[dev] Issues with EVPN Type-5 Routes

Mohan Singamsetty msingamsetty at vmware.com
Fri Aug 10 18:55:29 EDT 2018


Hi all,

I have simple two node setup with below configuration on each node. I am trying to verify functionality related to EVPN Type-5 routes and observing few issues as listed below.

                                Node A ------------------ Node B

Most of the configuration is from

source: https://docs.cumulusnetworks.com/display/DOCS/Ethernet+Virtual+Private+Network+-+EVPN

Node A
router bgp 65000
bgp router-id 203.0.113.1
no bgp default ipv4-unicast
neighbor fabric peer-group
neighbor fabric remote-as 65001
neighbor fabric capability extended-nexthop
neighbor 203.0.113.2 peer-group fabric
!
address-family ipv4 unicast
  network 44.44.44.0/24
exit-address-family
!
address-family l2vpn evpn
  neighbor fabric activate
  advertise-all-vni
  advertise ipv4 unicast
exit-address-family
!
router bgp 65000 vrf Sri
bgp router-id 203.0.113.1
!
address-family ipv4 unicast
  network 45.45.45.0/24
exit-address-family
!
address-family l2vpn evpn
  advertise-all-vni
  advertise ipv4 unicast
exit-address-family
!
line vty
!

Node B
router bgp 65001
bgp router-id 203.0.113.2
no bgp default ipv4-unicast
neighbor fabric peer-group
neighbor fabric remote-as 65000
neighbor fabric capability extended-nexthop
neighbor 203.0.113.1 peer-group fabric
!
address-family ipv4 unicast
  network 54.54.54.0/24
exit-address-family
!
address-family l2vpn evpn
  neighbor fabric activate
  advertise-all-vni
  advertise ipv4 unicast
exit-address-family
!
router bgp 65001 vrf Sri
bgp router-id 203.0.113.2
!
address-family ipv4 unicast
  network 55.55.55.0/24
exit-address-family
!
address-family l2vpn evpn
  advertise-all-vni
  advertise ipv4 unicast
exit-address-family
!
line vty
!


  *   When I had this configuration in frr.conf and rebooted both the nodes, no Type-5 routes were advertised and the only routes I see are Type-3 and Type-2 routes and the output is as below.

Node_A# show bgp evpn route

BGP table version is 2, local router ID is 203.0.113.1

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

EVPN type-2 prefix: [2]:[EthTag]:[MAClen]:[MAC]:[IPlen]:[IP]

EVPN type-3 prefix: [3]:[EthTag]:[IPlen]:[OrigIP]

EVPN type-4 prefix: [4]:[ESI]:[IPlen]:[OrigIP]

EVPN type-5 prefix: [5]:[EthTag]:[IPlen]:[IP]



   Network          Next Hop            Metric LocPrf Weight Path

Route Distinguisher: 203.0.113.1:3

*> [2]:[0]:[48]:[00:50:56:b5:b4:53]

                    203.0.113.1                        32768 i

*> [3]:[0]:[32]:[203.0.113.1]

                    203.0.113.1                        32768 i

Route Distinguisher: 203.0.113.1:4

*> [3]:[0]:[32]:[203.0.113.1]

                    203.0.113.1                        32768 i

Route Distinguisher: 203.0.113.2:3

*> [3]:[0]:[32]:[203.0.113.2]

                    203.0.113.2                            0 65001 i

Route Distinguisher: 203.0.113.2:4

*> [3]:[0]:[32]:[203.0.113.2]

                    203.0.113.2                            0 65001 i



Displayed 5 prefixes (5 paths)

dev#

              I remember about an issue that was discussed by Donald and others earlier, where VRF configuration sequence does matter for Type-5 Routes. The mail thread that talks about this issue is @
https://lists.frrouting.org/pipermail/frog/2018-July/000205.html



  *   So I removed the bgp configuration from both the nodes as below
Node_A# conf t
Node_A (config)# no router bgp 65000
Node_A (config)# no router bgp 65000 vrf Sri
Node_A (config)#

Node_B# conf t
Node_B (config)# no router bgp 65001
Node_B (config)# no router bgp 65001 vrf Sri
Node_B (config)#


  *   Configured bgp and associated VRF again on the two nodes (vrf Sri configuration was not removed so honoring the sequence requirements from the above thread). After this the bgp evpn routes on each node are as below.

Node A

Node_A# show bgp evpn route

BGP table version is 1, local router ID is 203.0.113.1

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

EVPN type-2 prefix: [2]:[EthTag]:[MAClen]:[MAC]:[IPlen]:[IP]

EVPN type-3 prefix: [3]:[EthTag]:[IPlen]:[OrigIP]

EVPN type-4 prefix: [4]:[ESI]:[IPlen]:[OrigIP]

EVPN type-5 prefix: [5]:[EthTag]:[IPlen]:[IP]



   Network          Next Hop            Metric LocPrf Weight Path

Route Distinguisher: 203.0.113.1:5

*> [5]:[0]:[24]:[45.45.45.0]

                    0.0.0.0                  0         32768 i



Displayed 1 prefixes (1 paths)



Node B

Node_B# show bgp evpn route

BGP table version is 1, local router ID is 203.0.113.2

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

EVPN type-2 prefix: [2]:[EthTag]:[MAClen]:[MAC]:[IPlen]:[IP]

EVPN type-3 prefix: [3]:[EthTag]:[IPlen]:[OrigIP]

EVPN type-4 prefix: [4]:[ESI]:[IPlen]:[OrigIP]

EVPN type-5 prefix: [5]:[EthTag]:[IPlen]:[IP]



   Network          Next Hop            Metric LocPrf Weight Path

Route Distinguisher: 203.0.113.1:5

*> [5]:[0]:[24]:[45.45.45.0]

                    203.0.113.1              0             0 65000 i



Displayed 1 prefixes (1 paths)

EdgeRouter-2#


Some of the observations:

  1.  When the two nodes were brought for the first time, no Type-5 routes were advertised initially. Only Type-3 and Type-2.
  2.  Once I unconfigure BGP and configure again, neither Type-3 nor Type-2 routes were showing up.
  3.  After this, It looks like Node-A is advertising Type-5 route for one of the prefix that was added through network command and this indeed received by Node-B. But this is not happening from Node B to Node A.
  4.  IP-Prefix from VRF Sri was advertised by Node A, but this is not happening for the IP-Prefix that was available at global level.

I am trying to understand the reason for above behavior. Can you help me to identify if I am missing anything in configuration ? If not what am I missing here ? Unfortunately, not many log messages were available in this part of the code and I am trying to add more and debug, but any quick help on this would be really useful.

This is latest FRR (may be a month old). I do have the log files for both the nodes with all necessary BGP debugs enabled.

Let me know if you need any more details on this.

Thanks,
Mohan




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