Design Reference

3 Virtual Services Network [VSN]) across the MAC-in-MAC backbone. With
Layer 2 VSNs, you associate the I-SID with a customer VLAN, which is
then virtualized across the backbone. With Layer 3 VSNs, you associate
the I-SID with a customer VRF, which is also virtualized across the
backbone.
service level
agreement (SLA)
A service contract that specifies the forwarding service that traffic receives.
Shortest Path
Bridging (SPB)
Shortest Path Bridging is a control Link State Protocol that provides a loop-
free Ethernet topology. There are two versions of Shortest Path Bridge:
Shortest Path Bridging VLAN and Shortest Path Bridging MAC. Shortest
Path Bridging VLAN uses the Q-in-Q frame format and encapsulates the
source bridge ID into the VLAN header. Shortest Path Bridging MAC uses
the 802.1 ah MAC-in-MAC frame format and encapsulates the source
bridge identifier into the B-MAC header.
Shortest Path
Bridging MAC
(SPBM)
Shortest Path Bridging MAC (SPBM) uses the Intermediate-System-to-
Intermediate-System (IS-IS) link-state routing protocol to provide a loop-
free Ethernet topology that creates a shortest-path topology from every
node to every other node in the network based on node MAC addresses.
SPBM uses the 802.1ah MAC-in-MAC frame format and encapsulates the
source bridge identifier into the B-MAC header. SPBM eliminates the need
for multiple overlay protocols in the core of the network by reducing the
core to a single Ethernet-based link-state protocol, which can provide
virtualization services, both layer 2 and layer 3, using a pure Ethernet
technology base.
shortest path tree
(SPT)
Creates a direct route between the receiver and the source for group
members in a Protocol Independent Multicast-Sparse Mode (PIM-SM)
domain.
Simple Loop
Prevention Protocol
(SLPP)
Simple Hello Protocol that prevents loops in a Layer 2 network (VLAN).
single-mode fiber
(SMF)
One of the various light waves transmitted in an optical fiber. Each optical
signal generates many modes, but in single-mode fiber only one mode is
transmitted. Transmission occurs through a small diameter core
(approximately 10 micrometers), with a cladding that is 10 times the core
diameter. These fibers have a potential bandwidth of 50 to 100 gigahertz
(GHz) per kilometer.
small form-factor
pluggable (SFP)
A hot-swappable input and output enhancement component used with
Avaya products to allow gigabit Ethernet ports to link with other gigabit
Ethernet ports over various media types.
Glossary
156 Network Design Reference for Avaya VSP 4000 Series December 2014
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