[Xorp-users] OSPF Hello messages not exchanged after some period, and link status becomes dead

Dejan Petkovic dexpetkovic at gmail.com
Tue Mar 23 15:49:17 PDT 2010


On Tue, Mar 23, 2010 at 5:33 PM, Ben Greear <greearb at candelatech.com> wrote:
> On 03/23/2010 12:41 AM, Dejan Petkovic wrote:
>>
>> Hello,
>>
>> I am running multiple XORP OSPF routers on OpenVZ virtual machines.
>> When I start the xorp routers on all virtual machines, the links go up
>> and OSPF adjacencies are established. However, after some time, both
>> parameters Pri and Dead in the show ospf4 neighbor command output give
>> value 0, and the link status is down.
>>
>> I have set on host and virtual machines forwarding and proxy_arp
>> settings to 1. I have set that hello interval is 10 seconds, and that
>> router dead interval is 200 seconds.
>>
>> When I restart the xorp instances running on virtual machines, the
>> adjacencies are again established and the routers can ping each other.
>> I suspect the arp issue here, as the arp table of the nodes on which
>> the XORP is running becomes empty at the moment when hello messages
>> stop to arrive to the appropriate xorp routers. However, if it was an
>> arp issue, xorp restart shouldn't affect the behavior?
>>
>> The sample configuration of two adjacent routers is pasted below. Only
>> IPs would differ. Where am I making a mistake? Perhaps I have not
>> configured correctly the link between these two routers (Please
>> neglect the fact that I used C class there)?
>
> What version of xorp are you using?
>
> Please send us output of these cmds for both nodes
> when it is in failure mode.
>
> ip ru show
> ip route show
> ip addr show
> ip neigh show
>
> You could try sniffing to see if arp requests are being properly
> sent/received and see if they are being answered.
>
> Thanks,
> Ben
>
> --
> Ben Greear <greearb at candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>
>

Hi Ben,

the thing is, when the routers on both nodes are in down mode, the
suggested commands can not be executed on the nodes. They simply do
not return any result, i.e. I have to break the command. However,
after I kill xorp rtrmgr script on both nodes, I get the below output
from the suggested commands. The XORP version I use is 1.6.

Please note that venet0 entries in the routing tables should be
ignored. Perhaps I should disable venet interface, as it might cause
tis behavior?

I have also pasted the output of the commands before the hello packet
exchange seizes, i.e. while the adjacency still exists between the
nodes.

Thank you very much for your help and have a great day,

Dejan



****************************************************
[root at srv1 /]# ip ru show
0:      from all lookup 255
32766:  from all lookup main
32767:  from all lookup default

[root at srv1 /]# ip route show
79.10.0.0/24 dev eth1  proto kernel  scope link  src 79.10.0.1
79.0.0.0/24 dev eth0  proto kernel  scope link  src 79.0.0.1
192.0.2.0/24 dev venet0  scope host
169.254.0.0/16 dev venet0  scope link
default via 192.0.2.1 dev venet0

[root at srv1 /]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/void
    inet 127.0.0.1/32 scope host venet0
    inet 192.168.1.101/32 brd 192.168.1.101 scope global venet0:0
5: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:69:63:aa brd ff:ff:ff:ff:ff:ff
    inet 79.0.0.1/24 brd 79.0.0.255 scope global eth0
    inet6 fe80::218:51ff:fe69:63aa/64 scope link
       valid_lft forever preferred_lft forever
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:34:bb:fd brd ff:ff:ff:ff:ff:ff
    inet 79.10.0.1/24 brd 79.10.0.255 scope global eth1
    inet6 fe80::218:51ff:fe34:bbfd/64 scope link
       valid_lft forever preferred_lft forever

[root at srv1 /]# ip neigh show
79.10.0.2 dev eth1 lladdr 00:18:51:32:66:1c REACHABLE


[root at srv2 /]# ip ru show
0:      from all lookup 255
32766:  from all lookup main
32767:  from all lookup default

[root at srv2 /]# ip neigh show
79.10.0.1 dev eth1 lladdr 00:18:51:34:bb:fd REACHABLE

