L3VPN/MBGP. Same IP in VRF

[AndreyBaycharov]

Hi!
There is a problem when using the same IP addresses in VRF. L3VPN works fine if the loopback interfaces in global vrf and client (vrf test) have different ip addresses. In the packets, I see two MPLS labels, transport and service. Scheme 1.

Scheme 1.pdf

R1# sh ip bgp ipv4 vpn
BGP table version is 13, local router ID is 1.1.1.1, vrf id 0
Default local pref 100, local AS 64500
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 64500:100
*>i11.11.11.11/32 3.3.3.3 0 100 0 ?
UN=3.3.3.3 label=21 type=bgp, subtype=0
*> 22.22.22.22/32 0.0.0.0@11< 0 32768 ?
UN=0.0.0.0 EC{64500:100} label=80 type=bgp, subtype=5
*>i192.168.20.0/24 3.3.3.3 0 100 0 ?
UN=3.3.3.3 label=20 type=bgp, subtype=0

R03#sh ip bgp vpnv4 vrf test
BGP table version is 16, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 64500:100 (default for vrf test)
*> 11.11.11.11/32 0.0.0.0 0 32768 ?
*>i22.22.22.22/32 1.1.1.1 0 100 0 ?
*> 192.168.20.0 0.0.0.0 0 32768 ?

PROBLEM:
If I use the same addresses on loopback vrf global and loopback vrf test (client vrf) on R01, L3VPN doesn't work correctly. Only the transport label is present in the sent packets. Scheme 2.

scheme 2.pdf

R1(config-if)# R1#
R1# sh ip bgp ipv4 vpn
BGP table version is 15, local router ID is 1.1.1.1, vrf id 0
Default local pref 100, local AS 64500
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 64500:100
*> 1.1.1.1/32 0.0.0.0@11< 0 32768 ?
UN=0.0.0.0 EC{64500:100} label=80 type=bgp, subtype=5
*>i3.3.3.3/32 3.3.3.3 0 100 0 ?
UN=3.3.3.3 label=19 type=bgp, subtype=0
*>i11.11.11.11/32 3.3.3.3 0 100 0 ?
UN=3.3.3.3 label=21 type=bgp, subtype=0
*> 22.22.22.22/32 0.0.0.0@11< 0 32768 ?
UN=0.0.0.0 EC{64500:100} label=80 type=bgp, subtype=5
*>i192.168.20.0/24 3.3.3.3 0 100 0 ?
UN=3.3.3.3 label=20 type=bgp, subtype=0

Displayed 5 routes and 5 total paths

R03#sh ip bgp vpnv4 vrf test
BGP table version is 19, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 64500:100 (default for vrf test)
*>i1.1.1.1/32 1.1.1.1 0 100 0 ?
*> 3.3.3.3/32 0.0.0.0 0 32768 ?
*> 11.11.11.11/32 0.0.0.0 0 32768 ?
*>i22.22.22.22/32 1.1.1.1 0 100 0 ?
*> 192.168.20.0 0.0.0.0 0 32768 ?

Based on traffic dumps, I see incorrect packets from FRR , only the transport label is transmitted

label from cisco is correct - transport label and service label

[AndreyBaycharov]

This is correct screenshot icmp packet from cisco.

Package from cisco has 2 labels

[AndreyBaycharov]

LDP works as it should.
Found the reason, there is no route in 3.3.3.3/32 in vrf "test" table. I get a route to R01 via iBGP, but it doesn't get into the vrfs routing table.

I think that this is due to the fact that this route is in the global table

I still do not understand how to solve the problem with the route, maybe someone faced a similar problem?