0
*via 172.30.30.10%overlay-1, [1/0], 02w06d, bgp-65500, internal, tag 65501
recursive next hop: 172.30.30.10/32%overlay-1
*via 172.30.30.11%overlay-1, [1/0], 02w06d, bgp-65500, internal, tag 65501
recursive next hop: 172.30.30.11/32%overlay-1

By looking at the above routing for clarity; Please suggest shall I just configure 'L3Out-to-CoreSwitch' as follows

SOLUTION:
1) L3Out-to-CoreSwitch
Network->EPG-L3Out-to-CoreSwitch
Subnets:
20.20.20.0/24 Export Route Control Subnet

2) L3Out-to-CoreSwitch
Route map for import and export route control
ACI-TO-CoreSwitch
Match Prefix: (ADD BELOW SUBNET)
20.20.20.0/24

By looking at the routings or LEAF-01 & LEAF-04, Do I need to do to anything under L3Out-to-RTR?

Thanks,

[ecsnnsls]

Hi @raza555,

Looks good, route map is not absolutely required though.

[raza555]

Hi @ecsnnsls 

Thanks alot for great help.

Cheer,