Bidirectional Forwarding Detection quickly notices when a forwarding path breaks, letting an NSX Tier-0 gateway fail over its BGP sessions or static routes without waiting for hold timers to expire. Most VCF edge designs keep standard BGP timers alongside it; the exception is the dual-zone vSphere HA recovery design, which omits BFD, as vMotion can disrupt sessions, and shortens the timers instead.
Also called Bidirectional Forwarding Detection.
Read more: Broadcom TechDocs
In the Ultra Transcenders books
Each book explains BFD in context, with comparison tables and the common traps.
Terms in this definition
- BFD
Protocol that spots a failed ExpressRoute link in less than a second. Microsoft's MSEE routers already have it on for new peerings, so you enable it on your own edge routers and tie it to the BGP session.
- PATH
Parent-child hierarchies in DAX rely on this function. For each row it builds one delimited text value listing the IDs of the row's ancestors, top level first and ending with the row's own ID, which PATHITEM, PATHLENGTH and friends can then pick apart.
- NSX
Software that handles networking and security across VCF, covering firewalling, load balancing, NAT, VPCs, overlay segments and Tier-0/1 gateways.
- Tier-0 gateway
Gateway that ties NSX's virtual networks to the physical network for north-south traffic. Besides distributed routing it has a service router on Edge nodes for centralised routing and services; each Edge node can only host one.
- OVER
Gives a T-SQL window function its window: PARTITION BY, ORDER BY and, if wanted, a ROWS or RANGE frame. Rankings and running totals can then be worked out while every row is kept.
- BGP
Dynamic routing protocol used with both ExpressRoute and VPN connections. On ExpressRoute private peering it is the only way to exchange routes, including a 0.0.0.0/0 default route for forced tunnelling.
- VCF Edge
VCF tailored to remote locations such as branches and shops, built on Broadcom's documented edge patterns. It calls for ten or more locations, hosts of eight cores or more, a 256-core ceiling per location, and edge hardware kept physically away from workloads in the data centre.
- Standard deployment type
A Foundry deployment type billed per token that keeps processing of prompts and responses inside the Azure geography of the resource, meeting data residency needs at lower volumes.