Troubleshooting BGP
Use the following commands to troubleshoot BGP.
Basic Troubleshooting Commands
Run the following commands to help you troubleshoot BGP.
Show BGP configuration Summary
To show a summary of the BGP configuration on the switch, run the NVUE nv show router bgp command or the vtysh show ip bgp summary command. For example:
cumulus@switch:~$ nv show router bgp
applied pending
------------------------------ ----------- -----------
enable on on
autonomous-system 65101 65101
router-id 10.10.10.1 10.10.10.1
policy-update-timer 5 5
graceful-shutdown off off
wait-for-install off off
graceful-restart
mode helper-only helper-only
restart-time 120 120
path-selection-deferral-time 360 360
stale-routes-time 360 360
convergence-wait
time 0 0
establish-wait-time 0 0
queue-limit
input 10000 10000
output 10000 10000
cumulus@switch:~$ sudo vtysh
...
switch# show ip bgp summary
ipv4 Unicast Summary
BGP router identifier 10.10.10.1, local AS number 65101 vrf-id 0
BGP table version 88
RIB entries 25, using 4800 bytes of memory
Peers 5, using 106 KiB of memory
Peer groups 1, using 64 bytes of memory
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
spine01(swp51) 4 65199 31122 31194 0 0 0 1d01h44m 7
spine02(swp52) 4 65199 31060 31151 0 0 0 01:47:13 7
spine03(swp53) 4 65199 31150 31207 0 0 0 01:48:31 7
spine04(swp54) 4 65199 31042 31098 0 0 0 01:46:57 7
leaf02(peerlink.4094) 4 65101 30919 30913 0 0 0 01:47:43 12
Total number of neighbors 5
To view the routing table as defined by BGP, run the vtysh show ip bgp ipv4 unicast command. For example:
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip bgp ipv4 unicast
BGP table version is 88, local router ID is 10.10.10.1, vrf id 0
Default local pref 100, local AS 65101
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
Network Next Hop Metric LocPrf Weight Path
* i10.0.1.1/32 peerlink.4094 0 100 0 ?
*> 0.0.0.0 0 32768 ?
*= 10.0.1.2/32 swp54 0 65199 65102 ?
*= swp52 0 65199 65102 ?
* i peerlink.4094 100 0 65199 65102 ?
*= swp53 0 65199 65102 ?
*> swp51 0 65199 65102 ?
*= 10.0.1.254/32 swp54 0 65199 65132 ?
*= swp52 0 65199 65132 ?
* i peerlink.4094 100 0 65199 65132 ?
*= swp53 0 65199 65132 ?
*> swp51 0 65199 65132 ?
*> 10.10.10.1/32 0.0.0.0 0 32768 ?
*>i10.10.10.2/32 peerlink.4094 0 100 0 ?
*= 10.10.10.3/32 swp54 0 65199 65102 ?
*= swp52 0 65199 65102 ?
* i peerlink.4094 100 0 65199 65102 ?
*= swp53 0 65199 65102 ?
*> swp51 0 65199 65102 ?
...
To show a more detailed breakdown of a specific neighbor, run the vtysh show ip bgp neighbor <neighbor> command or the NVUE nv show vrf <vrf> router bgp neighbor <neighbor> command:
cumulus@switch:~$ nv show vrf default router bgp neighbor swp51
operational applied
----------------------------- ------------------------- ----------
password *
enforce-first-as off
passive-mode off
nexthop-connected-check on
description none
bfd
enable off
ttl-security
enable on off
hops 1
local-as
enable off
timers
keepalive 3 auto
hold 9 auto
connection-retry 10 auto
route-advertisement none auto
address-family
ipv4-unicast
enable on
route-reflector-client off
route-server-client off
soft-reconfiguration off
nexthop-setting auto
add-path-tx off
attribute-mod
aspath off on
med off on
nexthop off on
...
