Dell Force10 C150 Manual page 55

Deploying the Dell Force10 MXL into a Cisco Nexus Network Environment
LAG
Link Aggregation Group (LAG) is a configured bundle of Ethernet links that are treated as the same
logical Ethernet link. There are multiple terms that apply to LAGs including channel group, port
channel, trunk, and even some server Ethernet interface teaming involves a collection of links that
would be considered a LAG. However while channel group and port channel always apply to LAG use,
trunk and teaming do not.
LAN
A Local Area Network (LAN) is a term for a network that services a limited area from the size of a
single table to a large as an office building. They are generally interconnected using Ethernet switches.
The term is sometimes applied to a network involving a single broadcast domain and sometimes applied
to a network involving multiple broadcast domains separated into VLANs (and often rejoined via
routing).
Link
Link is a term in networking that refers to a connection made between two nodes in a network. In
Ethernet networking it is generally used to refer to a direct connection between two ports.
MAC Address
Media Access Control Address (MAC Address) is a layer-2 node identifier. In Ethernet bridging, MAC
addresses are used for source and destination identification. They can also be used as system
identifiers since vendor-assigned (or burned-in) MAC addresses are globally unique. An Ethernet MAC
address is 48 bits long and generally written in groupings of two hexadecimal digits often separated by
colons or hyphens like this: 00:1e:c9:00:cb:01. But, are sometimes written in groupings of four
hexadecimal digits separated by periods like this: 001e.c900.cb01
MLAG
Multi-chassis Link Aggregation Group (MLAG) is a LAG implementation that connects across multiple
switches on one side of the logical aggregated link. This requires shared management of the logical link
between the switches sharing a side and situational forwarding of frames that differs from the
forwarding that would be present across the multiple LAGs that an MLAG replaces. There is no standard
method for implementing an MLAG but multiple vendor specific methods. Nexus vPC and Force10 VLT
are examples of MLAG implementations.
MSTP
Multiple Spanning-Tree Protocol (MSTP) is a standards-based modified version of the rapid spanning
tree protocol that carries multiple spanning tree instances within its rapid spanning-tree protocol
packet. Spanning-tree instance 0 is assigned to the common rapid spanning-tree instance and
additional instances above 0 may be configured. For each spanning-tree instance, a root switch is
elected and unique active and backup links can be chosen providing potentially unique traffic paths on
the network per instance. Each VLAN can then be assigned to a spanning-tree instance allowing active
traffic on separate VLANs to potentially utilize separate paths across the network. In order for
interconnected switches to participate together in more than the common spanning-tree instance, they
must have the same MSTP configuration (a checksum of this configuration is included the spanning-tree
protocol packet and must be the same between switches in order for them to participate). MSTP is
originally defined in the IEEE 802.1s standard and is included in 802.1q IEEE Virtual LANs standard.
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