Core Config Options:
First Hop/Gateway Redundancy:
VRRP:
- Same Switch hosts VRRP and STP Master-ship for deterministic forwarding @ L2/L3 and eliminate suboptimal forwarding path.
- In a non-VLT domain, only the Master owns VIP and actively forwards @ Layer 3, but in a VLT domain, both Master & backup actively forward traffic in the ”enhanced” VRRP.
- Can scale to a maximum of 255 VLANs
Peer-Routing:
- within a VLT domain, each peer forwards routed traffic on behalf of the other, regardless of whether the gateway is hosted on other switch.
- No VIP Configured. Either peer’s physical IP on the VLAN can be assigned as host gateway – regardless, both peers will forward traffic for own as well as Peer VLAN SVI (Proxy gateway).
- Achieved by having the destination MAC of the respective VLAN SVI, exist in each peer’s L2 CAM as Local DA.
- Will scale to the limit of configurable number of VLANs.
- Enabled globally via a single command, unlike VRRP (Per VLAN)
Routed VLT:
- OSPF/Dynamic RP can be run within the VLT domain, L3 adjacencies can be formed over VLTi between peer switches. Unique to Dell Networking MLAG implementation.
L2/L3 Boundary
- Core VLT Peers host Layer 3 gateways for the VLANs/network.
- ToR VLT Peers are Layer2 only, extending L2 domains from the Core down to the Edge.
- Uplinks between Core and Internet Edge/Firewall will be configured as L3, and managed by static/dynamic RP.
Hasan Mansur 