To see details of a specific route, such as its source and destination, run the NVUE nv show vrf <vrf-id> router rib ipv4 route <route> or nv show vrf <vrf-id> router rib ipv6 route <route> command or the vtysh show ip bgp <route> command.
cumulus@switch:~$ nv show vrf default router rib ipv4 route 10.10.10.3/32
route-entry
==============
Protocol - Protocol name, TblId - Table Id, NHGId - Nexthop group Id, Flags - u
- unreachable, r - recursive, o - onlink, i - installed, d - duplicate, c -
connected, A - active
EntryIdx Protocol TblId NHGId Distance Metric ResolvedVia ResolvedViaIntf Weight Flags
-------- -------- ----- ----- -------- ------ ------------------------- --------------- ------ -----
1 bgp 254 132 20 0 fe80::4ab0:2dff:fe14:82a3 swp52 1 iA
fe80::4ab0:2dff:fe53:538c swp53 1 iA
fe80::4ab0:2dff:fea3:d534 swp54 1 iA
fe80::4ab0:2dff:feac:d7c4 swp51 1 iA
cumulus@switch:~$ sudo vtysh
...
switch# show ip bgp 10.10.10.3/32
GP routing table entry for 10.10.10.3/32
Paths: (5 available, best #5, table default)
Advertised to non peer-group peers:
spine01(swp51) spine02(swp52) spine03(swp53) spine04(swp54) leaf02(peerlink.4094)
65199 65102
fe80::8e24:2bff:fe79:7d46 from spine04(swp54) (10.10.10.104)
(fe80::8e24:2bff:fe79:7d46) (used)
Origin incomplete, valid, external, multipath
Last update: Wed Oct 7 13:13:13 2020
65199 65102
fe80::841:43ff:fe27:caf from spine02(swp52) (10.10.10.102)
(fe80::841:43ff:fe27:caf) (used)
Origin incomplete, valid, external, multipath
Last update: Wed Oct 7 13:13:14 2020
65199 65102
fe80::90b1:7aff:fe00:3121 from leaf02(peerlink.4094) (10.10.10.2)
Origin incomplete, localpref 100, valid, internal
Last update: Wed Oct 7 13:13:08 2020
65199 65102
fe80::48e7:fbff:fee9:5bcf from spine03(swp53) (10.10.10.103)
(fe80::48e7:fbff:fee9:5bcf) (used)
Origin incomplete, valid, external, multipath
Last update: Wed Oct 7 13:13:13 2020
65199 65102
fe80::7c41:fff:fe93:b711 from spine01(swp51) (10.10.10.101)
(fe80::7c41:fff:fe93:b711) (used)
Origin incomplete, valid, external, multipath, bestpath-from-AS 65199, best (Older Path)
Last update: Wed Oct 7 13:13:13 2020
Check BGP Timer Settings
To check BGP timers, such as the BGP keepalive interval, hold time, and advertisement interval, run the NVUE nv show vrf <vrf> router bgp neighbor <neighbor> timers command or the vtysh show ip bgp neighbor <peer> command. For example:
cumulus@leaf01:~$ nv show vrf default router bgp neighbor swp51 timers
operational applied
------------------- ----------- -------
keepalive 3 auto
hold 9 auto
connection-retry 10 auto
route-advertisement none auto
BGP Update Groups
You can show information about update group events or information about a specific IPv4 or IPv6 update group.
To show information about update group events, run the vtysh show bgp update-group command or run these NVUE commands:
nv show vrf <vrf-id> router bgp address-family ipv4-unicast update-groupfor IPv4nv show vrf <vrf-id> router bgp address-family ipv6-unicast update-groupfor IPv6
cumulus@leaf01:~$ nv show vrf default router bgp address-family ipv4-unicast update-group
RouteMap - Outbound route map, MinAdvInterval - Minimum route advertisement
interval, CreationTime - Time when the update group was created, LocalAsChange -
LocalAs changes for inbound route, Flags - r - replace-as, x - no-prepend
UpdateGrp RouteMap MinAdvInterval CreationTime LocalAsChange Flags
--------- -------- -------------- -------------------- ------------- -----
1 0 2024-07-08T18:00:57Z
3 0 2024-07-09T20:48:11Z
To show information about a specific update group, such as the number of peer refresh events, prune events, and packet queue length, run the vtysh show bgp update-group <group-id> command or run these NVUE commands:
nv show vrf <vrf-id> router bgp address-family ipv4-unicast update-group <group-id> -o jsonfor IPv4nv show vrf <vrf-id> router bgp address-family ipv6-unicast update-group <group-id> -o jsonfor IPv6
cumulus@leaf01:~$ nv show vrf default router bgp address-family ipv4-unicast update-group 1 -o json
{
"create-time": "2024-10-25T14:02:24Z",
"min-route-advertisement-interval": 0,
"sub-group": {
"1": {
"adjacency-count": 13,
"coalesce-time": 1300,
"counters": {
"join-events": 5,
"merge-check-events": 0,
"merge-events": 3,
"peer-refresh-events": 0,
"prune-events": 0,
"split-events": 0,
"switch-events": 0
},
"create-time": "2024-10-25T14:02:24Z",
"needs-refresh": "off",
"neighbor": {
"peerlink.4094": {},
"swp51": {},
"swp52": {},
"swp53": {},
"swp54": {}
},
"packet-counters": {
"queue-hwm-len": 2,
"queue-len": 0,
"queue-total": 14,
"total-enqueued": 14
},
"sub-group-id": 1,
"version": 18
}
},
"update-group-id": "1"
}
Show BGP Route Information
You can run NVUE commands to show route statistics for a BGP neighbor, such as the number of routes, and information about advertised and received routes.
