Hi,
I've made some tests on ldpd and found some problems/strange things with the
following configuration:
2 hosts (v 5.0)
- core3 (loopback 10.0.0.7)
- core1 (loopback 10.0.0.9)
2 links between these 2 hosts:
- vlan211 (on em9)
core3 IP: 10.0.0.125
core1 IP: 10.0.0.126
- vlan212 (on em5)
core3 IP: 10.0.0.121
core1 IP: 10.0.0.122
I've keeped only interesting part in command results (there some other ospf
neighbors and interfaces). Sorry for this long post, I wanted to reproduce a
problem I've got one time but failed to get it again (see a the end of this
email).
ospf is running on both hosts:
core3:
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:34 10.0.0.122 vlan212 00:24:38
10.0.0.9 1 FULL/DR 00:00:34 10.0.0.126 vlan211 00:23:27
core1:
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:31 10.0.0.121 vlan212 00:24:50
10.0.0.7 1 FULL/BCKUP 00:00:31 10.0.0.125 vlan211 00:23:40
ldpd.conf on core3:
<<
router-id 10.0.0.7
distribution independent
retention liberal
advertisement unsolicited
interface vlan212
interface vlan211
>>
same on core1 except that router-id is 10.0.0.9
--------------------------------
I start ldpd on 2 hosts:
core3 logs:
Sep 8 14:04:59 core3 ldpd[5529]: startup
Sep 8 14:05:00 core3 ldpd[5529]: mpath route not found
Sep 8 14:05:05 core3 ldpd[30289]: Connection attempt from unknown neighbor
10.0.0.126: NO HELLO
core1 logs:
Sep 8 14:04:54 core1 ldpd[8601]: startup
Sep 8 14:04:55 core1 ldpd[17310]: received notification from neighbor
10.0.0.7: Session Rejected, No Hello
ldpd seems confused by notification received from same host on different
links.
root@core3:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.9 OPERATIONAL/ACTIVE 10.0.0.126 vlan211 00:00:09
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 OPERATIONAL/ACTIVE 10.0.0.125 vlan211 00:00:13
===> First problem: only routes from one interface are tagged:
root@core1:etc$ ldpctl sh l
Destination Nexthop Local Label Remote Label In Use
....
10.200.0.176/29 10.0.0.121 56 33 yes
10.200.0.176/29 10.0.0.125 56 Untagged yes
10.100.0.0/24 10.0.0.121 62 39 yes
10.100.0.0/24 10.0.0.125 62 Untagged yes
Tagged interface correspond to interface in fib:
root@core1:etc$ route -n get 10.100.0.1
route to: 10.100.0.1
destination: 10.100.0.0
mask: 255.255.255.0
gateway: 10.0.0.121
interface: vlan212
if address: 10.0.0.122
mpls label: PUSH 39
priority: 32 (ospf)
flags: <UP,GATEWAY,DONE,MPATH,MPLS>
use mtu expire
72 0 0
--------------------------------
Now I shutdown vlan211 on core1 with "ifconfig vlan211 down"
No logs on core3
on core1:
Sep 8 14:15:03 core1 ldpd[17310]: interface vlan211 down
Sep 8 14:15:03 core1 ospfd[23127]: send_packet: error sending packet on
interface vlan211: Network is down
Sep 8 14:15:03 core1 ospfd[23127]: interface vlan211 down
Sep 8 14:15:07 core1 ldpd[17310]: send_packet: error sending packet on
interface vlan211: Network is down
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:36 10.0.0.122 vlan212 00:37:17
10.0.0.9 1 DOWN/OTHER 00:00:54 10.0.0.126 vlan211 -
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:33 10.0.0.121 vlan212 00:37:08
10.0.0.7 1 DOWN/DOWN 00:01:18 10.0.0.125 vlan211 -
root@core3:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.9 OPERATIONAL/ACTIVE 10.0.0.126 vlan211 00:11:40
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 OPERATIONAL/DOWN 10.0.0.125 vlan211 00:11:35
--------------------------------
Next I restore vlan211 with "ifconfig vlan211 up"
no logs on core3
on core1:
Sep 8 14:17:45 core1 ldpd[17310]: interface vlan211 up
Sep 8 14:17:45 core1 ospfd[23127]: interface vlan211 up
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:37 10.0.0.122 vlan212 00:39:06
10.0.0.9 1 FULL/DR 00:00:37 10.0.0.126 vlan211 00:00:23
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:34 10.0.0.121 vlan212 00:39:28
10.0.0.7 1 FULL/BCKUP 00:00:34 10.0.0.125 vlan211 00:00:45
--------------------------------
and shut down vlan212 on core1 with "ifconfig vlan212 down"
Sep 8 14:19:09 core1 ospfd[23127]: interface vlan212 down
Sep 8 14:19:09 core1 ldpd[17310]: interface vlan212 down
