Configuring OSPF on an edge services gateway (ESG) enables the ESG to learn and advertise routes. The most common application of OSPF on an ESG is on the link between the ESG and a Logical (Distributed) Router. This allows the ESG to learn about the logical interfaces (LIFS) that are connected to the logical router. This goal can be accomplished with OSPF, IS-IS, BGP or static routing.
OSPF routing policies provide a dynamic process of traffic load balancing between routes of equal cost.
An OSPF network is divided into routing areas to optimize traffic flow and limit the size of routing tables. An area is a logical collection of OSPF networks, routers, and links that have the same area identification.
Areas are identified by an Area ID.
A Router ID must be configured, as shown in OSPF Configured on the Edge Services Gateway.
When you enable a router ID, the field is populated by default with the ESG's uplink interface IP address.
- Log in to the vSphere Web Client.
- Click Networking & Security and then click NSX Edges.
- Double-click an ESG.
- Click Routing and then click OSPF.
- Enable OSPF.
- Click Edit at the top right corner of the window and click Enable OSPF
- (Optional) Click Enable Graceful Restart for packet forwarding to be un-interrupted during restart of OSPF services.
- (Optional) Click Enable Default Originate to allow the ESG to advertise itself as a default gateway to its peers.
- Configure the OSPF areas.
- (Optional) Delete the not-so-stubby area (NSSA) 51 that is configured by default.
- In Area Definitions, click the Add icon.
- Type an Area ID. NSX Edge supports an area ID in the form of an IP address or decimal number.
- In Type, select Normal or NSSA.
NSSAs prevent the flooding of AS-external link-state advertisements (LSAs) into NSSAs. They rely on default routing to external destinations. Hence, NSSAs must be placed at the edge of an OSPF routing domain. NSSA can import external routes into the OSPF routing domain, thereby providing transit service to small routing domains that are not part of the OSPF routing domain.
- (Optional) Select the type of Authentication. OSPF performs authentication at the area level.
All routers within the area must have the same authentication and corresponding password configured. For MD5 authentication to work, both the receiving and transmitting routers must have the same MD5 key.
- None: No authentication is required, which is the default value.
- Password: In this method of authentication, a password is included in the transmitted packet.
- MD5: This authentication method uses MD5 (Message Digest type 5 ) encryption. An MD5 checksum is included in the transmitted packet.
- For Password or MD5 type authentication, type the password or MD5 key.
- Map interfaces to the areas.
- In Area to Interface Mapping, click the Add icon to map the interface that belongs to the OSPF area.
- Select the interface that you want to map and the OSPF area that you want to map it to.
- (Optional) Edit the default OSPF settings.
In most cases, it is recommended to retain the default OSPF settings. If you do change the settings, make sure that the OSPF peers use the same settings.
Hello Interval displays the default interval between hello packets that are sent on the interface.
Dead Interval displays the default interval during which at least one hello packet must be received from a neighbor before the router declares that neighbor down.
Priority displays the default priority of the interface. The interface with the highest priority is the designated router.
Cost of an interface displays the default overhead required to send packets across that interface. The cost of an interface is inversely proportional to the bandwidth of that interface. The larger the bandwidth, the smaller the cost.
- Click Publish Changes.
- Make sure that the route redistribution and firewall configuration allow the correct routes to be advertised.
OSPF Configured on the Edge Services Gateway
One simple NSX scenario that uses OSPF is when a logical router and an edge services gateway are OSPF neighbors, as shown here.
The ESG can be connected to the outside world through a bridge, a physical router (or as shown here) through an uplink portgroup on a vSphere distributed switch.
In the following screen, the ESG's default gateway is the ESG's uplink interface to its external peer.
The router ID is the ESG's uplink interface IP address---in other words, the IP address that faces its external peer.
The area ID configured is 0, and the internal interface (the interface facing the logical router) is mapped to the area.
The connected routes are redistributed into OSPF so that the OSPF neighbor (the logical router) can learn about the ESG's uplink network.
Additionally, OSPF can be configured between the ESG and its external peer router, but more typically this link uses BGP for route advertisement.
Make sure that the ESG is learning OSPF external routes from the logical router.
To verify connectivity, make sure that an external device in the physical architecture can ping the VMs.
PS C:\Users\Administrator> ping 172.16.10.10 Pinging 172.16.10.10 with 32 bytes of data: Reply from 172.16.10.10: bytes=32 time=5ms TTL=61 Reply from 172.16.10.10: bytes=32 time=1ms TTL=61 Ping statistics for 172.16.10.10: Packets: Sent = 2, Received = 2, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 5ms, Average = 3ms
PS C:\Users\Administrator> ping 172.16.20.10 Pinging 172.16.20.10 with 32 bytes of data: Reply from 172.16.20.10: bytes=32 time=2ms TTL=61 Reply from 172.16.20.10: bytes=32 time=1ms TTL=61 Ping statistics for 172.16.20.10: Packets: Sent = 2, Received = 2, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 2ms, Average = 1ms