Rstp support for pb and pbb – Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare Switching Configuration Guide
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RSTP support for PB and PBB
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RSTP support for PB and PBB
A PBB network is comprised of a set of Backbone Core Bridges (BCBs) and Backbone Edge Bridges
(BEBs). BEBs are interconnected by some or all of the S-VLANs supported by a PB network. Each
BEB provides interfaces that encapsulate customer frames, thus allowing customer MAC
addresses (C-MAC) and VLANs (S-VLAN) to be independent of backbone MAC addresses (B-MAC)
and VLANs (B-VLAN) used to relay those frames across the backbone.
In Brocade NetIron CES and Brocade NetIron CER, RSTP over PBB is supported in previous releases
implemented using the ESI framework.
As of NetIron R05.4.00, support for RSTP in PBB and PB domain is performed by running RSTP over
local VPLS VLAN on Brocade NetIron XMR and Brocade MLX series platforms.
Consider a scenario where all BEBs (AS - Access Switch) are connected to two BCBs (CS - Core
Switch) to provide dual home for all the BEBs, and all PBs (ES - Edge Switch) are connected to two
BEBs to provide dual home for all the PBs in the network. With the dual homing of the ASs to the
CSs and ESs to the ASs, all failures are protected. This dual homing support creates potential loops
in a PB network and PBB network. To achieve the functionality of dual homing of AS and ES, the
active topology of a PB network and PBB network area should be isolated by running different
instance of RSTP.
FIGURE 95
RSTP isolation in dual homing of AS and ES
The network shown in
has two Core Switches (CSs) to provide resiliency in the core. The
CS functions as a Backbone Core Bridge (BCB). All Access Switches (AS) in the network dual home
to the two CSs. The AS functions as a Backbone Edge Bridge (BEB). The CSs do not have any
service interfaces. The function of the CS is to switch traffic between the ASs. As a BCB, a CS will
switch on the outer PBB B-tag and will not perform any PBB encapsulation.
The AS and CS switches in the network will form a single RSTP region. With the dual homing of the
ASs to the CSs, all failures are protected against. ES dual homing will help to protect the failure of
AS.
CS
CS
AS
AS
AS
AS
ES
ES
ES
ES
ES
Core RSTP instance
Edge RSTP instance
under different VPLS
instance