Sep 8 14:19:12 core1 ldpd[17310]: send_packet: error sending packet on
interface vlan212: Network is down
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 DOWN/OTHER 00:00:01 10.0.0.122 vlan212 -
10.0.0.9 1 FULL/DR 00:00:39 10.0.0.126 vlan211 00:01:51
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 DOWN/DOWN 00:00:58 10.0.0.121 vlan212 -
10.0.0.7 1 FULL/BCKUP 00:00:39 10.0.0.125 vlan211 00:02:11
root@core3:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.9 OPERATIONAL/ACTIVE 10.0.0.126 vlan211 00:16:02
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 OPERATIONAL/ACTIVE 10.0.0.125 vlan211 00:15:53
--------------------------------
next restore vlan212 with "ifconfig vlan212 up"
Sep 8 14:21:59 core1 ospfd[23127]: interface vlan212 up
Sep 8 14:21:59 core1 ldpd[17310]: interface vlan212 up
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:38 10.0.0.122 vlan212 00:00:31
10.0.0.9 1 FULL/DR 00:00:38 10.0.0.126 vlan211 00:04:42
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:36 10.0.0.121 vlan212 00:00:23
10.0.0.7 1 FULL/BCKUP 00:00:36 10.0.0.125 vlan211 00:04:33
--------------------------------
now shutdown vlan211 on core1 with "ifconfig vlan211 down"
Sep 8 14:23:08 core1 ospfd[23127]: send_packet: error sending packet on
interface vlan211: Network is down
Sep 8 14:23:08 core1 ospfd[23127]: interface vlan211 down
Sep 8 14:23:12 core1 ldpd[17310]: send_packet: error sending packet on
interface vlan211: Network is down
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:37 10.0.0.122 vlan212 00:02:02
10.0.0.9 1 DOWN/OTHER 00:00:23 10.0.0.126 vlan211 -
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:30 10.0.0.121 vlan212 00:01:49
10.0.0.7 1 DOWN/DOWN 00:00:47 10.0.0.125 vlan211 -
--------------------------------
and kill ldpd on core1
Sep 8 14:24:36 core1 ldpd[17310]: if_leave_group: error IP_DROP_MEMBERSHIP,
interface vlan211 address 224.0.0.2: Can't assign requested address
Sep 8 14:24:36 core1 ldpd[30241]: label decision engine exiting
Sep 8 14:24:36 core1 ldpd[17310]: if_act_reset: error leaving group
224.0.0.2, interface vlan211
Sep 8 14:24:36 core1 ldpd[17310]: ldp engine exiting
Sep 8 14:24:36 core1 ospfd[7111]: mpath route not found
Sep 8 14:24:36 core1 ospfd[7111]: alien OSPF route 10.0.0.120/30
Sep 8 14:24:37 core1 ldpd[8601]: kernel routing table decoupled
Sep 8 14:24:37 core1 ldpd[8601]: terminating
--------------------------------
now restart ldpd on core1
core3 logs:
Sep 8 14:25:33 core3 ldpd[30289]: Connection attempt from unknown neighbor
10.0.0.122: NO HELLO
Sep 8 14:25:48 core3 ldpd[5529]: send_rtmsg: action 3, AF 2, prefix
10.0.0.124/30: No such process
core1 logs:
Sep 8 14:25:18 core1 ldpd[30027]: startup
Sep 8 14:25:23 core1 ldpd[11155]: received notification from neighbor
10.0.0.7: Session Rejected, No Hello
root@core3:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.9 OPERATIONAL/ACTIVE 10.0.0.122 vlan212 00:00:41
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 OPERATIONAL/ACTIVE 10.0.0.121 vlan212 00:00:54
--------------------------------
next do a "ifconfig vlan211 up" on core1:
core3 logs: nothing
core1 logs
Sep 8 14:27:30 core1 ldpd[11155]: interface vlan211 up
Sep 8 14:27:30 core1 ospfd[23127]: interface vlan211 up
--------------------------------
And now "ifconfig em5 down" on core1 (em5 is vlan212 parent interface)
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 DOWN/OTHER 00:00:24 10.0.0.122 vlan212 -
10.0.0.9 1 FULL/DR 00:00:36 10.0.0.126 vlan211 00:01:44
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 DOWN/OTHER 00:00:37 10.0.0.121 vlan212 -
10.0.0.7 1 FULL/BCKUP 00:00:34 10.0.0.125 vlan211 00:01:55
root@core3:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.11 OPERATIONAL/ACTIVE 10.0.0.49 vlan208 00:23:59
10.0.0.12 OPERATIONAL/ACTIVE 10.0.0.106 vlan216 00:24:12
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
===> lpdctl say there's no more neighbor but ldpd table still have
taggued routes:
core1: ldpctl sh l
Destination Nexthop Local Label Remote Label In Use
...
