Configuration Guide

Table Of Contents
©2021 Extreme Networks, Inc. All rights reserved
October 2021
18
Standard Year Name Loop free
Topology
by:
Service
IDs
Provisioning
Virtualization
of
IEEE
802.1Q
1998
Virtual
LANs
(VLAN
Tagging)
Spanning
Tree
SMLT
4096 Edge and
Core
Layer 2
IEEE
802.1ad
2005
Provider
Bridging
(QinQ)
Spanning
Tree
SMLT
4096x4096 Edge and
Core
Layer 2
IEEE
802.1ah
2008 Provider
Backbone
Bridging
(MacInMac)
Spanning
Tree
SMLT
16 Million Edge and
Core
Layer 2
IEEE
802.1aq
2012 Shortest
Path
Bridging
(SPBM)
Link-
State-
Protocol
(IS-IS)
16 Million Only Service
Access
Points
IEEE: Layer 2
IETF draft:
Layer 3
Unicast &
Multicast
Table 1: IEEE Standards culminating with SPBM
SPBM is based on the 802.1ah encapsulation schema but does not depend on spanning tree to provide a
loop free Layer 2 domain, instead it uses the nodal based IS-IS topology protocol. The IEEE is reworking
the spanning tree specification 802.1D to include the new SPB solution. The intention is that once the
standard is implemented in network products, the network operator will be able to choose a shortest path
bridging topology protocol or the legacy root tree based option.
In addition to the Layer 2 virtualization support that SPBM provides, the model is being extended to also
support Layer 3 virtualization via the IETF Draft IP/SPB-Unbehagen. Where L2 virtualization associates an
ISID to an edge VLAN in such a way as to extend that VLAN across the backbone, with the L3 extension a
VRF can also be associated to an ISID in such a way as to extend a virtualized L3 routing instance across
the backbone.
Extreme also enhanced the SPBM capability by adding multicast support which greatly simplify the
multicast deployment and provide resiliency to multicast at the same time.
In summary, SPBM brings to the Enterprise network the features, functionalities and scalability demanded
by carriers via the use of a single simple and dynamic link state routing protocol which is IS-IS.