Spbm Campus Architecture - Avaya 8800 Planning And Engineering, Network Design

SPBM design guidelines

SPBM campus architecture

For migration purposes, you can add SPBM to an existing network that has SMLT configured. In
fact, if there are other protocols already running in the network such as OSPF, you can leave them
in place too. SPBM uses IS-IS, and operates independently from other protocols. However, Avaya
recommends that you eventually eliminate SMLT in the core and other unnecessary protocols. This
reduces the complexity of the network and makes it much simpler to maintain and troubleshoot.
Whether you configure SMLT in the core or not, the main point to remember is that SPBM separates
services from the infrastructure. For example, in a large campus, a user may need access to other
sites or data centers. SPBM enables you to grant that access by associating the user to a specific I-
SID. This mechanism enables the user to do his work without getting access to another
department's confidential information.
The following figure depicts a topology where the BEBs in the Edge and Data Center Distribution
nodes (blue icons) are configured in SMLT Clusters. Prior to implementing SPBM, the core nodes
(yellow icons) would also have been configured as SMLT Clusters. When migrating SPBM onto this
network design, it is important to note that you can deploy SPBM over the existing SMLT topology
without any network interruption. Once the SPBM infrastructure is in place, you can create VSN
services over SPBM (or migrate them from the previous end to end SMLT-based design).
After migrating all services to SPBM, the customer VLANs (C-VLANs) will exist only on the BEB
SMLT Clusters at the edge of the SPBM network (blue icons). The C-VLANs will be assigned to an
I-SID instance and then associated with either a VLAN in an L2 VSN or terminated into a VRF in an
L3 VSN. You can also terminate the C-VLAN into the default Global Routing Table (GRT), which
uses IP Shortcuts to route over the SPBM core.
In an SPBM network design, the only nodes where it makes sense to have an SMLT Cluster
configuration is on the BEB nodes where VSN services terminate. These are the SPBM nodes
where C-VLANs exist and these C-VLANs need to be redundantly extended to non-SPBM devices
such as L2 edge stackable switches. On the BCB core nodes where no VSNs are terminated and no
L2 edge stackables are connected, there is no longer any use for the SMLT Clustering functionality.
Therefore, in the depicted SPBM design, the SMLT/IST configuration can be removed from the core
nodes because they now act as pure BCBs that have no knowledge of the VSN they transport and
the only control plane protocol they need to run is IS-IS.
Since SMLT BEB nodes exist in this design (the edge BEBs) and it is desirable to use equal cost
paths to load balance VSN traffic across the SPBM core, all SPBM nodes in the network are
configured with the same two B-VIDs.
June 2016 Planning and Engineering — Network Design
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