To show the RIB table for IPv4 routes, run the nv show vrf <vrf> router rib ipv4 route command. To show the RIB table for IPv6 routes, run the nv show vrf <vrf> router rib ipv6 route command.
cumulus@leaf01:mgmt:~$ nv show vrf default router rib ipv4 route
Flags - * - selected, q - queued, o - offloaded, i - installed, S - fib-
selected, x - failed
Route Protocol Distance Uptime NHGId Metric Flags
--------------- --------- -------- -------------------- ----- ------ -----
10.1.10.0/24 connected 0 2024-07-18T21:57:29Z 46 0 *Sio
10.1.20.0/24 connected 0 2024-07-18T21:57:29Z 47 0 *Sio
10.1.30.0/24 connected 0 2024-07-18T21:57:29Z 48 0 *Sio
10.1.40.0/24 bgp 20 2024-07-18T22:02:22Z 57 0 *Si
10.1.50.0/24 bgp 20 2024-07-18T22:02:22Z 57 0 *Si
10.1.60.0/24 bgp 20 2024-07-18T22:02:22Z 57 0 *Si
10.10.10.1/32 connected 0 2024-07-18T21:55:54Z 7 0 *Sio
10.10.10.2/32 bgp 20 2024-07-18T21:57:29Z 34 0 *Si
10.10.10.3/32 bgp 20 2024-07-18T22:02:22Z 57 0 *Si
10.10.10.4/32 bgp 20 2024-07-18T22:02:27Z 57 0 *Si
10.10.10.101/32 bgp 20 2024-07-18T22:01:14Z 50 0 *Si
10.10.10.102/32 bgp 20 2024-07-18T22:02:22Z 58 0 *Si
To show the local RIB routes, run the nv show vrf <vrf> router bgp address-family ipv4-unicast route command for IPv4 or the nv show vrf <vrf> router bgp address-family ipv6-unicast route for IPv6. You can also run the command with -o json to show the received routes in json format.
cumulus@leaf02:~$ nv show vrf default router bgp address-family ipv4-unicast route PathCount - Number of paths present for the prefix, MultipathCount - Number of
paths that are part of the ECMP, DestFlags - * - bestpath-exists, w - fib-wait-
for-install, s - fib-suppress, i - fib-installed, x - fib-install-failed
Prefix PathCount MultipathCount DestFlags
--------------- --------- -------------- ---------
10.0.1.12/32 2 1 *
10.0.1.34/32 5 4 *
10.0.1.255/32 5 4 *
10.10.10.1/32 1 1 *
10.10.10.2/32 5 1 *
10.10.10.3/32 5 4 *
10.10.10.4/32 5 4 *
10.10.10.63/32 5 4 *
10.10.10.64/32 5 4 *
10.10.10.101/32 2 1 *
10.10.10.102/32 2 1 *
10.10.10.103/32 2 1 *
10.10.10.104/32 2 1 *
To show information about a specific local RIB route, run the nv show vrf <vrf> router bgp address-family ipv4-unicast route <route> for IPv4 or nv show vrf <vrf> router bgp address-family ipv6-unicast route <route> for IPv6.
The above IPv4 and IPv6 command shows the local RIB route information in brief format to improve performance for high scale environments. You can also run the command with -o json to show the received routes in json format.