[root at srv2 /]# ip route show
79.10.0.0/24 dev eth1  proto kernel  scope link  src 79.10.0.2
79.30.0.0/24 dev eth2  proto kernel  scope link  src 79.30.0.1
192.0.2.0/24 dev venet0  scope host
169.254.0.0/16 dev venet0  scope link
default via 192.0.2.1 dev venet0

[root at srv2 /]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/void
    inet 127.0.0.1/32 scope host venet0
5: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:18:51:61:b5:8d brd ff:ff:ff:ff:ff:ff
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:32:66:1c brd ff:ff:ff:ff:ff:ff
    inet 79.10.0.2/24 brd 79.10.0.255 scope global eth1
    inet6 fe80::218:51ff:fe32:661c/64 scope link
       valid_lft forever preferred_lft forever
9: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:3c:ed:33 brd ff:ff:ff:ff:ff:ff
    inet 79.30.0.1/24 brd 79.30.0.255 scope global eth2
    inet6 fe80::218:51ff:fe3c:ed33/64 scope link
       valid_lft forever preferred_lft forever
***************************************************************


And this is the output before the hello packets exchange stops:

-----------------------------------------------------------
[root at srv1 ipv4]# ip ru show
0:      from all lookup 255
32766:  from all lookup main
32767:  from all lookup default

[root at srv1 ipv4]# ip route show
79.10.0.0/24 dev eth1  proto kernel  scope link  src 79.10.0.1
79.0.0.0/24 dev eth0  proto kernel  scope link  src 79.0.0.1
79.30.0.0/24 via 79.10.0.2 dev eth1  proto xorp  metric 2 notify
192.0.2.0/24 dev venet0  scope host
169.254.0.0/16 dev venet0  scope link
default via 192.0.2.1 dev venet0

[root at srv1 ipv4]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/void
    inet 127.0.0.1/32 scope host venet0
    inet 192.168.1.101/32 brd 192.168.1.101 scope global venet0:0
5: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:69:63:aa brd ff:ff:ff:ff:ff:ff
    inet 79.0.0.1/24 brd 79.0.0.255 scope global eth0
    inet6 fe80::218:51ff:fe69:63aa/64 scope link
       valid_lft forever preferred_lft forever
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:34:bb:fd brd ff:ff:ff:ff:ff:ff
    inet 79.10.0.1/24 brd 79.10.0.255 scope global eth1
    inet6 fe80::218:51ff:fe34:bbfd/64 scope link
       valid_lft forever preferred_lft forever

[root at srv1 ipv4]# ip neigh show
79.10.0.2 dev eth1 lladdr 00:18:51:32:66:1c REACHABLE

-------------------------------------------------------

[root at srv2 /]# ip ru show
0:      from all lookup 255
32766:  from all lookup main
32767:  from all lookup default

[root at srv2 /]# ip route show
79.10.0.0/24 dev eth1  proto kernel  scope link  src 79.10.0.2
79.0.0.0/24 via 79.10.0.1 dev eth1  proto xorp  metric 2 notify
79.30.0.0/24 dev eth2  proto kernel  scope link  src 79.30.0.1
192.0.2.0/24 dev venet0  scope host
169.254.0.0/16 dev venet0  scope link
default via 192.0.2.1 dev venet0

[root at srv2 /]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/void
    inet 127.0.0.1/32 scope host venet0
5: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:18:51:61:b5:8d brd ff:ff:ff:ff:ff:ff
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:32:66:1c brd ff:ff:ff:ff:ff:ff
    inet 79.10.0.2/24 brd 79.10.0.255 scope global eth1
    inet6 fe80::218:51ff:fe32:661c/64 scope link
       valid_lft forever preferred_lft forever
9: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
    link/ether 00:18:51:3c:ed:33 brd ff:ff:ff:ff:ff:ff
    inet 79.30.0.1/24 brd 79.30.0.255 scope global eth2
    inet6 fe80::218:51ff:fe3c:ed33/64 scope link
       valid_lft forever preferred_lft forever

[root at srv2 /]# ip neigh show
79.10.0.1 dev eth1 lladdr 00:18:51:34:bb:fd REACHABLE



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