|
Feature |
Product |
Release introduced |
|---|---|---|
|
Fabric Extend Tunnel IS-IS MTU configuration |
5320 Series |
Planned for Fabric Engine 8.10.1 |
|
5420 Series |
Planned for Fabric Engine 8.10.1 |
|
|
5520 Series |
Planned for Fabric Engine 8.10.1 |
|
|
5720 Series |
Planned for Fabric Engine 8.10.1 |
|
|
7520 Series |
Planned for Fabric Engine 8.10.1 |
|
|
7720 Series |
Planned for Fabric Engine 8.10.1 |
|
|
VSP 4450 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 4900 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 7200 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 7400 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 8200 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 8400 Series |
Planned for VOSS 8.10.1 |
|
|
VSP 8600 Series |
Not Supported |
|
|
XA1400 Series |
VOSS 8.1.5 |
Note
Fabric Extend Tunnel IS-IS MTU configuration is added to the document in advance of Fabric Extend Integration with ExtremeCloud SD-WAN support. Feature support is planned for 8.10.1.
You can configure a unique IS-IS MTU value for each Fabric Extend (FE) tunnel. The IS-IS MTU gets applied to IS-IS packets that get sent through the interface.
You can configure each IS-IS logical interface with a unique MTU value for each FE tunnel to improve fragmentation and reassembly in WAN connectivity. This configuration can be applied to standard WAN connections such as MPLS IP WAN. For the XA1400 Series, this configuration can also be applied to internet-based connections through a NAT router. To configure the MTU, see Configure Fabric Extend. For more information about Fabric Extend options for SD-WAN, see SD-WAN.
Note
FE Tunnel IS-IS MTU is an optional configuration that applies to IS-IS packets only. The MTU for data packets is configured separately. For example, with SD-WAN deployments, the MTU for data packets is managed via the SD-WAN Appliance.
The FE Tunnel IS-IS MTU configuration is supported only for Fabric Extend tunnels that run over a Layer 3 core network (FE-IP). This configuration is not supported for Fabric Extend tunnels over a Layer 2 core network.
Fragmentation and reassembly of IS-IS packets is based on the IS-IS MTU value configured for the IS-IS logical interface that connects to the FE tunnel. For Layer 3 IS-IS logical interfaces, you can change the IS-IS MTU configuration at any time. The supported range, in bytes, is 750 to 1600 with a default of 1600.
For example, if you configure an FE tunnel with an IS-IS MTU of 900, and a packet size of 1950 is received on UNI with the destination on the FE tunnel, the system fragments the original 1950-sized packet into the three packets (900, 900, 150) with a packet size equal to or less than 900. The system transmits the three fragmented packets over the IS-IS logical interface of the FE tunnel. After the fragmented packets are received at the destination, the system reassembles the original 1950-sized packet.
Note that for reassembly to succeed, the fragments must arrive at the destination switch in the correct order (based on the offset). Otherwise, the fragments are discarded.
Note
For the XA1400 Series, the MTU range, in bytes, is 750 to 9000 with a default MTU of 1950. Also, unlike other models, the XA1400 Series supports the MTU configuration for both IS-IS packets and data packets natively.If route MTU is not configured, the MTU value for each FE tunnel is applicable to ingress and egress traffic on the tunnel.
Note
System MTU maximum is a separate configuration. You can configure a system maximum MTU size of 1522, 1950, or 9022. The default value is 1950.