cumulus@leaf01:~$ nv show vrf default router bgp address-family ipv4-unicast route 10.10.10.64/32
operational
--------------- -----------
path-count 5
multipath-count 4
path
=======
Origin - Route origin, Local - Locally originated route, Sourced - Sourced
route, Weight - Route weight, Metric - Route metric, LocalPref - Route local
preference, PathFrom - Route path origin, LastUpdate - Route last update,
NexthopCnt - Number of nexthops, Flags - = - multipath, * - bestpath, v - valid,
s - suppressed, R - removed, S - stale
Path Origin Local Sourced Weight Metric LocalPref PathFrom LastUpdate NexthopCnt Flags
---- ---------- ----- ------- ------ ------ --------- -------- -------------------- ---------- -----
1 incomplete external 2024-10-25T14:02:33Z 2 =*v
2 incomplete external 2024-10-25T14:02:42Z 2 =v
3 incomplete external 2024-10-25T14:02:36Z 2 =v
4 incomplete external 2024-10-25T14:02:36Z 2 =v
5 incomplete external 2024-10-25T14:02:33Z 2 *v
advertised-to
================
Neighbor hostname
------------- --------
peerlink.4094 leaf02
swp51 spine01
swp52 spine02
swp53 spine03
swp54 spine04
To show the route count, run the nv show vrf <vrf-id> router bgp neighbor <neighbor-id> address-family ipv4-unicast route-counters command for IPv4 or the nv show vrf <vrf-id> router bgp neighbor <neighbor-id> address-family ipv6-unicast route-counters for IPv6.
cumulus@leaf01:~$ nv show vrf default router bgp neighbor swp51 address-family ipv4-unicast route-counters
operational
-------------- -----------
route-count 8
adj-rib-in 0
damped 0
removed 0
history 0
stale 0
valid 8
all-rib 8
routes-counted 8
best-routes 7
usable 8
To show all advertised routes, run the nv show vrf <vrf> router bgp neighbor <neighbor> address-family ipv4-unicast advertised-routes command for IPv4 or the nv show vrf <vrf>> router bgp neighbor <neighbor> address-family ipv6-unicast advertised-routes for IPv6.
The above IPv4 and IPv6 command shows advertised routes in brief format to improve performance for high scale environments. You can also run the command with -o json to show the received routes in json format.
cumulus@leaf01:~$ nv show vrf default router bgp neighbor swp51 address-family ipv4-unicast advertised-routes
PathCount - Number of paths present for the prefix, MultipathCount - Number of
paths that are part of the ECMP
IPv4 Prefix PathCount MultipathCount DestFlags
--------------- --------- -------------- ---------------
10.1.10.0/24 3 1 bestpath-exists
10.1.20.0/24 3 1 bestpath-exists
10.1.30.0/24 3 1 bestpath-exists
10.1.40.0/24 3 2 bestpath-exists
10.1.50.0/24 3 2 bestpath-exists
10.1.60.0/24 3 2 bestpath-exists
10.10.10.1/32 2 1 bestpath-exists
10.10.10.2/32 3 1 bestpath-exists
10.10.10.3/32 3 2 bestpath-exists
10.10.10.4/32 3 2 bestpath-exists
10.10.10.101/32 2 1 bestpath-exists
10.10.10.102/32 2 1 bestpath-exists
To show information about a specific advertised route, run thenv show <vrf> default router bgp neighbor <neighbor> address-family ipv4-unicast advertised-routes <route> for IPv4 or nv show <vrf> default router bgp neighbor <neighbor> address-family ipv6-unicast advertised-routes <route> for IPv6.
cumulus@leaf01:~$ nv show vrf default router bgp neighbor swp51 address-family ipv4-unicast advertised-route 10.10.10.1/32
operational
--------------- -----------
path-count 2
multipath-count 1
path
====================
Origin - Route origin, Local - Locally originated route, Sourced - Sourced
route, Weight - Route weight, Metric - Route metric, LocalPref - Route local
preference, PathFrom - Route path origin, LastUpdate - Route last update,
NexthopCnt - Number of nexthops, Flags - = - multipath, * - bestpath, v - valid,
s - suppressed, R - removed, S - stale
Path Origin Local Sourced Weight Metric LocalPref PathFrom LastUpdate NexthopCnt Flags
---- ---------- ----- ------- ------ ------ --------- -------- -------------------- ---------- -----
1 IGP on on 32768 0 2024-07-18T21:55:54Z 1 *v
2 incomplete on 32768 0 2024-07-18T21:55:54Z 1 v
...
To show all the received routes, run the nv show vrf <vrf> router bgp neighbor <neighbor> address-family ipv4-unicast received-routes command for IPv4 or nv show vrf <vrf> router bgp neighbor <neighbor> address-family ipv6-unicast received-routes command for IPv6. These commands show received routes in brief format to improve performance for high scale environments. You can also run the command with --view=detail to see more detailed information or with -o json to show the received routes in json format.
To show information about a specific received route, run the nv show vrf <vrf> router bgp neighbor <neighbor> address-family ipv4-unicast received-routes <route> -o json for IPv4 or nv show vrf <vrf> router bgp neighbor <neighbor> address-family ipv6-unicast received-routes <route> -o json for IPv6.
