- Published on
NSX-T Routing
- Authors
- Name
- Jackson Chen
NSX-T T0 Active-Active Gateway and BGP Peering
NSX-T supports BGP as the only dynamic routing protocol to peer the Edges (T0 Gateways) with the customer network. BGP is supported only on the Tier 0 gateways unlike NSX-V which supports dynamic routing on both the DLR and ESGs. Peering of T1 and T0 Gateways are fully managed by NSX-T and is transparent to the administrators. T1 and T0 Gateways attach to each other using NSX-T router links (on a pre-defined 100.64.0.0 subnet) which is fully managed by NSX-T manager. When we enable Route advertisement on the T1 Gateway, NSX-T manager automatically establishes static routing between the T1 & T0 Gateways for the advertised routes. These routes are named as NSX Static routes in the UI.
Tier0 Inter-SR Routing
Inter-SR Routing is an iBGP peering feature between the SR Components of the Tier 0 Gateway deployed in Active-Active mode. This feature helps to tolerate an asymmetric failure of the SR component on the Edge node by routing the internal traffic reaching to it over the iBGP inter-SR link to the SR component on the other Edge node for northbound reachability.
https://vxplanet.com/2019/07/12/nsx-t-tier0-inter-sr-routing-explained/
NSX-T Tier0 Inter-SR iBGP ECMP Explained
NSX-T introduced Inter-SR iBGP routing between the SR Components of the T0 Gateway in version 2.4. This feature helps to tolerate an asymmetric failure of the SR component on the Edge node (Eg: uplink failures) by routing the internal traffic reaching to it (from the T0 DR Component) over to the iBGP inter-SR link to the SR component on the other Edge nodes for northbound reachability. This feature is available only when the Tier0 Gateway is deployed in Active-Active mode and that with ECMP enabled under the BGP process.
ECMP is achieved on the Inter-SR routing link, so that in the event of uplink failures on one T0 SR Component, traffic is load shared to all the other T0 SR components avoiding a possible bottleneck.
https://vxplanet.com/2019/08/22/nsx-t-tier0-inter-sr-ibgp-ecmp-explained/
Routing Topologies
Single Tier
In a single tier topology, only T0 gateway is deployed. Segments are connected directly to T0 gateway.
Multitier
In a multier topology, T0 and T1 gateway are included. Cloud management platforms (CMP) are typically provision T1 gateways.
Edge Transport Node
The edge transport nodes provide the following functions:
a. Connectivity to the external networks
b. Host centralized services, such as NAT and Load Balancer
c. Must join an edge cluster
d. Edge cluster provide redundancy and scalability
Gateway Services
## T0 Gateway services
# T0 Gateway active-standby supported services
NAT, Load Balancing, Stateful Firewall, and VPN