Configuring Topology Acquisition
Overview
After you have successfully established a connection between the NorthStar Controller and the network, you can configure topology acquisition using Border Gateway Protocol Link State (BGP-LS) or an IGP (OSPF or IS-IS). For BGP-LS topology acquisition, you must configure both the NorthStar Controller and the PCC routers.
We recommend that you use BGP-LS instead of IGP adjacency because:
The OSPF and IS-IS databases have lifetime timers. If the OSPF or IS-IS neighbor goes down, the corresponding database is not immediately removed, making it impossible for the NorthStar Controller to determine whether the topology is valid.
Using BGP-LS minimizes the risk of making the Junos VM a transit router between AS areas if the GRE metric is not properly configured.
Typically, the NorthStar Controller is located in a network operations center (NOC) data center, multihops away from the backbone and MPLS TE routers. This is easily accommodated by BGP-LS, but more difficult for IGP protocols because they would have to employ a tunneling mechanism such as GRE to establish adjacency.
If BGP-LS is used, the Junos VM is configured to automatically accept any I-BGP session. However, you must verify that the Junos VM is correctly configured and that it has IP reachability to the peering router.
Before You Begin
Before you begin, complete the following tasks:
Verify IP connectivity between a switch (or router) and the x86 appliance on which the NorthStar Controller software is installed.
Configure the Network Topology Acquisition Daemon (NTAD). The NTAD forwards topology information from the network to the NorthStar application, and it must be running on the Junos VM.
Use the following command to enable the NTAD:
junosVM# set protocols topology-export
Use the following command to verify that the NTAD is running; if the topology-export statement is missing, the match produces no results:
junosVM> show system processes extensive | match ntad 2462 root 1 96 0 6368K 1176K select 1:41 0.00% ntad
Configure BGP Monitoring Protocol (BMP) if you have decided to use BMP as an alternative to NTAD. BMP must be enabled on both the NorthStar and Junos VM sides.
Use a text editing tool such as vi to modify the /opt/northstar/data/northstar.cfg file, changing topology_src_protocol from 1 (which is NTAD) to 2 (which is BMP):
vi /opt/northstar/data/northstar.cfg . . . topology_src_protocol=2
Restart toposerver so the change takes effect:
supervisorctl restart northstar:toposerver
On the Junos VM, disable NTAD by deleting the protocols topology-export statement.
On the Junos VM, under “firewall”, configure the firewall filter to permit BMP TCP segments from NorthStar toward the Junos VM.
Note:Be sure to insert “term bmp” before “term default-discard”.
filter protect-re { term mgmt-intf { from { interface-set mgmt-intf; } then accept; } . . . term bmp { from { protocol tcp; port 10001; } then accept; } term default-discard { then { syslog; discard; } } }
On the Junos VM, under “routing options”, enable BMP:
bmp { connection-mode active; monitor enable; station northstar { station-address station-address; station-port 10001; } } } Where, station-address is any IP address of the controller that can be accessed externally. If the JunosVM and the controller are present on the same network segment, the station-address must be in the shared network segment.
Configuring Topology Acquisition Using BGP-LS
- Configure BGP-LS Topology Acquisition on the NorthStar Controller
- Configure the Peering Router to Support Topology Acquisition
Configure BGP-LS Topology Acquisition on the NorthStar Controller
To configure BGP-LS topology acquisition on the NorthStar Controller, perform the following configuration steps from the NorthStar Junos VM:
Configure the Peering Router to Support Topology Acquisition
To enable the NorthStar Controller to discover the network, you must add the following configuration on each router that peers with the NorthStar Controller. The NorthStar Junos VM must peer with at least one router from each area (autonomous system).
To enable topology acquisition, initiate a telnet session to each PCC router and add the following configuration:
Configuring Topology Acquisition Using OSPF
Configure OSPF on the NorthStar Controller
To configure OSPF on the NorthStar Controller:
Configure OSPF over GRE on the NorthStar Controller
Once you have configured OSPF on the NorthStar Controller, you can take the following additional steps to configure OSPF over GRE:
Configuring Topology Acquisition Using IS-IS
Configure IS-IS on the NorthStar Controller
To configure IS-IS topology acquisition and enable IS-IS routing, perform the following steps on the NorthStar Junos VM:
Configure IS-IS over GRE on the NorthStar Controller
Once you have configured IS-IS on the NorthStar Controller, you can take the following additional steps to configure IS-IS over GRE: