[ovs-discuss] Two GRE tunnels with same src/dst

Frank frank at cloud.com
Thu Jan 13 22:22:58 UTC 2011


On 01/04/2011 02:34 PM, Jesse Gross wrote:
> On Thu, Dec 30, 2010 at 6:00 PM, Frank<frank at cloud.com>  wrote:
>> Hi guys:
>>     I just try to create two GRE tunnels between two hosts, the result is I
>> can't do this.
>>     vswitch complains "could not create iface test: File exists" when
>> creating second tunnel.
>>     I did set different GRE keys for tunnels.
>>
>>     I google and get some articles said it's possible to create multiple GRE
>> tunnels with same src/dst.
>>     I am curious what technical barrier prevents our doing since GRE key is
>> an natural tag to distinguish different tunnels.
> You can have multiple tunnels between the same endpoints if they are
> distinguished by key.  Please post your interface config.
>

I am sorry for late reply. I create tunnels as below (ovs is alias of 
ovs-vsctl):

[root at xenserver-frank4 ~]# ovs list interface 1-2
_uuid               : ebc0d114-d258-4670-9965-8a5a0491b0b9
external_ids        : {}
ingress_policing_burst: 0
ingress_policing_rate: 0
mac                 : []
name                : "1-2"
ofport              : 8
options             : {remote_ip="192.168.152.22 key=1"}
statistics          : {collisions=0, rx_bytes=894703, rx_crc_err=0, 
rx_dropped=0, rx_errors=0, rx_frame_err=0, rx_over_err=0, 
rx_packets=12083, tx_bytes=28882506, tx_dropped=0, tx_errors=0, 
tx_packets=21760}
status              : {}
type                : gre
[root at xenserver-frank4 ~]# ovs create interface name=test 
options:"remote_ip=192.168.152.22 key=2"
74c1e2e3-da43-4ae4-86e7-048de205f974

[root at xenserver-frank4 ~]# ovs create port name=test 
interfaces=[74c1e2e3-da43-4ae4-86e7-048de205f974]
3dc08a5c-102c-45c6-9891-9692d2d4a8e3

[root at xenserver-frank4 ~]# ovs add bridge xapi7 ports 
3dc08a5c-102c-45c6-9891-9692d2d4a8e3

[root at xenserver-frank4 ~]# ovs list interface test
_uuid               : 74c1e2e3-da43-4ae4-86e7-048de205f974
external_ids        : {}
ingress_policing_burst: 0
ingress_policing_rate: 0
mac                 : []
name                : test
ofport              : []
options             : {remote_ip="192.168.152.22 key=2"}
statistics          : {}
status              : {}
type                : ""


Actually I already had a tunnel to "192.168.152.22" with key = 1. we can 
see the secondary creation was failed even I set the key=2.
In ovs-vswitchd.log, here are:

Jan 13 14:18:31|02259|netdev|WARN|failed to get flags for network device 
test: No such device
Jan 13 14:18:31|02260|bridge|WARN|could not create iface test: No such 
device
Jan 13 14:18:31|02261|bridge|WARN|bridge xapi7: port test has no 
interfaces, dropping







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