BGP listen range problem


Hello!

We're testing Cumulus Linux on Dell switches. I've got problem with BGP session using listen range on spine (it's not a Dell with Cumulus) and basic config on leaf:

Spine:
router bgp 64512
bgp listen range 172.16.0.96/28 peer-group abc remote-as 65002
neighbor abc peer-group
neighbor abc fall-over bfd
neighbor abc password xyz

Leaf:
router bgp 65002
bgp router-id 172.16.0.105
bgp log-neighbor-changes
neighbor abc peer-group
neighbor abc remote-as 64512
neighbor abc bfd
neighbor abc password xyz
neighbor 172.16.0.104 peer-group mFabric

sh ip bgp summary
BGP router identifier 172.16.0.105, local AS number 65002
BGP table version 0
RIB entries 0, using 0 bytes of memory
Peers 1, using 17 KiB of memory
Peer groups 1, using 56 bytes of memory

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.104 4 64512 0 0 0 0 0 never Active

ping 172.16.0.104PING 172.16.0.104 (172.16.0.104) 56(84) bytes of data.
64 bytes from 172.16.0.104: icmp_req=1 ttl=64 time=0.402 ms
64 bytes from 172.16.0.104: icmp_req=2 ttl=64 time=0.346 ms
64 bytes from 172.16.0.104: icmp_req=3 ttl=64 time=0.349 ms

When I configure Spine without listen range (neighbor 172.16.0.105 remote-as 65002), BGP session works fine. Can You give me any advice? Thank You.

BTW We're using CumulusLinux 2.4 (made upgrade yesterday)

8 replies

Hi Grzegorz,
For the Leaf, is that the full bgp config? I ask because 172.16.0.104 is configured to be a member of the mFabric peer-group but I do not see where the peer-group is defined (I see 'abc' instead). That would prevent Leaf from trying to actively open a session to the Spine.

Daniel

Hello,
I've made typo when I was pasting config. Peer-group is abc in this case.
On the spine there is "neighbor abc fall-over bfd" but there is no fall-over command in quagga in 2.5.4...that is an IOS BGP command. Did you grab the config from the wrong spine or are we troubleshooting listen range on IOS? 🙂 If the latter I would run tcpdump on the leaf to verify that it is attempting to open the BGP session.
Sorry I just noticed your "it's not a Dell with Cumulus" comment. ok so the spine is running IOS. Can you try the following:

- remove the "fall-over bfd" line from the spine and "neighbor abc bfd" from the leaf. I do not recall if IOS support BFD for dynamic peers....it is worth eliminating this variable.

- if that does not work also try removing the password, just to eliminate another variable

To be honest spine is running EOS 🙂

I made config without options that you've mentioned. So the spine:

SPINE1#sh running-config | i Cumulus
bgp listen range 172.16.0.96/28 peer-group Cumulus remote-as 65002
neighbor Cumulus peer-group
neighbor Cumulus maximum-routes 12000

SPINE1#ping 172.16.0.105
PING 172.16.0.105 (172.16.0.105) 72(100) bytes of data.
80 bytes from 172.16.0.105: icmp_req=1 ttl=64 time=0.443 ms
80 bytes from 172.16.0.105: icmp_req=2 ttl=64 time=0.286 ms
80 bytes from 172.16.0.105: icmp_req=3 ttl=64 time=0.257 ms
80 bytes from 172.16.0.105: icmp_req=4 ttl=64 time=0.255 ms
80 bytes from 172.16.0.105: icmp_req=5 ttl=64 time=0.247 ms

--- 172.16.0.105 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 1ms
rtt min/avg/max/mdev = 0.247/0.297/0.443/0.076 ms, ipg/ewma 0.367/0.367 ms

Leaf:

!router bgp 65002
bgp router-id 172.16.0.105
bgp log-neighbor-changes
neighbor Cumulus peer-group
neighbor Cumulus remote-as 64512
neighbor 172.16.0.104 peer-group Cumulus
!
ip forwarding
ipv6 forwarding
!
line vty
!
end
LEAF5-CL# ping 172.16.0.104
PING 172.16.0.104 (172.16.0.104) 56(84) bytes of data.
64 bytes from 172.16.0.104: icmp_req=1 ttl=64 time=2.56 ms
64 bytes from 172.16.0.104: icmp_req=2 ttl=64 time=0.383 ms
64 bytes from 172.16.0.104: icmp_req=3 ttl=64 time=0.331 ms
^C
--- 172.16.0.104 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2000ms
rtt min/avg/max/mdev = 0.331/1.094/2.568/1.042 ms
LEAF5-CL# sh ip bgp summary
BGP router identifier 172.16.0.105, local AS number 65002
BGP table version 0
RIB entries 0, using 0 bytes of memory
Peers 1, using 17 KiB of memory
Peer groups 1, using 56 bytes of memory

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.104 4 64512 0 0 0 0 0 never Active

Also our switches had crashes and I've got support files. Can I send it to support?

Regards,
Grzegorz

For the crashes yes please open a support case so we can take a look at those.

On the leaf can you run tcpdump on the interface used to connect to the spine to verify that we are attempting to open a BGP connection? Let us figure out if that is happening (it should be) and then plan our next steps.
Unfortunately right now, I don't have any possibility to open case. Maybe there is some way to fix it? 🙂
Userlevel 5
Grzegorz, At this point I would recommend you reach out to our Sales engineers at sales@cumulusnetworks.com , They can help you get setup so our support team can assist you more in depth and push this forward. Thanks!

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