Multicast Flow Distribution Over Mlt - Avaya 8600 Configuration Manual

Link aggregation fundamentals
MultiLink trunking and auto-negotiation interaction
In this release, MLT requires that all ports operate at the same speed. When you use MLT with
LACP, LACP dynamically checks for proper speed on all port members. You are no longer
required to have similar physical connection types. For example, you can mix a fiber port with
a copper port. When you use auto-negotiation with MLT and not LACP, you need to ensure
that all ports run at the same speed.

Multicast flow distribution over MLT

MLT provides a mechanism to distribute multicast streams over a MultiLink trunk. This
mechanism is based on source-subnet and group addresses. You can use it to choose the
address and bytes in the address for the distribution algorithm.
The multicast flow distribution over MLT algorithm is the same multicast flow distribution
algorithm used in IEEE 802.3ad-based link aggregation. As a result, you can distribute the load
on the MLT ports and achieve even stream distribution. In applications such as Television (TV)
distribution, multicast traffic distribution is important because bandwidth requirements are
substantial when a large number of TV streams are employed.
When you configure flow distribution over MLT, Avaya recommends that you choose source
and group masks that result in even traffic distribution over the MultiLink trunk links. For
example, if the group addresses change incrementally while few sources sending to different
groups, use a source mask of 0.0.0.0 and a group mask of 255.255.255.255. In most cases,
this provides a sequential distribution of traffic on the MultiLink trunk links.
When changing the state parameters of multicast flow distribution, minor traffic interruptions
can occur.
For a detailed description of commands used to configure multicast flow distribution over MLT,
see Avaya Ethernet Routing Switch 8800/8600 Configuration — IP Multicast Routing
Protocols, NN46205-501.
Multicast distribution algorithm
To determine the port for a particular source, group (S, G) pair, use the number of active MLT
ports to MOD. The number generated by the XOR (exclusive OR operation) for each byte of
the masked group address, with the masked source address.
By default, the group mask and source mask is 255.255.255.255. A byte with a value of 255
in the mask indicates that the corresponding byte in the group or source address is taken into
account when the algorithm is applied.
The following is an example:
group address G[0].G[1].G[2].G[3]
group mask GM[0].GM[1].GM[2].GM[3]
14 Configuration — Link Aggregation, MLT, and SMLT
Comments? infodev@avaya.com
January 2012