The router that traffic reaches first on leaving a VLAN segment. VCF needs the data centre to supply one, with an appropriate MTU, for each infrastructure VLAN, and advises using a VRRP or HSRP virtual address that stays available through any failure the cluster model is designed to withstand.
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Terms in this definition
- FIRST
A DAX function available only inside visual calculations. It fetches the value at the start of one axis of the visual's matrix, which makes it handy for comparing each point with the first; its opposite is LAST.
- VLAN
Layer 2 broadcast domain tagged using 802.1Q. In VCF they carry TEP, vSAN, vMotion and management traffic, and NSX can back segments with them.
- segment
A layer 2 network in NSX for VM connections. Overlay-backed ones carry traffic in tunnels between TEPs; VLAN-backed ones correspond to a physical VLAN.
- VMware Cloud Foundation
Broadcom's platform for private cloud. It unifies management of NSX, vSAN, vSphere, VCF Automation and VCF Operations as one fleet; VVF, by contrast, lacks automation and cloud management.
- MTU
Biggest frame an interface can carry. The physical fabric needs at least 1600 bytes for NSX overlay traffic, with 1700 recommended and 9000 preferred where jumbo frames run end to end.
- VRRP
A protocol giving LAN gateways redundancy; Azure VNets don't use it for routing.
- HSRP
The Hot Standby Router Protocol provides redundant gateways on a LAN; Azure routing does not use it.
Related terms
- HSRP
For each infrastructure VLAN, VCF recommends a highly available first-hop gateway in the form of a floating address provided by HSRP or VRRP. HSRP itself is a first-hop redundancy protocol in which several switches share that floating gateway address.
- Network fabric model
Matched to the vSphere cluster model, this VCF design model fixes the MTU, first-hop gateway availability and VLAN scope for each traffic type on the physical data centre fabric. Its options are Single-Rack; Multi-Rack, either Layer 2 or Layer 3 (not for the management domain's first cluster); and Multi Availability Zone for stretched clusters.
- ToR
Top-of-rack, describing the switch at the top of each rack to which its hosts are cabled. Each ESX host in VCF needs a link to one switch as a minimum, though two or more are advised; their first-hop gateway must then run on every switch or move between them on failure.