Contrail typically consists of a cluster of nodes. The three main nodes are the config, control and compute. The config node is where the Openstack Horizon and Contrail Controller exists. The Control node is used to form a MP-BGP session to a gateway router. The Compute node hosts all the VMs and virtual networks.
You can think of Contrail as a PE router as pretty much this is what a gateway router perceives the other end of the connection. Contrail uses a vRouter and when you configure virtual networks you have the ability to add a route-target to that virtual network. On the Gateway router you would create VRFs to associate with the corresponding virtual networks and prefixes can be exchanged. Data plane traffic will traverse through an MPLS tunnel between Contrail and the Gateway router. It's at the gateway router where you would "leak" the received Contrail virtual network into the main routing instance of the gateway router.
Here I use an Juniper MX as the gateway router. When I first setup contrail I used the testbed.py script to add the mx gateway router.
It's called ext_router = [ip address]
Then in contrail webui I should see the BGP session. You can however add this post contrail installation.
On the MX, I configure an iBGP session to connect with the Contrail control node.
user@router# show protocols
mpls {
interface all;
}
bgp {
group IBGP-CONTRAIL {
type internal;
local-address 192.168.10.11;
family inet-vpn {
unicast;
}
neighbor 192.168.10.2;
}
}
Then in Contrail config node I create a virtual network and add a route target.
I create a corresponding VRF on the MX with the route target.
user@router# show routing-instances
VRF1 {
instance-type vrf;
interface lt-3/0/0.3;
route-distinguisher 1.1.1.1:101;
vrf-target
target:64512:101;
routing-options {
static {
route 0.0.0.0/0 next-hop 192.168.12.1;
}
}
}
I check to see the BGP session established.
user@router# run show bgp summary
Groups: 1 Peers: 1 Down peers: 0
Table Tot Paths Act Paths Suppressed History Damp State Pending
bgp.l3vpn.0
8 8 0 0 0 0
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
192.168.10.2 64512 5724 6292 0 3 1d 23:08:56 Establ
bgp.l3vpn.0: 8/8/8/0
VRF1.inet.0: 3/3/3/0
The Virtual Network IP addresses for the VMs will be sent.
user@router# run show route receive-protocol bgp 192.168.10.2
VRF1.inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 11.1.1.1/32 192.168.10.3 100 ?
* 11.1.1.5/32 192.168.10.3 100 ?
* 11.1.1.7/32 192.168.10.3 200 ?
bgp.l3vpn.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
192.168.10.3:7:11.1.1.1/32
* 192.168.10.3 100 ?
192.168.10.3:7:11.1.1.5/32
* 192.168.10.3 100 ?
192.168.10.3:7:11.1.1.7/32
* 192.168.10.3 200 ?
mpls.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
0 *[MPLS/0] 1w1d 04:10:08, metric 1
Receive
1 *[MPLS/0] 1w1d 04:10:08, metric 1
Receive
2 *[MPLS/0] 1w1d 04:10:08, metric 1
Receive
13 *[MPLS/0] 1w1d 04:10:08, metric 1
Receive
299904 *[VPN/170] 1d 23:14:00
> to 192.168.11.1 via lt-3/0/0.1, Pop
299936 *[VPN/170] 1d 12:47:38
receive table VRF1.inet.0, Pop
299952 *[VPN/170] 1d 12:47:38
> to 192.168.12.1 via lt-3/0/0.3, Pop
bgp.l3vpn.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
192.168.10.3:7:11.1.1.1/32
*[BGP/170] 1d 12:46:01, localpref 100, from 192.168.10.2
AS path: ?, validation-state: unverified
> via
gr-3/0/0.32770, Push 24
192.168.10.3:7:11.1.1.5/32
*[BGP/170] 1d 12:46:01, localpref 100, from 192.168.10.2
AS path: ?, validation-state: unverified
> via
gr-3/0/0.32770, Push 18
192.168.10.3:7:11.1.1.7/32
*[BGP/170] 1d 12:26:14, localpref 200, from 192.168.10.2
AS path: ?, validation-state: unverified
> via
gr-3/0/0.32770, Push 28
Note the dynamic MPLS GRE tunnel is created. You will need to create one on the MX.
user@router# show chassis
fpc 3 {
pic 0 {
tunnel-services;
}
}
user@router# show routing-options
static {
route 0.0.0.0/0 next-hop 10.161.1.1;
}
autonomous-system 64512;
dynamic-tunnels {
dynamic_overlay_tunnels {
source-address 192.168.10.11;
gre;
destination-networks {
192.168.10.0/24;
}
}
}
PoC-Demo.inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
0.0.0.0/0 *[Static/5] 1d 13:05:36
> to 192.168.12.1 via lt-3/0/0.3
11.1.1.1/32 *[BGP/170] 1d 13:03:59, localpref 100, from 192.168.10.2
AS path: ?, validation-state: unverified
> via gr-3/0/0.32770, Push 24
11.1.1.5/32 *[BGP/170] 1d 13:03:59, localpref 100, from 192.168.10.2
AS path: ?, validation-state: unverified
> via gr-3/0/0.32770, Push 18
11.1.1.7/32 *[BGP/170] 1d 12:44:12, localpref 200, from 192.168.10.2
AS path: ?, validation-state: unverified
> via gr-3/0/0.32770, Push 28
192.168.12.0/24 *[Direct/0] 1d 13:05:36
> via lt-3/0/0.3
192.168.12.2/32 *[Local/0] 1d 13:05:36
Local via lt-3/0/0.3
LT interfaces are created to allow the virtual network traffic to communicate between the VRF and the main routing instance. You could also use RIB groups and Policies to do the same thing.
lt-3/0/0 {
unit 2 {
encapsulation ethernet;
peer-unit 3;
family inet {
address 192.168.12.1/24;
}
}
unit 3 {
encapsulation ethernet;
peer-unit 2;
family inet {
address 192.168.12.2/24;
}
}
}
You then need to make sure the interface that is connecting to the Contrail network is using MPLS.
interfaces {
ge-3/1/1 {
unit 0 {
family inet {
address 192.168.10.11/24;
}
family mpls;
}
}
lo0 {
unit 0 {
family inet {
address 1.1.1.1/32;
}
family iso {
address 49.0002.0010.0100.1001.00;
}
}
}
}
One thing you should be aware of is the next-hop of the route advertised by contrail points to the IP address of the Compute Node and not the control node.
user@router# run show route 11.1.1.1/32 detail
VRF1.inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
11.1.1.1/32 (1 entry, 1 announced)
*BGP Preference: 170/-101
Route Distinguisher: 192.168.10.3:7 <<< Contrail's RD
Next hop type: Indirect
Address: 0x94f4a28
Next-hop reference count: 3
Source: 192.168.10.2
Next hop type: Router, Next hop index: 660
Next hop: via gr-3/0/0.32770, selected
Label operation: Push 24
Label TTL action: prop-ttl
Session Id: 0xd
Protocol next hop:
192.168.10.3 <<<< IP of compute node
Push 24
Indirect next hop: 0x9574410 1048574 INH Session ID: 0xe
State: <Secondary Active Int Ext ProtectionCand>
Local AS: 64512 Peer AS: 64512
Age: 1d 13:54:24 Metric2: 0
Validation State: unverified
Task: BGP_64512.192.168.10.2+34735
Announcement bits (1): 1-KRT
AS path: ?
Communities:
target:64512:101 << RT from contrail
Import Accepted
VPN Label: 24
Localpref: 100
Router ID:
192.168.10.2 <<<< IP of control node
Primary Routing Table bgp.l3vpn.0
