Ad-Based Link Aggregation - Avaya 8800 Planning And Engineering, Network Design

Redundant network design
To avoid this problem, protect your single-point-of-failure links with an MLT backup path. Configure
your spanning tree networks so that blocked ports do not divide your VLANs into two noncontiguous
parts. Set up your VLANs so that device failures do not lead to the split subnet VLAN problem.
Analyze your network designs for such failure modes.

802.3ad-based link aggregation

Link aggregation provides link layer redundancy. Use IEEE 802.3ad-based link aggregation (IEEE
802.3 2002 clause 43) to aggregate one or more links together to form Link Aggregation Groups
(LAG) to allow a MAC client to treat the LAG as if it were a single link. Using link aggregation
increases aggregate throughput of the interconnection between devices and provides link
redundancy. LACP can dynamically add or remove LAG ports, depending on their availability and
states.
Although IEEE 802.3ad-based link aggregation and MLT provide similar services, MLT is statically
defined. By contrast, IEEE 802.3ad-based link aggregation is dynamic and provides additional
functionality.
802.3ad-based link aggregation navigation
• LACP and MLT
• LACP and SMLT: Interoperability with servers (and potentially third-party switches)
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• LACP and spanning tree interaction
• LACP and Minimum Link
• Link aggregation group rules
LACP and MLT
When you configure standards-based link aggregation, you must enable the aggregatable
parameter. After you enable the aggregatable parameter, the LACP aggregator is one-to-one
mapped to the specified MLT.
A newly-created MLT/LAG adopts the VLAN membership of its member ports when the first port is
attached to the aggregator associated with this LAG. When a port is detached from an aggregator,
the port is deleted from the associated LAG port member list. When the last port member is deleted
from the LAG, the LAG is deleted from all VLANs and STGs.
After the MLT is configured as aggregatable, you cannot add or delete ports or VLANs manually.
To enable tagging on ports belonging to a LAG, first disable LACP on the port, enable tagging on
the port, and then enable LACP.
LACP and SMLT: Interoperability with servers (and potentially third-party
switches)
To better serve interoperability with servers (and potentially certain third-party switches) in SMLT
designs, the Avaya Ethernet Routing Switch 8800/8600 provides a system ID configuration option
for Split MultiLink Trunk (SMLT).
June 2016
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Planning and Engineering — Network Design
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