Show Next Hop Information
To show a summary of all the BGP IPv4 or IPv6 next hops, run the nv show vrf <vrf> router bgp nexthop ipv4 or nv show vrf <vrf> router bgp nexthop ipv6 command. The output shows the IGP metric, the number of paths pointing to a next hop, and the address or interface used to reach a next hop.
cumulus@leaf01:mgmt:~$ nv show vrf default router bgp nexthop ipv4
Nexthops
===========
PathCnt - Number of paths pointing to this Nexthop, ResolvedVia - Resolved via
address or interface, Interface - Resolved via interface
Address IGPMetric Valid PathCnt ResolvedVia Interface
----------- --------- ----- ------- ------------------------- -------------
10.0.1.34 0 on 160 fe80::4ab0:2dff:fe60:910e swp54
fe80::4ab0:2dff:fea7:7852 swp53
fe80::4ab0:2dff:fec8:8fb9 swp52
fe80::4ab0:2dff:feff:e147 swp51
10.10.10.2 0 on 15 fe80::4ab0:2dff:fe2d:495c peerlink.4094
10.10.10.3 0 on 15 fe80::4ab0:2dff:fe60:910e swp54
fe80::4ab0:2dff:fea7:7852 swp53
fe80::4ab0:2dff:fec8:8fb9 swp52
fe80::4ab0:2dff:feff:e147 swp51
10.10.10.4 0 on 15 fe80::4ab0:2dff:fe60:910e swp54
fe80::4ab0:2dff:fea7:7852 swp53
fe80::4ab0:2dff:fec8:8fb9 swp52
fe80::4ab0:2dff:feff:e147 swp51
10.10.10.63 0 on 15 fe80::4ab0:2dff:fe60:910e swp54
fe80::4ab0:2dff:fea7:7852 swp53
fe80::4ab0:2dff:fec8:8fb9 swp52
fe80::4ab0:2dff:feff:e147 swp51
10.10.10.64 0 on 15 fe80::4ab0:2dff:fe60:910e swp54
fe80::4ab0:2dff:fea7:7852 swp53
fe80::4ab0:2dff:fec8:8fb9 swp52
fe80::4ab0:2dff:feff:e147 swp51
To show information about a specific next hop, run the vtysh NVUE nv show vrf <vrf-id> router bgp nexthop ipv4 ip-address <ip-address> command for IPv4 or nv show vrf <vrf-id> router bgp nexthop ipv6 ip-address <ip-address> for IPv6. You can also run the vtysh show bgp vrf default nexthop <ip-address> command.
cumulus@leaf01:mgmt:~$ nv show vrf default router bgp nexthop ipv4 ip-address 10.10.10.2
operational
---------------- -------------------------
valid yes
complete on
igp-metric 0
path-count 15
last-update-time 2024-10-25T14:02:32Z
[resolved-via] fe80::4ab0:2dff:fee8:57ba
To show through which address and interface BGP resolves a specific next hop, run the nv show vrf <vrf-id> router bgp nexthop ipv4 ip-address <ip-address-id> resolved-via command for IPv4 or the nv show vrf <vrf-id> router bgp nexthop ipv6 ip-address <ip-address-id> resolved-via command for IPv6.
cumulus@leaf01:~$ nv show vrf default router bgp nexthop ipv4 ip-address 10.10.10.2 resolved-via
Nexthop interface
------------------------- ---------
fe80::4ab0:2dff:fe20:ac25 swp51
fe80::4ab0:2dff:fe93:d92d swp52
Troubleshoot BGP Unnumbered
To verify that FRR learns the neighboring link-local IPv6 address through the IPv6 neighbor discovery router advertisements on a given interface, run the vtysh show interface <interface> command.
If you do not enable ipv6 nd suppress-ra on both ends of the interface, Neighbor address(s): shows the link-local address of the other end (the address that BGP uses when that interface uses BGP).
Cumulus Linux automatically enables IPv6 route advertisements (RAs) on an interface with IPv6 addresses. You do not need to run the no ipv6 nd suppress-ra command for BGP unnumbered.
cumulus@switch:~$ sudo vtysh
...
switch# show interface swp51
Interface swp51 is up, line protocol is up
Link ups: 0 last: (never)
Link downs: 0 last: (never)
PTM status: disabled
vrf: default
OS Description: leaf to spine
index 8 metric 0 mtu 9216 speed 1000
flags: <UP,BROADCAST,RUNNING,MULTICAST>
Type: Ethernet
HWaddr: 10:d8:68:d4:a6:81
inet6 fe80::12d8:68ff:fed4:a681/6
Interface Type Other
protodown: off
ND advertised reachable time is 0 milliseconds
ND advertised retransmit interval is 0 milliseconds
ND advertised hop-count limit is 64 hops
ND router advertisements sent: 217 rcvd: 216
ND router advertisements are sent every 10 seconds
ND router advertisements lifetime tracks ra-interval
ND router advertisement default router preference is medium
Hosts use stateless autoconfig for addresses.
