Connectivity Guide

ManualsBrandsDell ManualsAccess PlatformsPowerSwitch S4048-ON

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Conguration notes for virtual-network routing:

• VXLAN overlay routing includes routing tenant trac on the ingress VTEP and bridging the trac on the egress VTEP. The ingress

VTEP learns ARP entries and associates all destination IP addresses of tenant VMs with the corresponding VM MAC addresses in the

overlay. On the ingress VTEP, congure a virtual network for each destination IP subnet even if there are no locally attached hosts for

an IP subnet.

• Routing protocols, such as Open Shortest Path First (OSPF) and BGP, are not supported on the virtual-network interface in the overlay

network. However, static routes that point to a virtual-network interface or to a next-hop IP address that belongs to a virtual-network

subnet are supported.

• When you add a static route in the overlay, any next-hop IP address that belongs to a virtual-network subnet must be the only next-hop

for that route and cannot be one of multiple Electronic Commerce Messaging Protocol (ECMP) next-hops. For example, if you enter

the following conguration commands one after the other, where 10.250.0.0/16 is a virtual-network subnet, only the rst next-hop

is active on the switch.

OS10(config)# ip route 0.0.0.0/0 10.250.0.101

OS10(config)# ip route 0.0.0.0/0 10.250.0.102

If the next-hop is a pair of dual-homed VTEPs in a VLT domain, a workaround is to congure the same anycast gateway IP address on

both VTEPs and use this address as the next-hop IP address.

• VLT peer routing is not supported in a virtual network. A packet destined to the virtual-network peer MAC address L2 switches instead

of IP routes. To achieve active-active peer routing in a virtual network, congure the same virtual anycast gateway IP and MAC

addresses on both VTEP VLT peers and use the anycast IP as the default gateway on the VMs.

• Virtual Router Redundancy Protocol (VRRP) is not supported on a virtual-network interface. Congure the virtual anycast gateway IP

address to share a single gateway IP address on both VTEP VLT peers and use the anycast IP as default gateway on the VMs.

• Internet Group Management Protocol (IGMP) and Protocol-Independent Multicast (PIM) are not supported on a virtual-network

interface.

• IP routing of incoming VXLAN encapsulated trac in the overlay after VXLAN termination is not supported.

The following tables show how to use anycast gateway IP and MAC addresses in a data center with three virtual networks and multiple

VTEPs:

• Globally congure an anycast MAC address for all VTEPs in all virtual networks. For example, if you use three VTEP switches in three

virtual networks:

Table 20. MAC address for all VTEPs

Virtual network VTEP Anycast gateway MAC address

VNID 11 VTEP 1

VTEP 2

VTEP 3

00.11.22.33.44.55

VNID 12 VTEP 1

VTEP 2

VTEP 3

00.11.22.33.44.55

VNID 13 VTEP 1

VTEP 2

VTEP 3

00.11.22.33.44.55

• Congure a unique IP address on the virtual-network interface on each VTEP across all virtual networks. Congure the same anycast

gateway IP address on all VTEPs in a virtual-network subnet. For example:

VXLAN

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