Network Virtualization using Extreme Fabric Connect

Network Virtualization Using Extreme Fabric Connect
© 2019 Extreme Networks, Inc. All rights reserved. 145
Figure 85 Multi-Link Trunking (MLT) Used in Core and Access
In the Extreme Networks VSP and ERS series terminology, this is referred to as Multi-Link Trunking (MLT)
when the link aggregation is statically configured and as Link Aggregation Groups (LAG) when the
aggregation is done dynamically by the LACP protocol. In the case of a static MLT, we also refer to
Distributed-MLT (DMLT) when the MLT is configured either on a stacked switch comprising multiple units
or a chassis, and where the DMLT Ethernet links are distributed across the different slots of the chassis. This
provides additional protection against a unit failure in a stack or a line card failure in the case of a chassis.
In the ExtremeXOS platforms, the ability to perform link aggregation is referred to as load sharing.
Tip
LACP is generally recommended on access links, i.e. when doing link aggregation towards
servers and/or non-Extreme Networks networking devices (e.g., firewalls), as this
combines both the link aggregation and link integrity capabilities of the LACP protocol.
Tip
When doing link aggregation between Extreme Networks VSP and ERS series devices on
core links, it is recommended to use static MLTs with VLACP configured on each of the
underlying physical Ethernet ports. This provides a simpler configuration (than LACP),
greater control of which core links are to be aggregated together, as well as benefitting of
much faster VLACP timers for detecting any link faults, as described in the preceding
section.
Tip
When doing link aggregation between Extreme Networks VSP FA Servers and
ExtremeXOS FA Proxy access switches, it is recommended to use LACP SMLT / load
sharing. This provides the similar benefits to a static MLT config with VLACP.
Tip
In the Extreme Networks Fabric Connect SPB implementation, an MLT can be used as a
logical NNI, where IS-IS is configured on the MLT bundle and only sees the logical
aggregate in shortest path computations.
Tip
Most Extreme Networks VSP, ERS, and ExtremeXOS series switching platforms support
the ability to aggregate up to eith Ethernet ports into either an MLT or LAG, with the
exception of the lower end, lower cost access switches which will only support four.
Every device doing link aggregation is responsible for implementing a hashing algorithm to distribute
egress traffic across all available links forming the MLT/LAG.