VXLAN Layer 2 gateway considerations and limitations
Note the following considerations and limitations for VXLAN Layer 2 gateway.
- A maximum of 512 tunnels are
supported.
- A maximum of 8 ECMP paths are
supported.
- Layer 2 snooping is not supported.
- VRRPe source IP addresses and Multi-Chassis Trunks
(MCTs) are not supported.
- QoS, TTL, and MTU values are not
configurable. The MTU is based on the IP interface MTU. If a packet is bigger
than the IP interface MTU minus the VXLAN header, the packet is dropped. The
default TTL value is 255. The default QoS value is 0, which is applied to the
DSCP field of the IP header.
- VXLAN tunnels have the standard UDP
header encapsulated with the standard defined value of 4789. This value is not
configurable. SLX-OS expects VXLAN tunnel packets to be received with this
value.
- VXLAN tunnels are supported in the
default profile.
- VXLAN tunnels are not supported when the counter
profile 1 or 4 is configured. These profiles do not allocate hardware resources
for TX statistics, which is needed for VXLAN tunnels. (SLX 9540 and SLX 9640
only).
- Static VXLAN Tunnels are not supported on the SLX 9150 and SLX 9250.
- The tunnel TX bytes statistics do not
account for the outer VLAN header size.
- When BUM packets received on a tunnel
are flooded, split horizon drops the packets to the same tunnel. However, the TX
Statistics counter on that tunnel increments.
VNI Mapping
VLAN-VNI mapping is shared by all VxLAN tunnels including the ICL. There are three
methods of configuring VNI mapping.
- Auto-Mapping
- This is the default configuration, and is recommended for use with the
cluster. The first 32K are reserved for the VNI range. A one-to-one
mapping between the VLAN/BD and the VNI is configured.
- Manual Mapping for a specific VLAN/BD (hybrid mode)
- With map vni auto configured, a specific VLAN/BD can
be manually mapped. The manual mapping VNI range starts at 32768. Other
VLANs/BDs will continue to use auto mapping.
- Manual mapping of all VLANs/BDs (disable auto mapping)
- When auto mapping is disabled, manual VNI mapping is required for all
VLANs/BDs created on the system (even the VLANs/BDs that are not
configured under EVPN). In this mode, the complete VNI range (1-2^24) is
available for manual mapping.
![Note](images/note.png)
Note
- When the VNI mapping is changed, traffic on the ICL is
impacted.
- The VNI Mapping on the two nodes must match.