Neighbor address(s):
inet6 fe80::f208:5fff:fe12:cc8c/128
Troubleshoot IPv4 Prefixes Learned with IPv6 Next Hops
To show IPv4 prefixes learned with IPv6 next hops, run the following commands.
The following examples show an IPv4 prefix learned from a BGP peer over an IPv6 session using IPv6 global addresses, but where the next hop installed by BGP is a link-local IPv6 address. This occurs when the session is directly between peers, and the BGP update for the prefix includes both link-local and global IPv6 addresses as next hops. If both global and link-local next hops exist, BGP prefers the link-local address for route installation.
cumulus@spine01:mgmt:~$ sudo vtysh
...
spine01# show ip bgp ipv4 unicast summary
BGP router identifier 10.10.10.101, local AS number 65199 vrf-id 0
BGP table version 3
RIB entries 3, using 576 bytes of memory
Peers 1, using 21 KiB of memory
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
leaf01(2001:db8:2::a00:1) 4 65101 22 22 0 0 0 00:01:00 0
Total number of neighbors 1
cumulus@spine01:mgmt:~$ sudo vtysh
...
spine01# show ip bgp ipv4 unicast
BGP table version is 3, local router ID is 10.10.10.101, vrf id 0
Default local pref 100, local AS 65199
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
Network Next Hop Metric LocPrf Weight Path
10.10.10.101/32 fe80::a00:27ff:fea6:b9fe 0 0 32768 i
Displayed 1 routes and 1 total paths
cumulus@spine01:~$ sudo vtysh
...
spine01# show ip bgp ipv4 unicast 10.10.10.101/32
BGP routing table entry for 10.10.10.101/32
Paths: (1 available, best #1, table default)
Advertised to non peer-group peers:
Leaf01(2001:db8:0002::0a00:1)
3
2001:db8:0002::0a00:1 from Leaf01(2001:db8:0002::0a00:1) (10.10.10.101)
(fe80::a00:27ff:fea6:b9fe) (used)
Origin IGP, metric 0, valid, external, bestpath-from-AS 3, best (First path received)
AddPath ID: RX 0, TX 3
Last update: Mon Oct 22 08:09:22 2018
The example output below shows the results of installing the route in the FRR RIB as well as the kernel FIB. The next hop installed in the FRR RIB is the link-local IPv6 address, which Cumulus Linux converts into an IPv4 link-local address, as required for installation into the kernel FIB.
cumulus@spine01:~$ sudo vtysh
...
spine01# show ip route 10.10.10.101/32
RIB entry for 10.10.10.101/32
===========================
Routing entry for 10.10.10.101/32
Known via "bgp", distance 20, metric 0, best
Last update 2d17h05m ago
* fe80::a00:27ff:fea6:b9fe, via swp1
FIB entry for 10.10.10.101/32
===========================
10.10.10.101/32 via 10.0.1.0 dev swp1 proto bgp metric 20 onlink
If BGP learns an IPv4 prefix with only an IPv6 global next hop address (when it learns the route through a route reflector), the command output shows the IPv6 global address as the next hop value. The command also shows that it learns recursively through the link-local address of the route reflector. When you use a global IPv6 address as a next hop for route installation in the FRR RIB, the switch still converts it into an IPv4 link-local address for installation into the kernel.
