Connectivity Guide

Congure the same VLTi VLAN ID on both VLT peers. You cannot use the ID of an existing VLAN on a VLT peer or the reserved
untagged VLAN ID. You can use the VLTi VLAN ID to assign tagged or untagged access interfaces to a virtual network.
virtual-network vn-id
vlti-vlan vlan-id
• Although a VXLAN virtual network has no access port members that connect to downstream servers, you must congure a switch-
scoped VLAN or VLTi VLAN. The presence of this VLAN ensures that the VLTi link is added as a member of the virtual network so that
mis-hashed ARP packets received from the VXLAN tunnel reach the intended VLT node.
Best practices:
• If a VLT peer loses connectivity to the underlay L3 network, it continues to transmit routing trac to the network through the VLTi link
on a dedicated L3 VLAN to the other VLT peer. Congure a L3 VLAN between VLT peers in the underlay network and enable routing on
the VLAN; for example:
OS10(config)# interface vlan4000
OS10(config-if-vl-4000)# no shutdown
OS10(config-if-vl-4000)# ip address 41.1.1.1/24
OS10(config-if-vl-4000)# ip ospf 1 area 0.0.0.0
• To reduce trac loss when a VLT peer boots up and joins an existing VLT domain, or when the VLTi links fails and the VLT peer is still up
as detected by the VLT heartbeat, create an uplink state group. Congure all access VLT port channels on the peer as upstream links.
Congure all network-facing links as downstream link. For example:
OS10(config)# uplink-state-group 1
OS10(conf-uplink-state-group-1)# enable
OS10(conf-uplink-state-group-1)# downstream ethernet1/1/1-1/1/2
OS10(conf-uplink-state-group-1)# upstream port-channel 10
L3 VXLAN route scaling
The S4100-ON series, S5200-ON series, S4048T-ON, and S6010-ON switches support native VxLAN routing — routing in and out of
tunnels (RIOT). RIOT requires dedicated hardware resources reserved for overlay routing. You cannot use these dedicated resources for
underlay routing.
Each overlay ARP entry requires a routing next-hop in the hardware to bind a destination tenant VM IP address to the corresponding
tenant VM MAC address and VNI. Each virtual-network interface assigned to an IP subnet requires a routing interface in the hardware.
OS10 supports preset proles to re-allocate the number of resources reserved for overlay ARP entries. The number of entries reserved for
each preset mode diers according to OS10 switch.
Table 22. Routing next-hops reserved on OS10 switches
OS10 Switch Overlay next-
hop entries
Underlay next-
hop entries
Overlay L3 RIF
entries
Underlay L3 RIF entries
S41xx-ON series:
default-overlay-routing
disable-overlay-routing
balanced-overlay-routing
scaled-overlay-routing
—
4096
0
16384
24576
—
28672
32768
16384
8192
—
2048
0
6144
10240
—
10240
12288
6144
2048
S4048T-ON and S6010-ON:
default-overlay-routing
disable-overlay-routing
balanced-overlay-routing
—
8192
0
24576
—
4096
49152
24576
—
2048
49152
24576
—
2048
0
6144
VXLAN 687