#OSPF NETWORK TYPES HOW TO#

The active Tier-0 SR advertises its prefixes with a cost of 20 and a type of “E2” while the standby Tier-0 service router advertises the same prefixes with a cost of 65534. The traffic destined for the Tier-0 DR must be sent from the top of rack switch to the active Tier-0 gateway. In the active/standby topology represented in Figure 9, the Tier-0 gateway running in standby mode is running the OSPF process and establishes an adjacency with the top of rack switchesĪs mentioned previously, the routes redistributed into the OSPF process are advertised as E2 (or N2). Stateful services can be used on a Tier-0 service router when high availability status is running in active/standby mode.īoth the OSPF point to point and broadcast network types are available in either active/standby or active/active high availability Tier-0 topologies. OSPF is supported on both active/standby and active/active topologies. Table 2 – BFD Timers support within NSX-T Edge Node Form Factor Table 2 states the different values supported by the edge node on both bare metal and virtual machine form factors. Since NSX-T 3.0, the BFD timers have been improved to provide best-in-class neighbor failure detection time. To provide a faster detection time, NSX-T supports BFD which will trigger OSPF, bringing down the adjacency in case of a top of rack switch failure. Table 1 – OSPF d efault timers OSPF Timers According to these OSPF timers, it will take up to 40 seconds to detect the failure of a neighbor. Table 1 represents the default timers used in OSPF for both the point-to-point and broadcast OSPF interface type. The “2 way” adjacencies on Tier-0 are represented in red on Figures 7 and 8.įigure 8 – OSPF adjacencies in “Full” and “2-Way” state in the OSPF broadcast network type OSPF Supported Topologies OSPF Adjacencies From an OSPF perspective, the Tier-0 service router’s type is considered “DROther”. The Tier-0 service router hosted on Edge Node 01 will be able to see the OSPF Hello packets sent on vlan 101 and vlan 102 by the Tier-0 service router hosted on the Edge Node 02, but their adjacency state will stay in the “2 way” state and they will not exchange their LSDatabase. OSPF routers on the segment will fully establish an adjacency with the DR and BDR only.Īs demonstrated in Figure 7, the Tier-0 service routers hosted on both Edge Node 01 and Edge Node 02 will fully establish an adjacency with both ToR-01 (DR) and ToR-02 (BDR) (represented as the green adjacencies in Figures 7 and 8). On a multi-access segment (Broadcast OSPF network type), OSPF elects a designated router (DR) and a backup designated router (BDR) to reduce the number of adjacencies. Figure 1 demonstrates that the protocol can be enabled on external interfaces hosted on Tier-0 gateways.įigure 6 – OSPF Adjacencies in “Full” state in OSPF P2P network type OSPF Broadcast Network Type OSPF v2 is supported on NSX-T starting with NSX-T 3.1.1. With the topology mapped, each OSPF routers compute the shortest path to each destination using the Dijkstra algorithm. This information is then shared among all the routers in the area and stored in a link state database (LSDb). Routers using a link state dynamic routing protocol like OSPF exchange a complete topology of the network (state of each link) with their direct neighbors.

The main purpose of any routing protocol is to dynamically exchange or share information regarding the reachability of a network. Providing connectivity between users and applications in a data center is crucial.

#OSPF NETWORK TYPES HOW TO#

In this blogpost, we will demonstrate how to implement OSPFv2 within NSX-T in your data center. By supporting OSPF as a dynamic routing protocol, existing NSX for vSphere customers can migrate seamlessly to NSX-T. OSPF is now an option to consider leveraging dynamic routing protocols in the data center. Interconnecting your physical networking fabric with NSX-T was possible using static routes and BGP. As a result, it is one of the most popular link state routing protocols in enterprise networks and data centers. NSX-T version 3.1.1 will go down as a critical milestone in this journey, as it supports OSPF version 2.īased on RFC 2328, Open Shortest Path First Version 2 (OSPF v2) provides fast convergence, scalability, and is widely known among network architects and their operations teams. Its unmatched capabilities are key elements in any effort to modernize networking in the data center. NSX-T has revolutionized the data center and plays a key role in modern data center fabrics.

Ospf network types