Configuration Guide

Table Of Contents
©2021 Extreme Networks, Inc. All rights reserved
October 2021
23
Source address learning is disabled
Unknown mac discard is disabled
Essentially the VLAN becomes a header indicating the SPBM network to use.
Modification of the VLAN behavior is necessary to ensure proper control over the SPBM traffic.
Although it is recommended to use BVIDs that are in the upper range, using a BVID less than
4000 may have to be used if tunneling SPB across an MPLS or IP network via a router GRE
tunnel. For example, the Ayava Secure Router supports VLAN tunneling via GRE with a
restriction of allowin
g
onl
y
VLAN ID’s of less than 4000.
2.5
B-MAC (System ID)
Whereas OSPF computes the shortest path to destination subnets and then populates the IP routing table
with the results, IS-IS (as used with SPB) computes the shortest path to backbone node MAC addresses
(B-MACs) and then populates the backbone MAC tables. The B-MAC addresses are advertised in IS-IS via
one or more backbone VLAN IDs (B-VIDs). In summary, frames are forwarded using the System-Id as the
Backbone Source Access (B-SA) to a specific node using the Backbone Destination Address (B-DA). Note
that the backbone nodes will know how to reach all the B-MACs (IS-IS will have programmed the B-VID
MAC tables according) while the Customer MACs (C-MACs) will only be learned on the appropriate BEB
nodes which terminate the virtual services.
The SPB forwarding database (FDB) will contain a combination of unicast and multicast MAC addresses.
SPB uses source specific multicast trees. There has to be a unique multicast tree for every BEB across all
B-VIDs provisioned and for every Service Instance (ISID) which requires delivery of multicast/broadcast
(L2VSNs and only L3VSNs if enabled for IP Multicast). In terms of IS-IS computation there will be as many
multicast SPT trees as there are SPB nodes across each B-VID. These trees will then be further pruned
into Service (ISID) specific multicast SPTs based on which BEBs are configured with the corresponding
ISID. In the data plane every individual Service Specific multicast SPT will have a unique Multicast MAC
address defined which is obtained by combining the ingress BEB Nick-name (referred to as the SP
SourceID; 20 bits) with the ISID service identifier (24 bits).
SPB Unicast FDB
CLI
ERS-8800:5# show isis spbm unicast-fib
ERS-8800:5# show isis spbm unicast-fib vlan <vlan-id>
ACLI
ERS-8800:5#show isis spbm unicast-fib
ERS-8800:5#show isis spbm unicast-fib vlan <vlan-id>
================================================================================
SPBM UNICAST FIB ENTRY INFO
================================================================================
DESTINATION BVLAN SYSID HOST-NAME OUTGOING COST
ADDRESS INTERFACE