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip bgp ipv4 unicast summary
BGP router identifier 10.10.10.1, local AS number 65101 vrf-id 0
BGP table version 1
RIB entries 1, using 152 bytes of memory
Peers 1, using 19 KiB of memory
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
Spine01(2001:db8:0002::0a00:2) 4 1 74 68 0 0 0 00:00:45 1
Total number of neighbors 1
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip bgp ipv4 unicast summary
BGP table version is 1, local router ID is 10.10.10.1
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i10.1.10.0/24 2001:2:2::4 0 100 0 i
Displayed 1 routes and 1 total paths
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip bgp ipv4 unicast 10.10.10.101/32
BGP routing table entry for 10.10.10.101/32
Paths: (1 available, best #1, table default)
Not advertised to any peer
Local
2001:2:2::4 from Spine01(2001:1:1::1) (10.10.10.104)
Origin IGP, metric 0, localpref 100, valid, internal, bestpath-from-AS Local, best (First path received)
Originator: 10.0.0.14, Cluster list: 10.10.10.111
AddPath ID: RX 0, TX 5
Last update: Mon Oct 22 14:25:30 2018
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip route 10.10.10.1/32
RIB entry for 10.10.10.1/32
===========================
Routing entry for 10.10.10.1/32
Known via "bgp", distance 200, metric 0, best
Last update 00:01:13 ago
2001:2:2::4 (recursive)
* fe80::a00:27ff:fe5a:84ae, via swp1
FIB entry for 10.10.10.1/32
===========================
10.10.10.1/32 via 10.0.1.1 dev swp1 proto bgp metric 20 onlink
To only use IPv6 global addresses for route installation into the FRR RIB, you must add an additional route map to the neighbor or peer group statement in the appropriate address family. When the route map command set ipv6 next-hop prefer-global applies to a neighbor, if both a link-local and global IPv6 address are in the BGP update for a prefix, BGP uses the IPv6 global address for route installation.
With this additional configuration, the output in the FRR RIB changes in the direct neighbor case as shown below:
router bgp 65101
bgp router-id 10.10.10.1
neighbor 2001:db8:2::a00:1 remote-as internal
neighbor 2001:db8:2::a00:1 capability extended-nexthop
!
address-family ipv4 unicast
neighbor 2001:db8:2::a00:1 route-map GLOBAL in
exit-address-family
!
route-map GLOBAL permit 20
set ipv6 next-hop prefer-global
!
The resulting FRR RIB output is as follows:
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
F - PBR,
> - selected route, * - FIB route
B 0.0.0.0/0 [200/0] via 2001:2:2::4, swp2, 00:01:00
K 0.0.0.0/0 [0/0] via 10.0.2.2, eth0, 1d02h29m
C>* 10.0.0.9/32 is directly connected, lo, 5d18h32m
C>* 10.0.2.0/24 is directly connected, eth0, 03:51:31
B>* 172.16.4.0/24 [200/0] via 2001:2:2::4, swp2, 00:01:00ß
C>* 172.16.10.0/24 is directly connected, swp3, 5d18h32m
When the switch learns the route through a route reflector, it appears like this:
router bgp 65101
bgp router-id 10.10.10.1
neighbor 2001:db8:2::a00:2 remote-as internal
neighbor 2001:db8:2::a00:2 capability extended-nexthop
!
address-family ipv6 unicast
neighbor 2001:db8:2::a00:2 activate
neighbor 2001:db8:2::a00:2 route-map GLOBAL in
exit-address-family
!
route-map GLOBAL permit 10
set ipv6 next-hop prefer-global
cumulus@leaf01:~$ sudo vtysh
...
leaf01# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
F - PBR,
> - selected route, * - FIB route
B 0.0.0.0/0 [200/0] via 2001:2:2::4, 00:00:01
K 0.0.0.0/0 [0/0] via 10.0.2.2, eth0, 3d00h26m
C>* 10.0.0.8/32 is directly connected, lo, 3d00h26m
C>* 10.0.2.0/24 is directly connected, eth0, 03:39:18
C>* 172.16.3.0/24 is directly connected, swp2, 3d00h26m
B> 172.16.4.0/24 [200/0] via 2001:2:2::4 (recursive), 00:00:01
* via 2001:1:1::1, swp1, 00:00:01
C>* 172.16.10.0/24 is directly connected, swp3, 3d00h26m
Neighbor State Change Log
Cumulus Linux records the changes that a neighbor goes through in syslog and in the /var/log/frr/frr.log file. For example:
020-10-05T15:51:32.621773-07:00 leaf01 bgpd[10104]: %NOTIFICATION: sent to neighbor peerlink.4094 6/7 (Cease/Connection collision resolution) 0 bytes
2020-10-05T15:51:32.623023-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor peerlink.4094(leaf02) in vrf default Up
2020-10-05T15:51:32.623156-07:00 leaf01 bgpd[10104]: %NOTIFICATION: sent to neighbor peerlink.4094 6/7 (Cease/Connection collision resolution) 0 bytes
2020-10-05T15:51:32.623496-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor peerlink.4094(leaf02) in vrf default Down No AFI/SAFI activated for peer
2020-10-05T15:51:33.040332-07:00 leaf01 bgpd[10104]: [EC 33554454] swp53 [Error] bgp_read_packet error: Connection reset by peer
2020-10-05T15:51:33.279468-07:00 leaf01 bgpd[10104]: [EC 33554454] swp52 [Error] bgp_read_packet error: Connection reset by peer
2020-10-05T15:51:33.339487-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor swp54(spine04) in vrf default Up
2020-10-05T15:51:33.340893-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor swp53(spine03) in vrf default Up
2020-10-05T15:51:33.341648-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor swp52(spine02) in vrf default Up
2020-10-05T15:51:33.342369-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor swp51(spine01) in vrf default Up
2020-10-05T15:51:33.627958-07:00 leaf01 bgpd[10104]: %ADJCHANGE: neighbor peerlink.4094(leaf02) in vrf default Up
Clear BGP Routes
NVUE provides commands to clear and refresh routes in the BGP table. You can clear all routes in the BGP table or all routes for an address family (IPv4, IPv6, or EVPN) in a VRF.