10.200.0.176/29 10.0.0.125 57 33 yes
10.100.0.0/24 10.0.0.125 63 39 yes
root@core1:etc$ route -n get 10.100.0.1
route to: 10.100.0.1
destination: 10.100.0.0
mask: 255.255.255.0
gateway: 10.0.0.125
interface: vlan211
if address: 10.0.0.126
mpls label: PUSH 39
priority: 32 (ospf)
flags: <UP,GATEWAY,DONE,MPLS>
use mtu expire
0 0 0
sockaddrs: <DST,GATEWAY,NETMASK,IFP,IFA,SRC>
I've verified: packets from core 1 to 10.100.0.1 are well pushed on vlan211
with mpls label 39.
--------------------------------
Next "ifconfig em5 up" on core1
core3 logs:
Sep 8 14:36:57 core3 ldpd[30289]: Connection attempt from unknown neighbor
10.0.0.122: NO HELLO
Sep 8 14:37:13 core3 ospfd[15426]: mpath route not found
Sep 8 14:37:13 core3 ospfd[15426]: alien OSPF route 10.0.0.124/30
core1 logs:
Sep 8 14:36:48 core1 ldpd[11155]: received notification from neighbor
10.0.0.7: Session Rejected, No Hello
root@core3:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.9 1 FULL/DR 00:00:38 10.0.0.122 vlan212 00:01:21
10.0.0.9 1 FULL/DR 00:00:37 10.0.0.126 vlan211 00:10:34
root@core1:etc$ ospfctl sh nei
ID Pri State DeadTime Address Iface Uptime
10.0.0.7 1 FULL/BCKUP 00:00:36 10.0.0.121 vlan212 00:01:34
10.0.0.7 1 FULL/BCKUP 00:00:34 10.0.0.125 vlan211 00:10:46
root@core3:etc$ ldpctl show nei
ID State Address Iface Uptime
10.0.0.9 OPERATIONAL/ACTIVE 10.0.0.122 vlan212 00:00:49
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 OPERATIONAL/ACTIVE 10.0.0.121 vlan212 00:00:39
root@core1:etc$ ldpctl sh
Destination Nexthop Local Label Remote Label In Use
...
10.200.0.176/29 10.0.0.125 57 33 yes
10.200.0.176/29 10.0.0.121 57 33 yes
10.100.0.0/24 10.0.0.125 63 39 yes
10.100.0.0/24 10.0.0.121 63 39 yes
==> now both interfaces are tagged !
The problem I've try to reproduce was:
ldpd on core3 is using vlan212 to contact ldpd on core1 but core1 is doing
the same thing on the other vlan (vlan211). So ldp sessions can't be
establisehed. In the case ldpdctl sh nei diplayed something like:
root@core3:etc$ ldpctl show nei
ID State Address Iface Uptime
10.0.0.9 --Can't remember-- 10.0.0.126 vlan212 -
root@core1:etc$ ldpctl sh nei
ID State Address Iface Uptime
10.0.0.7 --Can't remember-- 10.0.0.121 vlan211 -
with each host logs saying Connection attempt from unknown neighbor
... NO HELLO
Manuel