The BGP clear commands do not clear counters in the kernel or hardware.
- BGP clear route commands that specify a direction (
inorout) do not reset BGP neighbor adjacencies. - When the switch has a neighbor configured with
soft-reconfiguration inboundenabled, performing a clear in or soft clear in clears the routes in the soft reconfiguration table for the address family. This results in reevaluating routes in the BGP table against any applied input policies. - When the switch has a neighbor configured without the
soft-reconfiguration inboundoption enabled, performing a clear in or soft in sends the peer a route refresh message. - Outbound BGP clear commands (either out or soft out) readvertise all routes to BGP peers.
- BGP soft clear commands that do not specify a direction (
inorout) do not reset BGP neighbor adjacencies, and affect both inbound and outbound routes, as described above, depending on if you enablesoft-reconfiguration inbound.
To clear and refresh all IPv4 inbound routes:
cumulus@leaf01:~$ nv action clear vrf default router bgp address-family ipv4-unicast soft in
To clear and resend all IPv6 outbound routes:
cumulus@leaf01:~$ nv action clear vrf default router bgp address-family ipv6-unicast soft out
To clear and refresh all EVPN inbound routes:
cumulus@leaf01:~$ nv action clear vrf default router bgp address-family l2vpn-evpn soft in
To clear and resend all outbound IPv4 routes:
cumulus@leaf01:~$ nv action clear vrf default router bgp address-family ipv4-unicast soft out
To clear and resend all IPv6 outbound routes to BGP neighbor 10.10.10.101:
cumulus@leaf01:~$ nv action clear vrf default router bgp neighbor 10.10.10.101 address-family ipv6-unicast out
To clear and resend outbound routes for all address families (IPv4, IPv6, and l2vpn-evpn) for the BGP peer group SPINES:
cumulus@leaf01:~$ nv action clear vrf default router bgp peer-group SPINES out
To clear and refresh all IPv4 inbound routes for all VRFs and address families:
cumulus@switch:~$ nv action clear router bgp soft in
Action succeeded
To clear and refresh inbound routes for all neighbors, address families, and VRFs and to refresh the outbound route filtering prefix-list:
cumulus@switch:~$ nv action clear router bgp in prefix-filter
Action succeeded
To clear BGP sessions with all neighbors, forcing the neighbors to restart:
cumulus@switch:~$ nv action clear router bgp
Action succeeded
To clear and refresh all IPv4 inbound routes:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default ipv4 unicast * soft in
switch# exit
To clear and resend all IPv6 outbound routes:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default ipv6 unicast * soft out
switch# exit
To clear and refresh all EVPN inbound routes:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default l2vpn evpn * soft in
switch# exit
To clear and resend all outbound IPv4 routes:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default ipv4 unicast * soft out
switch# exit
To clear and resend all IPv6 outbound routes to BGP neighbor 10.10.10.101:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default ipv6 unicast 10.10.10.101 out
switch# exit
To clear and resend outbound routes for all address families (IPv4, IPv6, and l2vpn-evpn) for the BGP peer group SPINES:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp vrf default peer-group SPINES out
switch# exit
To clear and refresh inbound routes for all neighbors, address families, and VRFs and to refresh the outbound route filtering prefix-list:
cumulus@spine01:~$ sudo vtysh
...
switch# clear bgp in prefix-filter
switch# exit
To clear BGP sessions with all neighbors, forcing the neighbors to restart:
cumulus@switch:~$ sudo vtysh
...
switch# clear bgp *
switch# write memory
switch# exit